Primary gastric histiocytic sarcoma reminiscent of inflammatory pseudotumor: a case report with review of the literature.

Histiocytic sarcoma is a malignant proliferation of cells showing similar morphologic and immunophenotypic features to mature tissue histiocytes. 1 It is a very rare neoplasm, and only a limited number of cases have been reported. Although it occurs in lymph nodes, the majority of cases present in extranodal sites, most commonly the intestinal tract, skin, and soft tissues. 2 In the intestinal tract, primary gastric involvement is exceptional; only a handful of cases have been reported in the English literature. 2-6 In all of these cases, the neoplastic cells were highly atypical, and malignancy was easily suggested based on the morphology. In the case presented here, diagnosis was a challenge due to the lack of a high degree of atypia or pleomorphism of the tumor cells. Herein, we report a case of primary gastric histiocytic sarcoma masquerading as an inflam matory pseudotumor. We also present the clinical characteristics of previously reported gastric histiocytic sarcomas by literature review.