An Osteoclast-Rich Tumor of the Gastrointestinal Tract with Features Resembling Clear Cell Sarcoma of Soft Parts: Reports of 6 Casesof aGIST Simulator

Abstract

Six cases are reported of an osteoclast-rich tumor of the gastrointestinal tract that should be segregated from GIST. Five of the cases were located in the small bowel and one in the stomach. The age of the patients ranged from 13 to 37 years. The tumors behaved aggressively, with metastases to regional lymph nodes, liver, and other intra-abdominal sites. Microscopically, the tumor cells were medium-sized, predominantly oval, relatively monomorphic, diffusely immunoreactive for S-100-protein, and negative for CD117, CD34, HMB-45, and Mart-1. They were admixed with scattered osteoclast-like, multinucleated giant cells which were S-100-protein negative and KP1-positive. One case studied cytogenetically had the karyotype 46XX t(12;22)(q13;q12). The cases here reported are interpreted as examples of a distinctive type of gastrointestinal neoplasm which shares some features with clear cell sarcoma of soft parts (melanoma of soft parts), including in one case the chromosomal translocation that is characteristically associated with that entity.

EWS-CREB1: A Recurrent Variant Fusion in Clear Cell Sarcoma—Association with Gastrointestinal Location and Absence of Melanocytic Differentiation

“…Microscopically, the predominant pattern is of nested or solid growth of small epithelioid cells with amphophilic or clear cytoplasm and uniform nuclei with conspicuous nucleoli. However, certain cases contain somewhat distinctive morphologic features, due to a component of admixed reactive, KP1-positive, and osteoclast-type giant cells (9,23). One of our cases showed a similar, although very minor, component of osteoclast-type giant cells.…”

“…In spite of the negativity for melanocytic markers, the morphologic appearance coupled with the t(12;22) translocation supports a diagnosis of CCS in such cases. Although all three of our EWS-CREB1-positive CCS lacked melanocytic expression by immunohistochemistry, this was also noted in four of eight previously reported EWS-ATF1-positive CCS of the gastrointestinal tract (9,21,23,24), suggesting that gastrointestinal location rather than the fusion transcript type might determine the lack of melanocytic differentiation. Furthermore, two additional gastrointestinal CCS from our files (not previously reported, see Supplementary Table S1), showing either EWS-ATF1 by RT-PCR or EWS rearrangement by FISH lacked evidence of melanocytic differentiation by immunohistochemistry.…”

“…Gastrointestinal CCS includes a histologic variant rich in osteoclast-type giant cells which uniformly express S100 protein, but lack melanocytic differentiation by immunohistochemistry, being negative for HMB45 and Mart-1 (9). As a result of its rarity in the gastrointestinal tract, the differential diagnosis of CCS in this site includes more common mesenchymal or neuroectodermal neoplasms, such as gastrointestinal stromal tumors, schwannoma, carcinoid, or metastatic melanoma.…”

Gastrointestinal clear cell sarcoma-like tumour of the ascending colon

“…4,6 However, only 16 of these reports describe neoplasms that correlated with the accepted morphological, structural and immunohistochemical features of a 'true' CCSLGT. A CCSLGT has features very similar to those of a CCS but with no specific evidence of melanocytic differentiation.…”

“…[1][2][3][4] They are highly aggressive tumours that commonly reoccur with widespread metastatic nodal and visceral disease, even after treatment. 1 These tumours were originally thought to be related to clear cell sarcomas (CCSs) of tendons and aponeurosis.…”