Littoral Cell Angioma of the Spleen: A Case Report.

Littoral cell angioma (LCA) is a rare, primary vascular tumor of the spleen that originates from the cells lining the venous sinuses of the spleen. Around 150 cases have been reported worldwide, with most reported cases of LCA being non-malignant but with unspecified malignant potential. As of 2022, three cases of malignant LCA have been reported. A 75-year-old male with a history of monoclonal gammopathy of uncertain significance presented with left upper outer quadrant abdominal pain. Ultrasound (US) scan showed a 10.5 cm round, circumscribed mass lesion, with hyperechoic foci, occupying the posterolateral aspect of the spleen. US-guided core needle biopsy of the mass revealed a diagnosis of "atypical cells present, suggestive of vascular neoplasm of the spleen," which was based on histologic and immunohistochemistry characteristics. Due to the size of the lesion, a malignant neoplasm was suspected, and a splenectomy was performed. Histological and immunohistochemical features of the splenic lesion returned a final diagnosis of benign LCA.