An incidental discovery of a gastric follicular dendritic cell sarcoma: A rare case report and a literature review.

Follicular dendritic cell sarcomas (FDCS) are rare tumours, typically seen in lymph nodes. However, in about one third of the reported cases, a FDCS presents as an extranodal mass. Involvement of the gastrointestinal tract is rare, and the stomach is even rarer with only four cases described to date. The aim of this study was to review clinical characteristics, pathologic features, emphasize on differential diagnosis and discuss therapeutic modalities and prognosis of this rare entity. We report on a 36-year-old female patient with no past medical history, an incidentally discovered FDCS located in the stomach with the presence of lymph node metastasis at the time of diagnosis. The diagnosis of a FDCS was made on morphological and immunohistochemical findings where tumor cells expressed CD21 and CD23. The tumor was resected by gastrectomy with extended para-aortic lymphadenectomy, with uneventful postoperative course. Due to its rarity, FDCS is rarely included in the differential diagnosis of gastrointestinal spindle cell tumors. Complete surgical resection is the current gold standard of treatment.