Osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcoma of soft parts

Abstract

Clear cell sarcoma is a high-grade sarcoma with morphological features resembling those of malignant melanoma. An osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcomas of soft parts is very rare. Herein, we report an unusual stomach tumor with microscopic and immunohistochemical characteristics of an osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcomas of soft parts. The tumor cells were predominantly oval, admixed with some round and spindle elements arranged in nests and fascicles, and admixed with scattered osteoclast-like multinucleated giant cells. Neoplastic cells were positive for S-100 protein, and osteoclast-like multinucleated giant cells were immunoreactive to CD68. The unusual morphology of the tumor caused significant diagnostic difficulties. The differential diagnosis included gastrointestinal stromal tumor, primary or metastatic melanoma, and epithelioid malignant peripheral nerve sheath tumor. To the best of our knowledge, this is possibly the second description of an osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcomas of soft parts.

Clear Cell Sarcoma–like Tumor of the Gastrointestinal Tract: An Evolving Entity

“…Of 25 cases in the literature that involved assessment for the presence of at least one neuroendocrine marker (including chromogranin-A, synaptophysin, neuron-specific enolase, and CD56) immunohistochemically, 19 (76%) were shown to express at least one of these markers. 1,2,6,[8][9][10]13 In the series by Stockman et al, 13 all cases expressed SOX10 (further supporting evidence of a primitive neural phenotype for CCSLGT) and vimentin. Markers associated with gastrointestinal stromal tumor (GIST)-CD117, DOG1, CD34-are universally negative, and CCSLGT is also negative for desmin, smooth muscle actin, pancytokeratin AE1/AE3 (although 1 of 8 cases has shown focal patchy positivity for Cam5.2), and CD99.…”

“…S100 protein positivity has been seen in all 38 CCSLGTs where it was performed, whereas the melanocyte-specific markers were negative in all CCSLGTs studied. 1,2,[5][6][7][8][9][10][11][12][13][14] This is in contrast to conventional-type CCSs occurring in the gastrointestinal tract, most of which are positive for S100 protein as well as melanocyte-specific antigens. There is now increasing evidence that many CCSLGTs also express neuroendocrine markers ( Figure 9).…”

“…[1][2][3] Clear cell sarcoma-like tumor of the gastrointestinal tract was first described as a distinct entity in 2003 in a series of 6 cases by Zambrano et al 3 However, cases that may be morphologically similar to CCSLGT have been reported previously, including by Alpers and Beckstead, 4 who reported a ''malignant neuroendocrine tumor of the jejunum with osteoclast-like tumor giant cells'' in 1985. To our knowledge, only 38 cases have been published, 1,2,5-14 of which 9…”

“…Another feature distinguishing CCSLGT from CCS and melanomas affecting the gastrointestinal tract is the absence of melanin pigment in all cases reported. 1,2,8,13 The lack of melanin pigmentation does not preclude diagnosis of CCS or melanoma, because amelanotic variants of these can occur. However, 6 of 7 cases of conventional CCS of the gastrointestinal tract were found to contain melanin where there was an active search for pigmentation.…”

Angiomatoid Fibrous Histiocytoma: The Current Status of Pathology and Genetics

“…CCSLGT is a rare, aggressive neoplasm occurring predominantly within the wall of the small bowel, stomach, or large bowel, particularly in young adults. [60][61][62] It is composed of medium-sized, round, or ovoid cells with clear or eosinophilic cytoplasm, in sheets or less frequently papillary or alveolar distributions, with variable numbers of CD68-positive osteoclast-like giant cells. CCSLGT expresses S100 protein but not other melanocytic markers and often also variably expresses neuroendocrine markers.…”