Splenic lymphangioma is a rare benign lymphatic malformation of the spleen consisting of dilated lymphatic channels lined by endothelium. It is considered to result from congenital lymphatic developmental anomaly (obstruction or agenesis of the lymphatic drainage system) and is regarded as a hamartoma or malformation rather than a true neoplasm. Histopathologically, it consists of thin-walled, anastomosing lymphatic spaces lined by single-layer flat endothelium; immunohistochemical D2-40 (podoplanin) positivity is diagnostic for lymphatic endothelium. Lesions are typically multiloculated cystic structures containing thin septa; contents are serous-chylous (proteinaceous, lymphatic fluid) or serous. Most patients are asymptomatic and discovered incidentally; large lesions may develop left upper quadrant pain, splenomegaly, or rarely rupture and hemoperitoneum. More common in children and young adults. Generalized lymphangiomatosis syndrome may involve multiple organs (liver, bone, lung). There is no risk of malignant transformation. Treatment is generally symptomatic or surgical (splenectomy or partial splenectomy) for large lesions.
Age Range
1-40
Peak Age
20
Gender
Equal
Prevalence
Rare
Splenic lymphangioma results from failure of lymphatic channels to connect with the normal splenic lymphatic drainage system during embryonic development, or from local obstruction of the lymphatic system. This congenital drainage disorder leads to progressive dilation of lymphatic channels — lymph fluid accumulates within channels creating progressively enlarging multiloculated cystic spaces. Histologically, three subtypes are recognized: (1) capillary lymphangioma (small, dermal lymphatic channels), (2) cavernous lymphangioma (large, irregular lymphatic spaces — most common in spleen), and (3) cystic hygroma (very large, macrocystic spaces). The contents of lymphatic spaces are protein-rich lymph fluid (higher protein concentration than pure water) — this protein content is reflected on CT as slightly higher density than water and on T1-weighted MRI as mild signal increase compared to pure water. On T2-weighted MRI, the high free water content of lymphatic fluid creates marked hyperintensity — long T2 relaxation time of fluid-filled spaces results in high signal. Thin septa contain fibrous connective tissue and smooth muscle fibers — these septa show mild enhancement on contrast-enhanced imaging because they harbor their own capillary networks. The absence of fenestrations in lymphatic endothelium (unlike vascular endothelium) prevents contrast agent passage into cystic spaces — therefore cyst contents show no enhancement (similar to simple cysts).
The honeycomb pattern formed by regular, thin echogenic septa within a multiloculated anechoic cystic lesion in splenic parenchyma on US is characteristic for lymphangioma. This pattern helps differentiation from simple cysts (unilocular, no septa) and hydatid cysts (thick laminar membrane, irregular septa).
On unenhanced CT, a well-defined, multiloculated, hypodense cystic lesion is seen in the splenic parenchyma. Density typically ranges between 10-20 HU — near water density (0 HU) but may be slightly higher due to proteinaceous lymphatic fluid content. Thin septa may be seen between hypodense cystic contents but are difficult to detect on unenhanced phase. Large lesions may occupy most of the splenic parenchyma. Calcification may rarely be seen in septa or cyst wall. Surrounding splenic parenchyma shows normal density and may demonstrate compression effects.
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A well-defined, multiloculated, near-water density hypodense cystic lesion is seen in the spleen on unenhanced CT.
On portal venous phase, thin septa show mild enhancement but cystic cavity contents do not enhance — confirming simple cystic nature. Septal enhancement represents the vascular component from capillary networks within septa. Cyst wall is thin and smooth without thickening or nodularity. Absence of solid component or papillary projection is important for differentiation from malignant cystic tumors. In large lesions, splenic parenchyma is compressed and a 'rim' of normal splenic tissue may be seen around the lesion.
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The splenic cystic lesion shows thin septal enhancement without enhancement of cyst contents; no solid component or wall nodularity is seen.
On T2-weighted MRI, the lesion shows markedly hyperintense (bright) signal — the long T2 relaxation time of fluid-filled lymphatic spaces results in high signal intensity. The multiloculated structure is seen as multiple hyperintense cystic compartments between thin hypointense septa. Signal intensity is close to CSF or bladder fluid. In compartments with increased protein content, T2 signal may be slightly lower (proteins shorten T2 relaxation). T2 signal heterogeneity (blood products) may be seen in compartments with hemorrhagic complication. Surrounding splenic parenchyma shows normal homogeneous signal.
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The splenic lesion demonstrates markedly hyperintense multiloculated cystic structure on T2W MRI with distinguishable thin hypointense septa.
On T1-weighted MRI, the lesion shows hypointense or low-intermediate signal relative to splenic parenchyma. Compartments containing pure serous fluid show marked T1 hypointensity, while compartments with proteinaceous or chylous fluid may show intermediate signal — protein exhibits T1-shortening effect. T1 hyperintense foci may be seen in hemorrhagic compartments due to methemoglobin presence. On post-gadolinium contrast-enhanced T1 sequences, thin septa mildly enhance but cyst contents do not — an important finding confirming simple cystic nature.
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The splenic lesion shows hypointense signal on T1W MRI with mild enhancement of thin septa on contrast-enhanced sequences.
On B-mode ultrasonography, a well-defined, multiloculated, anechoic or hypoechoic cystic lesion is seen in the spleen. Characteristically, thin echogenic septa divide the cystic spaces — creating a 'honeycomb' pattern. Posterior acoustic enhancement is prominent (fluid-filled structure). Septa are generally smooth, thin (<2 mm) without thickening. Low-level internal echoes may be seen in compartments with proteinaceous or chylous fluid. No solid component, papillary projection, or thick/irregular septa — these features support simple cystic nature. Large lesions may deform the splenic contour.
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A well-defined, multiloculated, anechoic cystic lesion is seen in the spleen on US with thin septa and posterior acoustic enhancement.
The lesion shows no diffusion restriction on DWI — signal loss at high b-values with high signal on ADC maps. ADC values are generally >2.5 × 10⁻³ mm²/s, close to pure fluid. This finding supports simple cystic nature and is important for differentiation from abscess (viscous purulent content with diffusion restriction) or solid tumors. T2 shine-through effect at high b-values (b=800-1000) may create false impression of diffusion restriction — must be confirmed with ADC maps.
Report Sentence
The splenic cystic lesion shows no diffusion restriction on DWI with high signal on ADC maps supporting simple cystic nature.
Criteria
Composed of small, thin lymphatic channels. Usually dermal/subcutaneous location, rare in spleen. Histologically capillary-sized lymphatic channels.
Distinct Features
Microcystic pattern on imaging — numerous very small cystic spaces. 'Spongy' echo pattern on US.
Criteria
Composed of large, irregular lymphatic spaces. Most common type in spleen. Multiloculated macrocystic structure separated by thin septa.
Distinct Features
Classic honeycomb pattern. Multiloculated cystic structure most prominently seen on US/MRI/CT. Thin septa enhance.
Criteria
Very large, macrocystic spaces. Usually in neck/axilla, very rare in spleen. May be seen in generalized lymphangiomatosis.
Distinct Features
Single large cystic space or few large compartments. Septa less prominent. Extensively displaces splenic parenchyma.
Distinguishing Feature
Simple cyst is unilocular, no septa, smooth thin wall. Lymphangioma is multiloculated with thin septa. Simple cyst has epithelial lining (true cyst), lymphangioma has endothelial lining.
Distinguishing Feature
Pseudocyst with trauma history, thick fibrous wall, eggshell calcification common. Lymphangioma has thin wall, thin septa, calcification rare. Pseudocyst unilocular, lymphangioma multiloculated.
Distinguishing Feature
Abscess shows diffusion restriction on DWI (viscous purulent content), lymphangioma does not. Abscess has thick irregular wall with rim enhancement, clinical fever/leukocytosis accompanies.
Distinguishing Feature
Hemangioma shows peripheral nodular enhancement with centripetal fill-in (vascular pattern). Lymphangioma has septal enhancement but cyst contents do not enhance (cystic pattern). Hemangioma generally solid or spongy, lymphangioma cystic.
Urgency
routineManagement
conservativeBiopsy
Not NeededFollow-up
12-monthSplenic lymphangioma is a benign lesion without malignant transformation risk. No treatment needed for asymptomatic small lesions — annual US follow-up is sufficient. Surgery (splenectomy or partial splenectomy) is planned for large, symptomatic, or growing lesions. Rupture or infection complications may require emergent surgery. Comprehensive imaging (CT chest/abdomen) is recommended when generalized lymphangiomatosis is suspected. Closer follow-up may be needed in children due to growth potential.
Splenic lymphangioma is benign with no malignant transformation risk. Follow-up is sufficient in asymptomatic cases. Splenectomy or partial splenectomy may be considered for symptomatic or large lesions. May be associated with diffuse lymphangiomatosis syndrome (multiple organ involvement).