Splenic sarcoidosis is the involvement of the spleen by non-caseating granulomatous inflammation. Splenic involvement occurs in 24-59% of patients with systemic sarcoidosis, but detectable focal lesions on imaging are less common (6-15%). Typically presents as multiple small hypoechoic/hypodense nodules. Absence of necrosis is an important distinguishing feature from infectious granulomatous diseases (tuberculosis, fungal). Sarcoid granulomas are compact, well-organized, composed of epithelioid histiocytes and giant cells without central necrosis. Splenomegaly may be present.
Age Range
20-60
Peak Age
35
Gender
Female predominant
Prevalence
Uncommon
Sarcoidosis is a systemic granulomatous disease resulting from an exaggerated immune response to unknown antigenic stimuli. Activated CD4+ T-lymphocytes and macrophages form non-caseating granulomas. In the spleen, these granulomas accumulate in red and white pulp, displacing normal splenic tissue. Granulomas consist of compact epithelioid histiocyte clusters and multinucleated giant cells; central necrosis is ABSENT — this feature fundamentally distinguishes sarcoidosis from tuberculosis and fungal granulomas. On imaging, they appear as multiple small hypodense/hypoechoic nodules because granulomatous tissue has different vascularity and cellular composition from surrounding normal splenic parenchyma — granulomas are avascular, do not enhance, and show lower density than surrounding tissue. Splenomegaly develops with diffuse involvement as granulomas accumulate in splenic sinusoids, obstructing blood flow and increasing splenic volume.
Multiple small (usually <2 cm) hypodense/hypoechoic nodules scattered in splenic parenchyma on portal venous phase CT or US — homogeneous structure without necrosis, calcification, or hemorrhagic component. Also described as 'starry sky' pattern. When seen together with bilateral hilar lymphadenopathy, strongly suggests sarcoidosis diagnosis.
Multiple small (usually <2 cm, most 5-10 mm) hypodense nodules in portal venous phase. Homogeneous internal structure, no necrosis or calcification. Nodules show distinctly lower density compared to surrounding splenic parenchyma. Number can range from a few to dozens.
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Multiple small hypodense nodules are seen in the spleen, their non-necrotic nature consistent with sarcoidosis involvement.
Increased spleen size on non-contrast CT (craniocaudal length >13 cm). In diffuse involvement, no focal lesion may be detected in parenchyma; only homogeneous splenomegaly may be seen. Nodules may be isointense on non-contrast CT and can be missed.
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Increased spleen size (craniocaudal ... cm) is noted, suggesting sarcoidosis-related splenomegaly in the clinical context.
Multiple small hypoechoic nodules on US. Generally round/oval, well-defined. Homogeneous internal structure — no necrotic component or cystic area. Lesions with distinctly decreased echogenicity compared to surrounding splenic parenchyma, but not completely anechoic (solid in nature).
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Multiple small hypoechoic solid nodules are seen in the spleen, their non-necrotic nature consistent with granulomatous disease (sarcoidosis).
Nodules are avascular on Doppler US — no internal vascularity. While surrounding splenic parenchyma shows normal vascular pattern, no flow is detected within granulomatous nodules. This finding supports that solid nodules are not neoplastic.
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Splenic nodules show avascular character on Doppler examination, consistent with granulomatous etiology.
Multiple nodules hypointense relative to splenic parenchyma on T2-weighted images. Sarcoid granulomas show low signal on T2 due to fibrotic component and low free water content. This finding differs from tuberculosis granulomas — TB granulomas may be more heterogeneous on T2 due to necrotic center.
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Multiple nodules hypointense relative to splenic parenchyma on T2-weighted images, consistent with sarcoidosis granulomas.
Isointense or mildly hypointense nodules relative to splenic parenchyma on T1-weighted images. T1 contrast is limited — nodules may be difficult to detect on non-contrast T1. Post-gadolinium enhancement is minimal or absent.
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Isointense/mildly hypointense nodules relative to splenic parenchyma on T1-weighted images, showing no enhancement.
Splenic nodules show increased FDG uptake on FDG PET-CT. Active granulomatous inflammation is metabolically active and FDG-avid. Diffuse splenic involvement may show homogeneous increased spleen FDG uptake. SUVmax is generally moderate (3-8). PET is used for treatment response assessment.
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Nodules/diffuse uptake with increased FDG uptake in the spleen on FDG PET-CT, consistent with active granulomatous disease.
Criteria
Detectable focal nodules present in spleen. Usually multiple, small (<2 cm), hypoechoic/hypodense. Seen in 6-15% of patients. Easily detected on CT and US.
Distinct Features
Focal lesions detectable, multiple small nodules, non-necrotic, homogeneous, follow-up and treatment response easily assessable
Criteria
Presents with splenomegaly only without detectable focal lesions. Granulomas are microscopically diffusely distributed. Only homogeneous spleen enlargement detected on imaging. More common (33-60%).
Distinct Features
No focal lesion, only splenomegaly, specific diagnosis difficult by imaging alone, clinical/laboratory correlation mandatory
Criteria
Rare variant — few large (>2 cm) nodules or mass formation. May be confused with lymphoma or metastasis. May require biopsy. Large masses form due to coalescent granulomas.
Distinct Features
Large mass formation (>2 cm), rare, may be confused with lymphoma/metastasis, biopsy usually required
Distinguishing Feature
Lymphoma generally forms larger nodules/masses with more aggressive course. May show higher SUVmax on FDG PET. In sarcoidosis bilateral hilar LAP + lung involvement is prominent, while widespread abdominal/retroperitoneal LAP is expected in lymphoma. B symptoms (fever, night sweats, weight loss) are more prominent in lymphoma.
Distinguishing Feature
Metastases usually accompany known primary malignancy and may show heterogeneous enhancement, necrosis. In sarcoidosis necrosis is ABSENT and nodules are homogeneously hypodense. Metastases show more size variability. Accompanying bilateral hilar LAP and elevated ACE in sarcoidosis are distinguishing.
Distinguishing Feature
Infectious granulomas (TB, fungal) contain caseating necrosis — show central low density or calcification on CT. Sarcoidosis granulomas are NON-CASEATING so necrosis is absent and they are homogeneous. TB granulomas show rim enhancement, sarcoidosis has no enhancement. Clinical context: fever, epidemiological risk in TB; bilateral hilar LAP in sarcoidosis.
Distinguishing Feature
Abscess shows central liquefactive necrosis, rim enhancement and perisplenic inflammation. In sarcoidosis there is no necrosis or rim enhancement, nodules are homogeneously hypodense. Clinical: high fever, leukocytosis, acute presentation in abscess; chronic course, elevated ACE in sarcoidosis.
Urgency
routineManagement
medicalBiopsy
Not NeededFollow-up
6-monthSplenic sarcoidosis is generally evaluated as a component of systemic sarcoidosis and does not require isolated treatment. Systemic corticosteroid therapy (prednisone) also regresses splenic involvement. For asymptomatic splenic involvement, follow-up alone may be sufficient. Treatment is intensified for symptomatic splenomegaly, cytopenia, or splenic complications (spontaneous rupture — very rare). PET-CT is used for treatment response assessment. Splenectomy is rarely required (refractory cytopenia, splenic rupture).
Splenic sarcoidosis is usually part of systemic disease and does not require isolated treatment. Splenomegaly may lead to hypersplenism. Response to steroid therapy is possible.