Retroperitoneal lymphangioma is a rare, benign cystic lesion arising from congenital malformation of lymphatic channels. Approximately 5% of all lymphangiomas are retroperitoneal. Typically detected in children and young adults; large lesions may cause abdominal pain or palpable mass. Histologically consists of endothelium-lined, dilated lymphatic channels and thin fibrous septa; contains chylous or serous fluid. Appears on CT as a thin-walled, thin-septated, multiseptate cystic mass. On MRI shows markedly hyperintense signal on T2, hypointense (serous) or hyperintense (chylous/hemorrhagic) on T1. Surgical excision is curative but complete resection may be difficult and recurrence rate is 10-15%.
Age Range
1-50
Peak Age
30
Gender
Equal
Prevalence
Rare
Retroperitoneal lymphangioma is a congenital lymphatic malformation resulting from failure of lymphatic channels to establish normal connection with the venous system during embryonic development. Lymphatic channels dilate and form multiple cystic spaces lined by thin endothelium. Cyst contents are protein-rich lymphatic fluid (chylous) or serous fluid; chylous content is related to intestinal lymphatic drainage. The near-water density cystic structure on CT results from the low protein concentration fluid having X-ray attenuation similar to water; fat density areas may be seen in chylous content. T2 hyperintensity on MRI is due to the high free water content of cyst fluid — long T2 relaxation time produces high signal. T1 signal varies with cyst content: serous fluid is hypointense, chylous fluid (due to lipid droplets) is hyperintense, hemorrhagic fluid (methemoglobin) is hyperintense. Thin septa represent lymphatic channel walls and intervening connective tissue.
Markedly hyperintense, thin-septated, multiloculate cystic mass on T2-weighted MRI — septa hypointense on T2, show minimal post-contrast enhancement. Combined with absence of solid component, characteristic for lymphangioma diagnosis.
On non-contrast CT, a thin-walled (<2 mm), thin-septated, multiloculate cystic mass in the retroperitoneal space. Cyst contents show water density (0-20 HU) or slightly negative density (-10 to 0 HU) in chylous content. No calcification. Displaces but does not invade adjacent structures.
Report Sentence
A thin-walled, multiloculate, water density cystic mass is seen in the retroperitoneal space; consistent with retroperitoneal lymphangioma.
Markedly hyperintense, multiloculate cystic mass on T2-weighted images. Thin septa are seen as hypointense linear structures on T2. Cyst locules show uniform T2 hyperintensity — signal may be heterogeneous in hemorrhagic foci. Markedly hyperintense signal is also preserved on STIR.
Report Sentence
The retroperitoneal mass shows markedly hyperintense signal on T2-weighted sequence, and the thin-septated multiloculate cystic structure is consistent with lymphangioma.
On T1-weighted images, cyst locules show variable signal depending on content: serous fluid hypointense, chylous fluid hyperintense (lipid component), hemorrhagic fluid hyperintense (methemoglobin). Post-contrast thin linear enhancement of cyst wall and septa; no solid nodular enhancement.
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Cyst locules show variable signal on T1 sequence — hyperintense areas consistent with chylous/hemorrhagic component are present; septa show thin post-contrast enhancement.
Post-contrast CT shows thin septa and cyst wall with minimal enhancement. Cyst contents do not enhance. No solid nodular enhancing component — evaluated in favor of benign cystic lesion. Septa thickness <2 mm is maintained.
Report Sentence
Post-contrast thin septa and cyst wall show minimal enhancement; cyst contents do not enhance and no solid component is seen.
On US, anechoic or mildly echogenic content, thin-septated, multiloculate cystic mass. Posterior acoustic enhancement confirms cystic nature. Thin septa may show vascularity on Doppler. No solid component.
Report Sentence
An anechoic, thin-septated, multiloculate cystic mass is seen in the retroperitoneal space; posterior acoustic enhancement is present — consistent with lymphangioma.
Cyst contents show no diffusion restriction on DWI — ADC values are high. This confirms simple fluid content and distinguishes from lesions showing diffusion restriction such as abscess or solid neoplasm. Septa may not be visualized on DWI.
Report Sentence
Cyst contents show no diffusion restriction on DWI; consistent with simple cystic fluid and abscess has been excluded.
Criteria
Composed of small, thin-walled lymphatic channels. Usually small in size. Requires histological subtyping.
Distinct Features
Microcystic structure on imaging, very small locules.
Criteria
Composed of dilated lymphatic channels. Medium-sized cystic spaces. Most common histological type.
Distinct Features
Multiloculate cystic structure on CT/MRI, medium-sized locules, thin septa.
Criteria
Large cystic spaces (>2 cm locules). Usually in children. Neck and axilla most common location, retroperitoneal rare.
Distinct Features
Large, few locules, thin septa; large cystic mass at water density on CT.
Distinguishing Feature
Mesenteric cyst is usually unilocular and without septa; lymphangioma is multiloculate with thin septa. Both are thin-walled and at water density.
Distinguishing Feature
Schwannoma is a solid mass, shows target sign on T2 and enhances; lymphangioma is cystic, multiloculate and does not enhance (except septa).
Distinguishing Feature
Abscess is thick-walled, shows rim enhancement and prominent diffusion restriction on DWI; lymphangioma is thin-walled, no diffusion restriction.
Distinguishing Feature
Paraganglioma is a solid, hypervascular mass with intense enhancement; lymphangioma is cystic, non-enhancing.
Urgency
routineManagement
surgicalBiopsy
Not NeededFollow-up
12-monthRetroperitoneal lymphangioma is a benign lesion. Conservative approach and annual follow-up may be applied for asymptomatic lesions. Surgical excision is recommended for symptomatic or growing lesions; however, complete resection may not always be possible due to adhesions to adjacent structures and recurrence rate is 10-15% after incomplete resection. Sclerotherapy (bleomycin, OK-432) is an alternative treatment option. Malignant transformation has not been reported.
Retroperitoneal lymphangiomas are benign lesions. Surgical resection is curative but complete resection may be difficult due to insinuating growth. Recurrence after incomplete resection occurs in 10-15% of cases. There is no risk of malignant transformation. Sclerotherapy may be an alternative treatment.