Synchronous quadruple primary neoplasms: Glioblastoma, neuroendocrine tumor, schwannoma and sessile serrated adenoma in a patient with history of prostate cancer

Quadruple synchronous primary neoplasms are exceedingly rare with only one case reported in the English literature. We herein report a case of synchronous quadruple primary neoplasms in a 70-year-old Arabic male with a history of prostate cancer who presented to our hospital for work-up of a brain mass found at an outside hospital. Subsequent ¹⁸Fluorodeoxyglucose (FDG) positron emission tomography demonstrated a 5.9-cm temporoparietal mass and three additional lesions, each with increased maximum standardized uptake value (SUV_max). Histologic exami nation, immunohistochemistry and cytogenetic analyses of the lesional tissue revealed four primary neoplastic lesions: primary glioblastoma, inguinal schwannoma, well-differentiated neuroendocrine tumor of the terminal ileum and an appendiceal sessile serrated adenoma/polyp. This case is unique among previous reports as our patient presented with four primary neoplasms synchronously. To the best of our knowledge, this combination of synchronous multiple primary neoplasms has not been reported in the English literature.