Some Renal Masses Did Not "Read the Book": A Case of a High Grade Hybrid Renal Tumor Masquerading as a Renal Cyst on Non-contrast Imaging.

Hybrid renal tumors (HRT) are rare neoplasms that contain both benign and malignant components. Sporadic solitary HRT that contain high-grade malignant pathology appear to be extremely rare [1]. We describe a case at our institution of a tumor that was characterized as a type-2 papillary RCC and atypical oncocytoma hybrid that mimicked a simple cyst on non-contrast computed tomography.

Malignant nerve sheath tumor of the spinal accessory nerve: a unique presentation of a rare tumor.

Background: Malignant peripheral nerve sheath tumors (MPNSTs), sarcomas originating from tissues of mesenchymal origin, are rare in patients without a history of neurofibromatosis.

Case Report: We report a case of an MPNST of the spinal accessory nerve, unassociated with neurofibromatosis, which metastasized to the brain. The tumor, originating in the intrasternomastoid segment of the spinal accessory nerve, was removed.