A Case of Extranodal Histiocytic Sarcoma of Stomach Mimicking Gastric Adenocarcinoma

Abstract

Histiocytic sarcoma is a rare malignant neoplasm that originates from a histiocytic hematopoietic lineage characterized by histiocytic differentiation and its corresponding immunophenotypic features. Patients with histiocytic sarcoma usually have a poor prognosis due to its aggressive clinical behavior. Here we report a rare case of extranodal histiocytic sarcoma of the stomach which was confirmed through immunohistochemical staining. A 71-year- old man was presented with epigastric pain. Gastroscopy, abdominal CT, and EUS revealed a mass located on the posterior wall of upper body and fundus of the stomach. Grossly, grayish white solid masses were seen extending down to the submucosal layer. Microscopically, the tumor cells had eosinophilic cytoplasm, abundant vacuole, and mitosis. Immunohistochemical staining revealed that the tumor cells were positive for LCA, CD68, and lysozyme. Early detection and accurate diagnosis of this rare neoplasm is important because it can make a great difference in prognostic outcomes. To make an accurate and definitive diagnosis, immunohistochemical staining is essential in the confirmation of histiocytic origin.

Primary Gastric Histiocytic Sarcoma Reminiscent of Inflammatory Pseudotumor: A Case Report with Review of the Literature

“…With regard to gastric histiocytic sarcomas, one previous case showed a relatively long survival (3 years) after surgery and adjuvant chemotherapy 5. On the other hand, a different case with small tumor size (2 cm) and no initial regional lymph node involvement developed multiple distant metastases before long, and this patient had not received chemotherapy 6. These examples suggest that adjuvant chemotherapy may be effective and prolong the survival of patients with gastric histiocytic sarcoma.…”

“…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 2,3,4,5,6. In all of these cases, the neoplastic cells were highly atypical, and malignancy was easily suggested based on the morphology.…”