Gastroblastoma: a case report and literature review

Gastroblastoma (GB) is an extremely rare biphasic malignant embryonal tumor of the stomach, primarily seen in children, with limited case reports in adults. Due to overlapping histological features with other gastric tumors, its definitive diagnosis and the establishment of standardized treatment strategies remain challenging.

This paper reports an 18-year-old adult male patient who presented with abdominal pain. Preoperative imaging studies revealed a 3.8 cm mass in the gastric antrum, with an initial diagnosis of Gastrointestinal Stromal Tumor (GIST). The patient underwent laparoscopic subtotal gastrectomy. Postoperative histopathological examination showed the tumor was composed of epithelioid and spindle cell mesenchymal components, exhibiting biphasic differentiation. Immunohistochemistry (IHC) results showed positivity for Pan-Cytokeratin (PCK), CD56, and Vimentin, with a low Ki-67 index (5%). A final diagnosis of GB (pT4aN2aM0) was confirmed. The patient did not receive adjuvant therapy postoperatively and showed no signs of tumor recurrence or metastasis at 14 months of follow-up.

The diagnosis in this case was established based on the characteristic histological morphology and immunohistochemical features. Although molecular testing has been shown to provide significant auxiliary value in previous studies, the patient did not undergo relevant testing due to personal preferences. Molecular studies indicate that abnormal activation of the Hedgehog/GLI signaling pathway is its core molecular pathological basis, often involving fusion genes such as MALAT1-GLI1. Radical surgical resection is the primary treatment modality, and the overall prognosis is favorable. Future efforts require strengthening multi-center collaboration, further investigating the molecular mechanisms, and developing individualized treatment strategies, including those targeting the Hedgehog pathway, to refine diagnostic and therapeutic guidelines and improve patient outcomes.