Primary splenic angiosarcoma initially diagnosed as littoral cell angioma: A case report of a diagnostic pitfall

RATIONALE: Primary splenic angiosarcoma (PSAn) is a rare and aggressive vascular malignancy that poses diagnostic challenges because of its overlapping morphological and immunohistochemical features with benign splenic vascular tumors. PATIENT CONCERNS: A 71-year-old woman presented with left upper abdominal pain, severe anemia, thrombocytopenia, and a splenic lesion. Splenectomy and excision of a separate 1-cm hepatic nodule were performed, with initial pathological diagnoses of splenic littoral cell angioma and hepatic cavernous hemangioma. Persistent postoperative fever, progressive cytopenias, jaundice, hepatic dysfunction, and newly developed diffuse multifocal hepatic lesions subsequently occurred. DIAGNOSES: Pathological reevaluation of the splenic specimen using an expanded immunohistochemical panel resulted in a revised diagnosis of PSAn. The subsequently developed diffuse hepatic lesions were considered highly suspicious for hepatic metastases based on the radiological and clinical findings, although histological confirmation was unavailable. INTERVENTIONS: The patient underwent splenectomy and excision of the initial hepatic nodule. Multidisciplinary reassessment and pathological reevaluation were performed following clinical deterioration. The patient declined liver biopsy and further oncological treatment. OUTCOMES: Despite supportive management, the patient's condition progressively deteriorated. She was discharged after 2 weeks and died 2 months later. LESSONS: PSAn should be considered in the differential diagnosis of splenic vascular tumors, particularly when morphological and immunohistochemical findings overlap. Unexpected postoperative deterioration should prompt timely multidisciplinary reassessment and pathological review.