Primary gastric epithelioid angiosarcoma: A case report of diagnostic biopsy pitfall.

Rationale: Angiosarcoma is an aggressive neoplasm derived from endothelial cells that may develop anywhere within the body. Here, we report a case of primary gastric epithelioid angiosarcoma initially misdiagnosed as poorly differentiated adenocarcinoma from the preoperative biopsy.

Patient Concerns: The patient was a 60-year-old male admitted to the hospital due to abdominal discomfort. The gastroscopy examination suggested advanced gastric cardia carcinoma. Subsequent biopsy pathology examination confirmed the diagnosis of poorly differentiated adenocarcinoma. Therefore, the patient underwent radical resection for proximal gastric cancer. Histopathology showed that the tumor cells were epithelioid with rich, eosinophilic cytoplasm. Immunohistochemical examination indicated that the tumor cells were CD34, CD31, and ERG.

Diagnoses: Based on clinical, morphological, and immunophenotypic evidence, primary gastric epithelioid angiosarcoma diagnosis was confirmed.

Interventions: The postoperative Tumor Node Metastasis staging was considered T4aN1Mx. The patient did not receive chemotherapy.

Outcomes: The patient died 3 months after the operation.

Lessons: Primary gastric epithelioid angiosarcoma is a rare gastric tumor. Given the epithelioid cell features displayed by tumor cells and the high expression of epithelial markers in tumor cells (83%), preoperative diagnosis is difficult and should be differentiated from adenocarcinoma or gastrointestinal stromal tumor.