190 Multifocal Histiocytic Sarcoma of the Stomach. (11th January 2018)

• Record Type: Journal Article
• Authors: Mahabir, Roshan; Singh, Kunwar; Levi, Gabriel
• Is Part Of: American journal of clinical pathology. Volume 149(2018)Supplement 1
• Page Start: S81
• Page End: S81
• Publication Date: 2018-01-11
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqx121.189
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: Histiocytic sarcoma (HS) is a rare malignant proliferation of mature histiocytic cells accounting for less than 1% of all lympho-hematologic malignancies with a median age of 55 years at presentation and poor prognosis. HS generally presents in the lymph nodes, but the gastrointestinal tract is the most common extra-nodal site. Physical findings usually include lymphadenopathy, splenomegaly, hepatosplenomegaly or skin lesions and usually presents as a solitary mass. Here we present a case of a 76-year-old woman with past medical history significant for coronary artery disease who was admitted for symptomatic upper gastrointestinal bleeding. Endoscopy revealed multiple gastric polyps, and the patient subsequently underwent total gastrectomy for persistent bleeding. On gross examination, there were multiple, pedunculated polyps as well as an underlying thickened wall predominantly located in the fundus with sparing of the lesser curvature. Sectioning of the masses revealed uniform, fleshy cut surfaces with intact muscularis propria. Histological examination of the specimen showed mixed epithelioid and spindled cell morphology with increased mitotic rate and necrosis. Cytologically, the nuclei were uniformly enlarged with pale eosinophilic cytoplasm and prominent nucleolus. On immunohistochemistry, the tumor cells showed strong reactivity with histiocytic antigens PU.1/ CD163 and weakly reactive for CD68. In addition, vimentin was positive, but markers of epithelial, muscular, neural, lymphocytic, and melanocytic origin were all negative. Ki-67 showed a proliferative index of 30%. Follow-up of the patient shows persistent bleeding with local recurrence at the surgical site and metastasis to the left atrium. This case represents an unusual lesion in the differential diagnosis of gastric epithelioid and spindled neoplasms. Due to its aggressive nature, early recognition of this entity is required for appropriate management.