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

Abstract

Gastroblastoma is a rare gastric epitheliomesenchymal biphasic tumour composed of spindle and epithelial cells, reported by Miettinen et al in a series of three cases in 2009. All those cases arose in stomachs of young adults. Neither the epithelial nor the mesenchymal component displayed sufficient atypia to diagnose a carcinosarcoma or other malignancy. On immunohistochemistry, the epithelial component expressed cytokeratin, and the mesenchymal component was positive for vimentin and CD10. Miettinen et al designated these neoplasms as gastroblastomas based on their similarities with other childhood blastomas such as pleuropulmonary blastoma and nephroblastoma. This report describes a probable fourth case of this unique type of neoplasm. The present case arose in the gastric antrum of a 9-year-old boy. While similarities were evident with the other cases, there were some differences. The epithelial component was more predominant and showed more mature morphology. Immunohistochemically, the epithelial component showed immunolabelling for c-KIT and CD56. The mesenchymal component was only focally positive for CD10. Ultrastructually, desmosomes and microvilli were found supporting a truly epithelial lesion.

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

“…In ultrastructural studies, the epithelial cells had desmosomes and microvilli. 2 The case we present shares with the previously reported cases a similar immunomorphology, invasive architecture, yet overall bland cytology, and young patient age. This case is different because of the histologically proven nodal metastasis and the clinical findings of peritoneal spread.…”

“…It has been proposed that gastroblastoma may relate better to the spindle epithelial tumor with thymuslike differentiation and the desmoplastic nested spindle cell tumor of liver rather than blastomas. 2 These other tumors have demonstrated indolent behavior and excellent prognoses comparable to the previously reported cases of gastroblastoma. [4][5][6] In any event, gastroblastoma is a rare tumor, and optimal therapeutic strategies are unknown.…”

“…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.…”

AIRP Best Cases in Radiologic-Pathologic Correlation: Gastroblastoma: A Rare Biphasic Gastric Tumor

“…One was centered in the gastric wall, whereas the other manifested as a partially exophytic mass (2,3). To the best of our knowledge, imaging findings of the remaining three tumors were not described, even though one was seen as an exophytic mass on the greater curvature of the stomach at gross pathologic analysis (1).…”

“…Gastroblastoma should be included in the differential diagnosis along with other biphasic gastric tumors such as biphasic synovial sarcoma, teratoma, and carcinosarcoma (1,2). Its characteristic histologic features include demarcation between epithelial and mesenchymal components; mild atypia; a low mitotic index; and variable immunohistochemical staining with CD56 and CD10, a finding that helps confirm the diagnosis (1,2).…”