Sarcoidosis from head to toe: What the radiologist needs to know

Sarcoidosis from
Head to Toe:
What the Radiologist
Needs to Know
DR ABHINEET DEY
PGT 1, DEPARTMENT OF RADIOLOGY
SILCHAR MEDICAL COLLEGE & HOSPITAL

RadioGraphics: Vol. 38, No. 4
Dhakshinamoorthy Ganeshan, Christine O. Menias, Meghan G. Lubner, Perry J. Pickhardt,
Kumaresan Sandrasegaran, and Sanjeev Bhalla RadioGraphics 2018 38:4, 1180-1200

Sarcoidosis
SARCOIDOSIS IS AN IDIOPATHIC SYSTEMIC
GRANULOMATOUS DISORDER CHARACTERIZED BY THE
DEVELOPMENT OF NONCASEATING GRANULOMAS IN
VARIOUS ORGANS.

Risk factors
Environmental factors:
◦ Insecticides, mold, inorganic particles, and agricultural chemicals increase
the risk of sarcoidosis
◦ Individuals involved in firefighting, metal processing, and the U.S. Navy
service have been shown to have a higher risk for developing this disease
Microbiological factors: Following organisms pose a slightly increased
risk for sarcoidosis
◦ Propionibacterium
◦ Mycobacteria

Diagnosis
Patients suspected of having sarcoidosis should undergo comprehensive
evaluation that includes obtaining a thorough clinical history and
performing a physical examination and chest radiography.
Clinical presentation:
◦ Nonspecific respiratory symptoms (9–19% cases): Cough, dyspnea, and
chest pain
◦ Erythema nodosum
◦ Acute ankle arthritis
◦ Generalized fatigue: Common albeit nonspecific symptom
Disease biomarkers: Serum interleukin-2 receptor, neopterin,
angiotensin-converting enzyme, chitotriosidase, lysozyme, plasma N-
terminal probrain natriuretic peptide, and troponin T levels

Histopathological features
Noncaseating granulomas: Characteristic histologic feature of
sarcoidosis. It can contain the following structures:
◦ Central region: Epithelioid cells, macrophages, multinucleated giant cells,
and CD4+ T cells
◦ Peripheral region: CD8+ T cells, B lymphocytes, and fibroblasts
Other features (may be present): Asteroid bodies, Schaumann bodies,
calcium oxalate crystals, and Hamazaki-Wesenberg bodies
The presence of necrosis should lead to a search for an alternative
diagnosis because this finding is rare in sarcoidosis, with the exception
of a controversial rare sarcoid variant called necrotizing sarcoid
granulomatosis

Node biopsy–
confirmed
sarcoidosis in a 51-
year-old woman
with thoracic
nodes and hepatic
involvement.
Photomicrograph
(hematoxylin-eosin stain;
original magnification, 334)
shows a central giant cell
(black arrow) within a
central collection of
epithelioid cells, surrounded
by a rim of lymphocytes
(white arrows) in the
periphery. Collagen bands
(arrowheads) also are seen.

Pulmonary
sarcoidosis
PULMONARY SARCOIDOSIS IS THE MOST COMMON
PRESENTATION BY FAR, SEEN IN > 90% CASES

Chest radiography
Presence of characteristic chest radiographic abnormalities in the correct
clinical context may be sufficient for diagnosis of sarcoidosis
Characteristic imaging finding: Symmetric hilar lymphadenopathy
(although other conditions such as lymphoma, tuberculosis, and
metastases present with mediastinal widening, sarcoidosis presents in a
characteristically symmetrical fashion)
Other pulmonary parenchymal abnormalities:
◦ Micronodules (often with a perilymphatic distribution)
◦ Macronodules (often with a peribronchovascular distribution)
◦ Reticulonodular opacities
◦ Ground-glass changes
◦ Pulmonary fibrosis

Pulmonary sarcoidosis in a 32-year-old woman
Posteroanterior chest radiograph (a) and axial chest CT image (mediastinal window) (b) show
bilateral hilar (white arrows) and mediastinal (black arrow) adenopathy.

Scadding radiographic staging
Stage Description Incidence
Stage 0 Normal finding 5-15%
Stage I Thoracic adenopathy 25-65%
Stage II Thoracic adenopathy + pulmonary infltrates 25-65%
Stage III Pulmonary infltrates only 10-15%
Stage IV Pulmonary fibrosis 5%
Scadding JG. Prognosis of intrathoracic sarcoidosis in England: a review of 136 cases after five years’
observation. BMJ 1961;2(5261):1165–1172.

CT imaging
Chest radiography is the most common imaging modality used for
pulmonary sarcoidosis, but CT is used frequently for a more
comprehensive evaluation.
Imaging for extrapulmonary sarcoidosis depends on the site of
suspected involvement and often requires CT and magnetic resonance
(MR) imaging.
CT, which is more sensitive for detection of parenchymal abnormalities
and thoracic lymphadenopathy. CT also may be useful in patients for
whom there is a high clinical suspicion for complications such as
aspergilloma, concurrent infection, or malignancy.
CT can be helpful for guiding transbronchial biopsy and endobronchial
ultrasonographically (US)-guided fine-needle aspiration

CT imaging
CHARACTERISTIC CT FINDINGS
◦ Well-defined micronodules
measuring 2–5 mm with a
perilymphatic distribution along
the bronchovascular bundles,
interlobular septa, interlobar
fissures, and subpleural regions
◦ Nodules tend to occur more
commonly in the middle to upper
lung zones
◦ Air trapping at expiratory CT is also
seen frequently
ATYPICAL CT FINDINGS
Mass-like opacities
Confluent alveolar opacities
(alveolar sarcoid)
Bulky confluent pulmonary
masses
Ground-glass opacities
Interlobular septal thickening
Fibrocystic changes
Miliary opacities

Pulmonary sarcoidosis in a 24-year-old man
Axial thin-section chest CT images show pulmonary micronodules in a perilymphatic
distribution, including perifissural nodules (black arrow) and peribronchovascular nodules
(white arrow).

Complication: Pulmonary fibrosis
Pulmonary fibrosis may develop in 20%–25% of patients with
sarcoidosis.
CT imaging patterns: Typically fibrotic changes are seen along the upper
and middle zones of the lungs
◦ Predominant central bronchial distortion, associated with obstruction and
air trapping (47% cases)
◦ Peripheral honeycombing, associated with restriction and lower diffusion
capacity of the lung for carbon monoxide (29% cases)
◦ Diffuse linear pattern, with minimal functional impairment (24% cases)

Pulmonary sarcoidosis in a 48-year-old man
Posteroanterior chest radiograph (a) and axial chest CT image (b) show central bronchial
distortion (arrows), reticulonodular opacities, and volume loss consistent with pulmonary
fibrosis.

Complications: Pulmonary
arterial hypertension
CT is more sensitive for diagnosis of pulmonary arterial hypertension
than is radiography.
CT imaging:
◦ Dilated pulmonary trunk > 29 mm in diameter
◦ Enlarged right and left pulmonary arteries
◦ Ratio of main pulmonary artery to the ascending aorta > 1. This ratio may
be predictive of mortality, independent of all other CT patterns

Complications: Infection
Pulmonary aspergillosis and mycetoma may develop in up to 2% of
sarcoidosis patients
Incidence may be higher in those with pre-existing lung conditions such
as:
◦ Pulmonary fibrosis
◦ Cystic lung disease
◦ Pre-existing pulmonary cavities
◦ Bronchiectasis

FDG-PET & PET/CT
Fluorine 18 (18F) fluorodeoxyglucose (FDG) positron emission
tomography (PET) and PET/CT have been shown to be increasingly
useful in the management of sarcoidosis in diagnosis, staging,
evaluation of disease activity and assessment of treatment response
◦ Detecting sites of extra-thoracic involvement, especially those that are occult
on anatomic images
◦ Identify disease activity and severity in sarcoidosis
◦ Evaluating treatment response in patients with pulmonary and
extrapulmonary sarcoidosis

Cardiac
sarcoidosis
AUTOPSY STUDIES REPORT CARDIAC INVOLVEMENT IN
25% OF SARCOIDOSIS CASES, BUT CLINICALLY EVIDENT
DISEASE IS SEEN IN ONLY 5% OF CASES

Clinical presentation
Cardiac sarcoidosis can result in various cardiac abnormalities including:
◦ Atrioventricular block
◦ Bundle branch block
◦ Ventricular tachycardia
◦ Heart failure
◦ Sudden death

Imaging
Cardiac MR: Patchy and multifocal late gadolinium enhancement in the
basal segments, particularly of the septum and the lateral wall, and
tends to affect the mid-myocardium and epicardium, sparing the sub-
endocardium
Resting myocardial perfusion sequence with 18F FDG PET: 18F FDG PET
also has an increasingly important role in the diagnosis, management,
and prognostication of cardiac sarcoidosis
◦ Active inflammatory sarcoidosis: Patchy focal 18F FDG uptake with or
without a perfusion defect
◦ Presence of a perfusion defect without FDG uptake is in keeping with cardiac
sarcoidosis associated with myocardial fibrosis and scarring

Cardiac sarcoidosis in a 45-year-old man
The patient presented with progressively worsening dyspnea on exertion, a new right bundle branch
block on an electrocardiogram (not shown), and a 2:1 atrioventricular block during exercise. (a)
Sagittal cardiac MR image shows patchy areas of delayed gadolinium enhancement (arrows).
Localized asymmetric basal septal thinning and right ventricular hypertrophy were also seen.
(b) Sagittal fused PET/MR image shows heterogeneous FDG uptake (arrows) in the
corresponding areas of abnormality.

Definitive diagnosis
Electrocardiogram (non-specific abnormalities):
◦ Atrioventricular block
◦ Bundle branch block
Echocardiography (non-specific findings):
◦ Left ventricular regional wall motion abnormalities
◦ Thinning of the basal interventricular septum
◦ Thinning of the left ventricular free wall
◦ Dilatation of the left ventricle
◦ Reduced ejection fraction
◦ Ventricular aneurysms
The criterion standard for diagnosis of cardiac sarcoidosis is histologic
confirmation of noncaseating granulomas by means of endomyocardial
biopsy.
However, this is an invasive procedure and may be associated with a low
diagnostic yield of 20%–50% owing to sampling errors

Differential diagnosis
Myocardial infarction: Late gadolinium enhancement typically is limited
to the subendocardial or transmural region and characteristically is
restricted to the affected vascular territory
Myocarditis: Delayed enhancement in a nonvascular distribution and
often is associated with wall abnormalities. Subepicardial enhancement
is the dominant pattern in most cases of myocarditis, although
transmural enhancement may develop in cases of severe myocardial
damage.The degree of enhancement is reported to become less intense
over weeks, especially with scar development.
Cardiac amyloidosis: Biventricular hypertrophy and diffuse or
heterogeneous left ventricular wall enhancement.
Correlating the clinical findings with imaging features may be useful in
narrowing the differential diagnosis.

Neurosarcoidosis
AUTOPSY STUDIES REPORT A HIGH INCIDENCE OF
SUBCLINICAL ASYMPTOMATIC NEUROSARCOIDOSIS
OF 25–50%.

Neurosarcoidosis
Clinically recognized symptomatic central nervous system sarcoidosis is
present in 5–15% of all patients with sarcoidosis have extraneural
manifestations.
Isolated CNS sarcoidosis is rare, affecting 1% of all patients with
sarcoidosis.
Clinical presentation depends on site of involvement and can include
facial nerve palsy, vision loss, diplopia, headache, seizure, meningism,
weakness, and paresthesia.

Cranial neuropathy
Facial nerve involvement: Common manifestation in patients with
clinically symptomatic neurosarcoidosis
◦ Bilateral facial nerve palsy (up to one-third cases)
◦ Heerfordt syndrome: Facial nerve palsy, fever, parotid gland enlargement,
and uveitis
Other cranial nerves involved: Olfactory, auditory, and optic nerves
MR imaging: Abnormal enlargement and enhancement of the involved
cranial nerves

Neurosarcoidosis in a 67-year-old woman
Axial contrast-enhanced T1-weighted MR image shows nodular enhancement in the left optic
nerve (arrow), sella turcica, and leptomeningeal region

Leptomeningeal involvement
Leptomeningeal involvement in sarcoidosis (sarcoid meningitis) is reported
to develop in up to one-third of patients with neurosarcoidosis
Clinical presentation: Hydrocephalus, seizures, or cognitive decline
MR imaging:
◦ Diffuse or nodular thickening and enhancement of the leptomeninges on
contrast-enhanced T1-weighted MR images
◦ Spread of disease following disruption of blood brain barrier: Multiple small
granulomas may coalesce, resulting in intra-axial masses with surrounding
edema
◦ CSF abnormalities: Diffuse leptomeningeal gadolinium enhancement
◦ Dural involvement: T2 hypointense focal dural masses
However, these findings are not specific and may be seen in other
conditions such as tuberculosis, lymphoma and metastases. Correlation
with abnormalities of the cerebrospinal fluid may be helpful.

Neurosarcoidosis in a 53-year-old woman
(a) Coronal contrast material–enhanced T1-weighted MR image shows thick nodular pachymeningeal
enhancement (arrows) along the basilar dura, including near the cerebellopontine angles and tentorial
reflections bilaterally. (b) Axial contrast-enhanced T1-weighted MR image shows nodular enhancement along
the seventh and eighth cranial nerve complex (arrow). (c) Axial T2-weighted fluid-attenuated
inversionrecovery MR image shows a hyperintense lesion in the left medulla (arrow), a finding consistent with
intraparenchymal involvement.

Brain parenchymal
involvement
Sarcoid granulomas may involve any portion of the brain parenchyma
but are found more often in the hypothalamus and pituitary gland,
which can result in diabetes insipidus.
Imaging findings:
◦ Plaque-like or nodular thickening in the infundibular stalk and optic chiasm.
(T1 isointense or T2 hypointense lesions with marked enhancement on MR
imaging)
◦ Hydrocephalus (5–12% cases)
◦ Sarcoidosis involving cerebral white matter, cerebellum, and brainstem:
Multiple tiny T2-hyperintense and T1-hypointense periventricular white
matter lesions
Active sarcoidosis lesions commonly show enhancement with
intravenous gadolinium administration. After therapy, these lesions may
show diminished T2 hyperintensity and decreased enhancement.

MR classification of
neurosarcoidosis
Dumas et al classified central nervous system sarcoidosis into three types.
Type 1 (reversible): Parenchymal lesions that show enhancement on
gadolinium-enhanced T1-weighted images
Type 2 (irreversible): Non-enhancing nodular or confluent abnormalities
with T2 high signal intensity in the periventricular regions and in the deep
white matter, which mimic demyelinating lesions seen in multiple sclerosis)
Type 3 (irreversible): 2-8 mm multifocal patchy T2-hyperintense lesions in
the subcortical white matter, which mimic those seen in small-vessel
atherosclerotic disease
Gadolinium enhancement may be a marker for biologically active lesions
and that enhancing lesions potentially are reversible and may regress after
corticosteroid therapy. In comparison, type 2 and type 3 lesions are
irreversible

Pituitary sarcoidosis in a 32-year-old woman
Sagittal contrast-enhanced T1-weighted MR image shows an avidly and heterogeneously
enhancing nodular mass in the sella turcica, extending to the optic chiasm (arrow).

Spinal cord involvement
Spinal cord involvement tends to manifest in elderly patients, with
lesions more commonly seen in the cervicothoracic spine.
Clinical features: Mimics those seen in cervical spondylitis
MR imaging: Typically T1 hypointense and T2 hyperintense lesions
with patchy enhancement
◦ Leptomeningeal enhancement
◦ Fusiform spinal cord enlargement
◦ Focal/diffuse intramedullary disease
◦ Intradural extramedullary lesions and extradural lesions
◦ Spinal cord atrophy
Cerebrovascular involvement: Also reported and may result in transient
ischemic attacks, strokes, and rarely, intracranial hemorrhage

Definitive diagnosis
The definitive diagnosis of neurosarcoidosis requires biopsy
confirmation. However, in most instances, this is not feasible, and a
diagnosis of probable neurosarcoidosis can be made on the basis of the
clinical evidence such as:
◦ Cerebrospinal fluid abnormalities: Elevated cerebrospinal fluid cell counts,
elevated protein levels, and the presence of oligoclonal bands
◦ MR imaging features of neurosarcoidosis
◦ Confirmation of systemic sarcoidosis:
◦ Biopsy of a nonneurologic site
◦ Positive results on a Kveim test
◦ Elevated serum angiotensin-converting enzyme
◦ Imaging findings of sarcoidosis at chest imaging or gallium imaging

Head & Neck
Sarcoidosis
10-15% CASES HAVE HEAD & NECK MANIFESTATIONS.
COMMON INVOLVED SITESINCLUDE THE ORBITS,
SINONASAL REGIONS, PHARYNX, HYPOPHARYNX, SALIVARY
GLANDS, THYROID GLAND, CERVICAL NODES, AND LARYNX

Orbital sarcoidosis
Ocular manifestations: Diagnosed clinically
◦ Anterior uveitis: Most common ocular manifestation (65%–71%)
◦ Posterior & intermediate uveitis
Optic nerve involvement: MR imaging
◦ T2-weighted images: Abnormal high signal intensity
◦ Contrast-enhanced T1-weighted images: Nodular thickening and enhancement
Lacrimal gland (CT & MR imaging): Abnormally enlarged and enhancing
lacrimal glands
Extraocular muscles (CT & MR imaging): Abnormal thickening and
enhancement in extraocular muscles and tendons.
Retrobulbar fat (CT & MR imaging): Heterogeneous, infiltrative, enhancing
soft tissue masses

Head and neck sarcoidosis in a 32-year-old
woman
Coronal contrast-enhanced T1-weighted MR image shows nodular thickening and enhancement of
the left lacrimal gland (white arrow) and superior, medial, and inferior recti muscles (black arrows).
Nodular thickening and enhancement also are seen in the right lateral rectus muscle and the right
maxillary sinus. The differential diagnosis includes consideration of pseudotumor, sarcoidosis, and
granulomatosis with polyangiitis. A diagnosis of noncaseating granuloma was confirmed on the basis
of biopsy results.

Parotid gland sarcoidosis
Parotid gland involvement may occur in 5% of patients with sarcoidosis.
Clinical manifestations: Enlargement of parotid gland, xerostomia, and
facial nerve palsy. Parotid gland involvement also may occur as part of
Heerfordt syndrome.
Gallium 67(67Ga)-citrate scintigraphy: Abnormal bilateral uptake in the
parotid and lacrimal glands, along with normal uptake in the
nasopharyngeal mucosa, commonly referred to as “the panda sign”.
However this sign is not pathognomic and may be seen in lymphoma
and Sjogren syndrome.

Head and neck sarcoidosis in a 37-year-old
man
Axial contrast-enhanced T1-weighted MR image shows a focal enhancing mass in the left
parotid gland. The presence of a noncaseating granuloma was confirmed on the basis of
biopsy results and was consistent with a diagnosis of sarcoidosis.

Sinonasal sarcoidosis
Clinical presentation: Nonspecific symptoms such as nasal obstruction
and rhinosinusitis
CT & MR imaging: Nodular thickening and enhancement in the nasal
septum and turbinates. Paranasal sinus involvement may result in soft-
tissue opacification.
More aggressive lesions may be associated with destruction of the
adjacent bones and may extend to intracranial structures. Sarcoidosis
also can involve the external ear, middle ear, and temporal bone

Laryngeal sarcoidosis
Laryngeal structures including the epiglottis, arytenoids, aryepiglottic
folds, and false vocal folds may be affected.
◦ Mild cases: Usually clinically silent but can result in hoarseness and dyspnea
◦ Severe cases: Stridor, mandating urgent tracheostomy
Imaging findings: Nonspecific but affected regions may show edema
and nodular thickening

Thyroid sarcoidosis
Sarcoidosis of the thyroid gland has been reported in up to 4% of
patients with sarcoidosis in autopsy studies
Ultrasonography (US): Diffuse enlargement and nonspecific thyroid
nodules
Biopsy may be required to differentiate it from other conditions such as
multinodular goiter and malignancies.

Sarcoidosis involving the thyroid gland in a 34-
year-old woman
(a) US image of the thyroid shows a large heterogeneous nodule in the left thyroid lobe
(arrow). (b) Color Doppler US image shows mild Doppler flow in the left thyroid nodule. A
diagnosis of sarcoidosis was confirmed on the basis of biopsy results. The patient also had a
pulmonary sarcoid (not shown).

Other soft tissue involvement
Cervical adenopathy (CT or MR imaging): Homogenously enhancing
nodes
Carotid artery vasculitis (MR imaging): Abnormal soft-tissue thickening
encasing the carotid vessels

Abdominal and
Pelvic Sarcoidosis
SARCOIDOSIS CAN AFFECT ANY ABDOMINAL ORGAN,
BUT THE LIVER, SPLEEN, PERITONEUM, KIDNEYS, AND
STOMACH ARE MORE COMMONLY AFFECTED

Hepatic sarcoidosis
Hepatic manifestations of sarcoidosis coexist with pulmonary
sarcoidosis, but isolated hepatic disease without thoracic involvement
may develop in up to 13% of patients.
◦ Often asymptomatic
◦ Symptomatic cases (5–15%): Fatigue fever, arthralgia, nonspecific
abdominal pain, jaundice, and pruritus
◦ Long-standing cases: Portal hypertension and cirrhosis

Hepatic sarcoidosis
Ultrasonography (US): Hepatomegaly, heterogeneous liver parenchyma,
and increased liver echogenicity. US also may reveal innumerable small
hypoechoic lesions in 5%–19% of patients
CT imaging: More sensitive than US for identifying these heterogeneous
hypointense nodules, which typically measure only a few millimeters, but
larger lesions may develop, especially when the smaller lesions coalesce.
MR imaging: Hypointense sarcoidosis nodules on T1W & T2W images
◦ Portal system involvement: Areas of increased signal intensity
◦ T2 halo sign: Often reported with biliary cirrhosis or autoimmune hepatitis also
can be seen in patients with hepatic sarcoidosis, manifesting as periportal T2-
hypointense zones surrounding the portal triads that also may show decreased
enhancement after administration of contrast material
Differential diagnosis includes metastases, lymphoma, fungal micro-
abscesses, and mycobacterial infections. When there is doubt regarding the
definitive diagnosis, biopsy may be warranted.

Hepatic sarcoidosis in a 50-year-old man
US image shows numerous small poorly defined hypoechoic lesions (arrows). A diagnosis of
hepatic sarcoidosis was confirmed on the basis of biopsy results. Small hepatic sarcoid
lesions may be difficult to evaluate with US but are often better visualized with CT and MR
imaging.

Hepatosplenic sarcoidosis in a 33-year-old
man
Axial CT image of the abdomen shows many tiny hypointense nodules in the liver (white
arrows), slightly larger hypointense nodules in the spleen (arrowhead), and multiple upper
abdominal nodes (black arrow).

Hepatic sarcoidosis in a 51-year-old woman
(a) Axial T2-weighted MR image shows the T2 “halo sign,” with hypointense periportal zones
(arrows). (b) Axial contrast-enhanced portal venous phase MR image shows poor
enhancement in the periportal regions (arrows). The presence of hepatic sarcoidosis with
prominent tracts of fibrosis along the periportal region was confirmed on the basis of the
biopsy results.

Splenic sarcoidosis
Splenic involvement has been reported in 38%–77% of cases in autopsy
studies
Disease process:
◦ Splenomegaly: Common finding, occurring in 25%–60% of patients
◦ Splenic granulomas: Seen in 6%–33% of patients
Imaging: Appearance of splenic sarcoidosis nodules mimics that of hepatic
sarcoidosis in that the nodules are usually:
◦ Hypoechoic on US images
◦ Hypointense on CT images
◦ Hypointense on T1- and T2-weighted MR images
In general, focal splenic lesions tend to be larger than hepatic foci. Although
sarcoid nodules may show enhancement on delayed phase images, the lack
of peripheral discontinuous nodular enhancement in the early phases may
help to differentiate them from other entities such as hemangiomas.

Splenic sarcoidosis in a 38-year-old woman
(a) US image shows many small hypointense lesions in the spleen (arrows). (b) Axial
contrast-enhanced T1-weighted MR image shows small hypovascular lesions in the spleen
(white arrows) and liver (black arrows). (c) Axial diffusion weighted image with a high b value
(800 sec/mm2) shows many tiny lesions in the spleen (white arrows) and liver (black arrows)
with restricted diffusion.

Splenic sarcoidosis in a 59-
year-old woman
Axial postcontrast CT image shows numerous small hypointense lesions in the spleen (white
arrows). Mild biliary dilatation also is seen (black arrows).

Sarcoidosis involving the esophagus, stomach,
liver, and spleen in a 41-year-old man
Axial contrast-enhanced T1-weighted MR image shows tiny hypovascular lesions in the liver
(white arrows) and spleen (black arrows). Abnormal heterogeneous thickening and
enhancement is also seen in the stomach. A diagnosis of sarcoidosis was confirmed on the
basis of biopsy results.

Pancreatic sarcoidosis
Pancreatic involvement is rare and usually is secondary to invasion from
adjacent peripancreatic adenopathy, rather than isolated primary
pancreatic involvement.
Imaging features: Non-specific and often indistinguishable from
pancreatitis or pancreatic carcinoma, necessitating biopsy for definitive
diagnosis.

Gastrointestinal sarcoidosis
Although any part of the gastrointestinal luminal tract may be affected
in patients with sarcoidosis, the stomach is the most common site of
involvement
Barium studies:
◦ Stomach: Nodular gastric mucosa with irregularly thickened folds, aphthous
ulcers, and polypoid filling defects. Occasionally, a linitis plastica
appearance may be seen with diffuse rigidity of the gastric wall and a
narrowed lumen.
◦ Small bowel and colon: Coarse granular filing defects, mass-like lesions, or
circumferential narrowing of the bowel lumen

Renal sarcoidosis
Autopsy studies report renal involvement in 7%–22% of patients with
sarcoidosis. Renal sarcoidosis typically causes interstitial nephritis with an
infiltrative pattern that tends to preserve the overall reniform shape of the
kidney.
Disease process:
◦ Abnormal calcium metabolism: Results in hypercalcemia (10% cases),
hypercalciuria (30–40% cases), and renal calculi (10% cases)
◦ Underlying renal function usually is maintained, but severe granulomatous
nephritis or substantial intrarenal calcium deposition rarely may result in
renal failure
CT imaging:
◦ Hypovascular lesions causing a range of enhancement patterns (from
mottled or striated to the less frequently seen mass-like areas
◦ Nephromegaly, atrophy, or multifocal bilateral hypointense
hypovascular masses

Renal sarcoidosis in a 42-year-old man
Axial CT image of the abdomen shows many hypoattenuating lesions in the kidneys
(arrowheads) bilaterally. Upper abdominal adenopathy (arrows) is also present. Conditions
considered in the differential diagnosis included metastases, lymphoma, pyelonephritis,
interstitial nephritis, and immunoglobulin G4–related renal disease. A diagnosis of sarcoidosis
was confirmed on the basis of biopsy results

Other sites
Testicular sarcoidosis: Multiple unilateral or bilateral hypoechoic lesions
in the testes and epididymis on ultrasonography
Abdominal & pelvic adenopathy (seen in 30% cases): Any nodal station
may be involved, but upper abdominal nodes are more commonly
involved compared to pelvic nodes.
Peritoneal sarcoidosis: Nonspecific imaging findings (ascites, diffuse
peritoneal stranding, or discrete focal peritoneal nodules)

Testicular sarcoidosis in a 33-year-old man
Longitudinal US image of the right testicle shows scattered hypoechoic lesions (arrows).
Lesions with a similar appearance were also seen in the left testicle (not shown). The patient
had a known diagnosis of sarcoidosis, and concurrent CT of the chest showed bilateral hilar
adenopathy, consistent with multisystem sarcoid involvement.

Sarcoidosis in a 62-year-old woman
Axial fused PET/CT images of the pelvis show a markedly FDG-avid mass in the pelvis,
which is confluent with bulky left external iliac adenopathy (arrow in a), and an FDG-avid
inguinal node (arrow in b). A diagnosis of sarcoidosis was confirmed on the basis of biopsy
results.

Peritoneal sarcoidosis in a 47-year-old man
Axial contrast-enhanced T1-weighted MR image shows nodular thickening and enhancement
in the peritoneum (arrows). This appearance is nonspecific because peritoneal
carcinomatosis, peritoneal lymphomatosis, and infectious conditions such as tuberculosis
also may cause a similar appearance. A diagnosis of peritoneal sarcoidosis was confirmed on
the basis of biopsy results.

Musculoskeletal
Sarcoidosis
SARCOIDOSIS CAN INVOLVE THE BONES, JOINTS, AND
MUSCLES.

Osseous sarcoidosis: Small bones
Osseous involvement in sarcoidosis occurs in 1%–13% of patients, with
an estimated average occurrence of 5%.
Small bones of the hand: In particular, the distal and middle phalanges
of the second and third digits are involved more commonly
◦ Sausage dactylitis: Soft-tissue thickening surrounding the fingers
Radiography:
◦ Lace-like pattern of osteolysis with thickened trabeculae and a thin cortex
(characteristically seen in the small bones of the hands and feet)
◦ Periosteal reaction is typically absent
◦ Pathologic fractures with bone collapse and misalignment due to sarcoid
osteolysis

Osseous sarcoidosis in a 43-year-old man
Radiograph of the left hand shows lace-like osteolysis in the phalanges, with multiple well-
defined lytic lesions (arrows). Note the preservation of joint space and the absence of
periosteal reaction.

Osseous sarcoidosis: Long bones
Sarcoid involvement of the long bones of the extremities and axial
skeleton is relatively uncommon.
Radiography and bone scintigraphy may not be sensitive for identifying
sarcoid involvement at these sites
CT imaging: Lytic lesions with or without peripheral sclerosis
MR imaging: Well-defined, focal T1-hypointense, T2-hyperintense, and
enhancing intramedullary lesions or poorly defined infiltrative
processes in the bone marrow

Osseous sarcoidosis in a 57-year-old man
(a) Sagittal T1-weighted MR image shows a large hypointense intramedullary lesion in the left tibia (arrow). A
smaller lesion is seen superior to this. (b) Sagittal short inversion-time inversion-recovery (STIR) MR image
shows heterogeneous high signal intensity in the lesion (arrow). (c) Sagittal fat suppressed contrast-
enhanced T1-weighted MR image shows avid enhancement in the intramedullary lesions (arrow). A diagnosis
of sarcoidosis was confirmed on the basis of biopsy results.

Sarcoidosis in a 62-year-old woman
(a) Sagittal T1-weighted MR image of the lumbar spine shows numerous T1-hypointense lesions (arrows) in
the lumbar vertebrae. (b) Sagittal short inversion time inversion-recovery (STIR) MR image of the lumbar
spine demonstrates T2-hyperintense lesions (arrow) in the lumbar spine. Biopsy of the bone lesion confirmed
sarcoidosis.

Acute sarcoid arthritis
Sarcoid involvement of the joints is relatively common and is classified as
acute arthritis or chronic or recurrent arthritis. Sarcoid arthritis tends to be
more common in young women (<40 years old).
The acute phase may manifest in 10%–40% of cases. Usually, it is seen early
in the course of the disease (within 6 months of diagnosis) and is typically
self limiting.
Clinical presentation: Polyarthritis or oligoarthritis is much more common
than is monoarthritis.
◦ Common sites: Ankles, knees, wrists, proximal interphalangeal joints,
metacarpophalangeal joints, and elbows
◦ Presenting symptoms: Swelling, pain, erythema, tenderness, and reduced
mobility and range of motion
◦ Löfgren syndrome: Acute sarcoidosis characterized by the combination of
erythema nodosum, bilateral hilar adenopathy, polyarthritis, and constitutional
symptoms

Chronic sarcoid arthritis
When the symptoms of sarcoid arthritis have persisted more than 6
months after the diagnosis of sarcoidosis, it is considered chronic
sarcoid arthritis.
In comparison with acute arthritis, the chronic form is seen
infrequently, manifesting in 1%–4% of patients. Patients may develop
oligoarthritis involving the ankles or knees. Symptoms may recede, but
recurrence is not uncommon.
MR imaging: Significant arthritis with concurrent abnormalities such as
tenosynovitis, tendonitis, bursitis, and synovitis

Muscular involvement
Asymptomatic muscular involvement may develop in 25–80% of
patients with sarcoidosis. Symptomatic involvement is rare (< 0.5%
cases) and presents with:
◦ Acute myositis: Fever, myalgia, muscle weakness
◦ Nodular sarcoidosis: Palpable nodules that may be painful or tender
◦ Chronic myopathy: Proximal muscle weakness, muscle atrophy, muscle
contractures
◦ Respiratory muscle involvement: Dyspnea
MR imaging:
◦ Nodular sarcoid myopathy: Single or multifocal soft-tissue masses, often
involving the lower extremities
◦ Dark star appearance: Lesions may have a star-shaped area of low signal
intensity in the center and high signal intensity in the periphery on T2-
weighted images

Subcutaneous involvement
On imaging, subcutaneous involvement appears as local or diffuse
infiltrative lesions.
◦ Ultrasonography (US): Hypoechoic lesions
◦ CT imaging: Soft tissue-attenuation nodules
◦ MR imaging: T1 hypointense compared with muscle and T2 hyperintense,
with mild enhancement on postcontrast images

Cutaneous
Sarcoidosis
THERE IS A SPECTRUM OF CUTANEOUS
MANIFESTATION IN SARCOIDOSIS THAT MAY
DEVELOP IN 20%–35% OF PATIENTS

SPECIFIC LESIONS
Maculopapule, nodule, plaque,
subcutaneous nodule, infiltrative
scar, and lupus pernio
◦ Papules (most common
manifestations): Tiny flesh-colored,
red, or yellow lesions seen around
the eyes and nasolabial folds and in
the head and neck regions
◦ Lupus pernio (most characteristic
specific cutaneous manifestation of
sarcoidosis): Reddish-purple plaques
associated with prominent
telangiectasia and typically are seen
in the nose, ear, cheek, and hand
NON-SPECIFIC LESIONS
Erythema nodosum; calcifications;
prurigo; erythema multiforme; and
nail changes (clubbing, onycholysis,
and subungual hyperkeratosis)
◦ Erythema nodosum (nonspecific
lesion due to hypersensitivity
reaction to a hitherto unknown
antigen): Tender erythematous
subcutaneous nodules on the shin
and are usually associated with acute
sarcoidosis

Löfgren syndrome
Classic clinical presentation of sarcoidosis, thought to be virtually
diagnostic for sarcoidosis, obviating the need for histopathologic
confirmation.
It comprises of the following:
1. Erythema nodosum
2. Bilateral hilar adenopathy
3. Acute sarcoid arthritis
4. Fever

Sarcoid-like
reactions
SARCOID REACTIONS OR SARCOID-LIKE REACTIONS REFER TO THE
MANIFESTATION OF NONCASEATING GRANULOMAS IN PATIENTS WITH
KNOWN MALIGNANCIES, WHICH CAN DEVELOP IN THE REGIONAL LYMPH
NODES THAT DRAIN A TUMOR SITE, IN THE TUMOR ITSELF, OR AT OTHER
SITES, WITHOUT THE SYSTEMIC MANIFESTATIONS OF SARCOIDOSIS.

Sarcoid-like reactions
Sarcoid reactions can develop during chemotherapy or immunotherapy
and may cause substantial confusion, because they could be
misconstrued to be progressive or recurrent disease.
Similar to malignancies, sarcoid-like reactions also can demonstrate
uptake of FDG at PET/CT, which can make it extremely difficult to
differentiate between these two entities. Awareness of the pattern of
FDG uptake in sarcoid reactions may help to avoid misinterpretation of
these as progressive disease, but tissue diagnosis may be necessary in
most cases for definitive confirmation.

Sarcoid-like reaction in a 38-year-old woman
with melanoma who was undergoing
immunotherapy.
Axial fused PET/CT images show FDG-avid bilateral hilar adenopathy (arrows in a),
numerous focal splenic lesions (arrow in b), and upper abdominal nodes (arrows in c).
Although this pattern of symmetrical hilar adenopathy with splenic and upper abdominal nodal
involvement is suggestive of a sarcoid-like reaction, the differential diagnosis would include
evaluation for recurrent disease. The results of pathologic analysis showed the presence of
noncaseating granuloma and were negative for tumor cells.

Management
CURRENTLY AVAILABLE TREATMENT OPTIONS ARE
NOT CURATIVE, BUT RATHER ARE AIMED AT
CONTROLLING THE GRANULOMATOUS PROCESS.

Treatment
Early-stage pulmonary sarcoidosis: Observation without specific
treatment (due to high probability of spontaneous resolution)
Systemic treatment: Indicated in extrapulmonary diseases such as
cardiac, central nervous system, renal, ocular, and cutaneous
sarcoidosis (those that do not respond to topical therapy) and
symptomatic hypercalcemia. Patients should be monitored closely for
adverse effects, given the high toxicity of these treatment regimens.
◦ Systemic corticosteroids (mainstay)
◦ Immunosupressants (steroid resistant cases): Antimalarial drugs,
tetracycline, methotrexate, azathioprine, leflunomide, cyclophosphamide,
mycophenolate mofetil, pentoxifylline, infliximab, rituximab, and
adalimumab
Advanced-stage disease (the lungs, liver, heart, or kidneys): Organ
transplantation

Follow-up
Although no strict guidelines currently are available for follow-up, there
are a few general suggestions.
Every 3–6 months: Clinical examination and chest radiography
Every 6 months: Pulmonary function tests, electrocardiography, and
checking of serum creatinine and calcium levels
Patients who demonstrate response to steroid therapy should be
monitored and followed up for at least 3 years because approximately
37–74% of treated patients show relapse within that time period.

Conclusion
SARCOIDOSIS CAN AFFECT MULTIPLE ORGAN SYSTEMS
IN THE BODY. CLINICAL MANIFESTATIONS USUALLY ARE
NONSPECIFIC, WHICH CAN LEAD TO DELAYED
DIAGNOSIS. THIS IS WHERE A RADIOLOGIST COMES IN.

Conclusion
Radiologists should be aware of the imaging features of both pulmonary
and extrapulmonary sarcoidosis. Radiologists play an important role in
the management of sarcoidosis.
◦ A radiologist may be the first person to suggest this diagnosis on the basis of
imaging features, even when the diagnosis is not clinically suspected
◦ In patients with characteristic clinical features suggestive of sarcoidosis such
as Löfgren’s syndrome, the presence of classic imaging findings may help to
confirm the diagnosis.
◦ Finally, imaging is increasingly being used for monitoring therapeutic
response and identifying complications related to sarcoidosis.
Therefore, familiarity with the imaging features of sarcoidosis may help
in diagnosing, evaluating the extent of disease, and guiding optimal
patient care.

Sarcoidosis from head to toe: What the radiologist needs to know

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