A Distinctive Novel Epitheliomesenchymal Biphasic Tumor of the Stomach in Young Adults (“Gastroblastoma”)

Abstract

This report describes 3 cases of a distinctive, hitherto unreported gastric epitheliomesenchymal biphasic tumor that differs from other biphasic tumors of the stomach and elsewhere: carcinosarcoma, biphasic synovial sarcoma, teratoma, and mixed tumor. The tumors occurred in young adults, 2 males and 1 female, of ages 19, 27, and 30 years. Two tumors were located in the greater curvature in the gastric body and one in the antrum. The tumors measured 5, 6, and 15 cm in maximum diameter, and their mitotic rates were 0, 4, and 30 mitoses per 50HPF. There were 2 components: uniform oval or spindled cells in diffuse sheets, and clusters or cords of epithelial cells occasionally forming glandular structures with small lumens. The epithelial elements were positive for keratin cocktail AE1/AE3, keratin 18, and partly for keratin 7, but were negative for keratins 5/6, 20 and epithelial membrane antigen. The spindle cells were positive for vimentin and CD10. All components were negative for CD34, CD99, estrogen receptor, KIT, smooth muscle actin, desmin S100 protein, p63, calretinin, chromogranin, synaptophysin, CDX2, and thyroid transcription factor 1. In situ hybridization for SS18 rearrangement was negative in all cases separating this tumor from synovial sarcoma. All 3 patients were alive after follow-up of 3.5, 5, and 14 years. Because these tumors have some resemblance to blastomas of other organs, we propose the term "gastroblastoma" for this distinctive, at least low-grade malignant epitheliomesenchymal tumor of the stomach.

Novel epitheliomesenchymal biphasic stomach tumour (gastroblastoma) in a 9-year-old: morphological, usltrastructural and immunohistochemical findings

“…Gastroblastoma is a recently identified novel stomach epitheliomesenchymal biphasic tumour composed of uniform spindle and epithelial cells, reported by Miettinen et al in a series of three cases 1. Herein, we report a probable fourth case arising in the distal antrum of the stomach in a 9-year-old boy.…”

Gastroblastoma in a 28-Year-Old Man With Nodal Metastasis: Proof of the Malignant Potential

“…The 2 growth patterns did share some staining characteristics, although variably, with CD56 and CD10. A complete listing of immunohistochemical staining patterns is displayed in the Table. Other ancillary studies performed included fluorescence in situ hybridization for SS18 gene rearrangement 1 and c-KIT mutation analysis, 2 and the findings were negative. In ultrastructural studies, the epithelial cells had desmosomes and microvilli.…”

“…It has only been reported in 4 patients to date. 1,2 It has been likened to carcinosarcoma of the stomach, although it does not share the high-grade cytology or the dismal prognosis of carcinosarcoma. 3 When considering other multilineage tumors, such as synovial sarcoma, mesothelioma, teratoma, and blastomas, gastroblastoma is a distinct, rare entity of the stomach.…”

Inhibin-α and synaptophysin immunoreactivity in synovial sarcoma with granular cell features

“…gastroblastoma [27], and certain types of sex cord-stromal tumors. Biphasic malignant mesotheliomas consist of epithelial and sarcomatous components, but they usually blend with one another, and transitional areas may be seen.…”

“…Gastroblastomas, as recently reported by Miettinen et al[27], are rare gastric epitheliomesenchymal biphasic tumors that occur in young adults. Granular SS, which tends to occur in older patients, has a sharp demarcation between spindle cell component and granular cells.…”