Peripheral primitive neuroectodermal tumor of the stomach in a 14-year-old boy: a case report.

Although PNETs are rare malignancies, they should be considered in the differential diagnosis of submucosal gastric tumours in adolescents with clinical alarm symptoms.NET was confirmed by detection of the characteristic EWS/FLI-1 fusion gene, resulting in a reciprocal translocation t(11;22)(q24;q12). Three distinct liver metastases were detected by CT, MRI, and PET. The tumour failed to respond to neoadjuvant polychemotherapy with vincristine, etoposide, doxorubicin, and ifosfamide. Subtotal gastrectomy was performed and, surprisingly, we found diffuse metastatic infiltration of the liver that had not been detected by preoperative staging. Due to the diffuse metastatic disease the young patient's prognosis has to be considered very poor. Because of the tumour's intense expression of CD117 (c-kit), the patient is now treated with the tyrosine kinase inhibitor imatinib (STI571).