Multifocal gastrointestinal stromal tumor with osseous metaplasia: a case report.

BACKGROUND: Gastrointestinal stromal tumor is considered the most common mesenchymal neoplasm of the gastrointestinal tract. The majority of gastrointestinal stromal tumor cases are located in the stomach and usually affects older adults. Most of gastrointestinal stromal tumor cases are sporadic; however, few have a syndromic association, including Carney triad, Carney-Stratakis syndrome, familial gastrointestinal stromal tumor syndrome, and neurofibromatosis type 1. CASE PRESENTATION: Herein, we report a rare case of a 54-year-old Middle-Eastern female with multifocal gastrointestinal stromal tumor mixed type (epithelioid and spindle cell type) with osseous metaplasia. Fluoresce in situ hybridization analysis of platelet-derived growth factor receptor alpha revealed deletion in 42% of the tumor cells studied. Interestingly, next generation sequencing revealed platelet-derived growth factor receptor alpha exon 12 mutation (p.Y555C) and exon 14 mutation (p.N659Y). CONCLUSIONS: In conclusion, osseous metaplasia in GIST is a very rare event and only few cases are reported in the literature. The number of reported cases is inadequate to confirm the pathogenesis and the prognosis.

A 37-Year-Old Saudi Man with a Calcified Intraventricular Astrocytoma.

BACKGROUND Pilocytic astrocytoma is a low-grade glioma that is common in children. Pilocytic astrocytoma is a slow-growing neoplasm that may calcify and occurs throughout the central nervous system, but it has a preference to be located infratentorial in children. CASE REPORT Herein, we report an unusual intraventricular location of pilocytic astrocytoma with extensive calcification in a 37-year-old Saudi man who mainly presented with a headache. Although pilocytic astrocytoma can arise throughout the central nervous system, it very rarely arises from the ventricles, especially the lateral ventricle. CONCLUSIONS The majority of intraventricular tumors arise within the third and fourth ventricles. The unusual intraventricular location and the unexpected age group are the main difficulties in diagnosing an adult with intraventricular pilocytic astrocytoma. Intraventricular pilocytic astrocytoma can be missed radiologically and misled pathologically; therefore, it should be considered within the differential diagnosis of intraventricular tumors. To the best of our knowledge, this is the first case to be reported in Saudi Arabia.