Adrenal schwannoma can be FDG-Avid on PET/CT: case report and review of historic institutional pathology

Abstract

Schwannomas are benign, generally indolent tumors of neural crest origin and comprise the most common histologic tumor of peripheral nerves. Schwannomas are a rare histology for retroperitoneal tumors and very rare histologic findings for tumors of the adrenal gland with fewer than 50 cases in the reported literature. Here we present a case report of a non-hormonally functional but metabolically active adrenal tumor with indeterminate imaging characteristics with final pathology showing a 6.1 cm adrenal schwannoma as well as historical institutional pathology review revealing two additional cases.

18F-FDG PET/CT revealed sporadic schwannomatosis involving the lumbar spinal canal and both lower limbs: a case report

“…It is mostly round or lobulated, well-defined, encapsulated, of moderate hardness or elasticity, without fluctuation, and when the larger tumor appears to have mucoid degeneration, a puncture can draw out non-coagulating bloody fluid ( 20 ). Microscopically, schwannomas show spindle-shaped tumor cells arranged in two phases: some cells are closely adjacent to nuclear palisade-like arrangements (with Verocay bodies in the Antoni A area), while other areas only see loose aggregation of cells on a mucoid background (Antoni B area) ( 21 , 22 ). The lesion often exhibits prominent thick-walled blood vessels, along with frequent occurrences of mucoid degeneration, hemorrhage, and calcification within the tumor.…”

“…Schwannoma is a tumor composed of mixed Schwann cells, perineurial-like cells, and fibroblasts, with scattered nerve fibers, linear collagen bands, and mucoid matrix (19). It is mostly round or in the Antoni A area), while other areas only see loose aggregation of cells on a mucoid background (Antoni B area) (21,22). The lesion often exhibits prominent thick-walled blood vessels, along with frequent occurrences of mucoid degeneration, hemorrhage, and calcification within the tumor.…”