Papillary intralymphatic angioendothelioma of the spleen in a young adult: case report and literature review.

Background: Papillary intralymphatic angioendothelioma (PILA) is a rare low-grade malignant vascular tumor, typically occurring in the skin and subcutaneous tissues of children. Primary splenic involvement is extremely uncommon. Its imaging features often resemble those of benign splenic lesions such as hemangioma or hamartoma, leading to frequent misdiagnosis. This case highlights the diagnostic challenge and emphasizes the importance of considering PILA in the differential diagnosis of splenic masses, particularly in young patients, due to its potential for local recurrence. Case presentation: A 21-year-old male presented with a 2-month history of mild left upper abdominal heaviness. He had no fever, pain, trauma history, or hematologic disorders. Systemic symptoms were absent, and tumor markers were normal. Enhanced abdominal CT and MRI revealed a solitary, large heterogeneous mass occupying most of the spleen, initially suggestive of hemangioma or hamartoma. The patient underwent laparoscopic total splenectomy. Following resection, the normal splenic tissue was fragmented into approximately 2 × 2 cm pieces and autotransplanted into the omentum. Final histopathological examination confirmed primary splenic PILA. The postoperative course was uneventful, and the patient was discharged after one week. He remained disease-free at 6-month follow-up. Conclusions: This report illustrates that PILA, though rare, should be included in the differential diagnosis of solitary vascular splenic masses in young adults. Accurate diagnosis is crucial as PILA possesses a propensity for local recurrence, guiding appropriate surgical management and postoperative surveillance to prevent disease progression.