Splenic Marginal Zone Lymphoma as a Vascular-Appearing Mass in a Patient With Sustained Virologic Response to Hepatitis C Therapy.

BACKGROUND Splenic marginal zone lymphoma (SMZL) is a low-grade B-cell lymphoma associated with chronic hepatitis C infection. It typically presents with diffuse splenomegaly rather than a focal splenic mass. Focal splenic lesions with vascular enhancement patterns are usually due to vascular tumors which may be benign or malignant, examples of which include sclerosing angiomatoid nodular transformation, hemangiomas, or angiosarcomas. CASE REPORT A 60-year-old man with newly diagnosed hepatitis C-related Child-Pugh A cirrhosis was incidentally found to have a splenic lesion during index abdominal imaging. He was initiated on hepatitis C treatment and successfully achieved a sustained virologic response. Despite viral eradication, serial imaging over 3 years demonstrated a sudden increase in size from 3.3 cm to 5.7 cm. Multiphasic computed tomography (CT) of the abdomen demonstrated a progressive peripheral-to-central enhancement pattern, mimicking a vascular splenic tumor. A review by a multidisciplinary tumor board recommended splenectomy due to progressive enlargement, rupture risk, and inability to exclude a malignant lesion. Histopathological examination revealed SMZL with extensive central infarction and granulomatous reaction, confirming the diagnosis with characteristic biphasic architecture and CD20-positive B-cell populations. No features of aggressive transformation were identified. CONCLUSIONS Our case highlights an unusual presentation of SMZL as a focal splenic mass, rather than diffuse splenomegaly, which grew despite hepatitis C eradication. Tumor infarction and slow organization can produce radiologic features that mimic vascular splenic lesions. This demonstrates the importance of clinicoradiological-pathological correlation and the necessity of histological confirmation in indeterminate splenic masses to avoid delays in management.