Gastroblastoma With MALAT1::GLI1 Fusion Gene in an 18-Year-Old Man: A Case Report and Literature Review.

ObjectiveGastroblastoma is a rare biphasic neoplasm. This study aims to explore its clinicopathological features, immunophenotype, and molecular genetic alterations to enhance understanding and prevent misdiagnosis.MethodsWe retrospectively analyzed an 18-year-old man with gastroblastoma, and relevant literature was reviewed and summarized.ResultsHistologically, the tumor exhibited a distinctive biphasic pattern. The majority of tumor cells were epithelioid, arranged in nests, cords, glands, and rosette-like structures, with eosinophilic secretions within lumina. Focally, spindle-shaped tumor cells were observed. Mitotic figures were rare. Immunohistochemically, epithelioid cells expressed AE1/AE3, CD56 (NCAM1), and partially expressed CD10 (MME). Spindle cells expressed CD10, and CD56. Next-generation sequencing revealed a MALAT1::GLI1 fusion gene. No recurrence or metastasis was observed during a 17-month postoperative follow-up.ConclusionGastroblastoma is a rare entity that poses diagnostic challenges. Accurate diagnosis relies on integrating histomorphological features with immunohistochemical studies and molecular analysis. Surgical resection is the treatment of choice.