Malignant triton tumor: Grand Round presentation of a rare aggressive case thoracolumbar spine tumor.

INTRODUCTION: We report a rare and aggressive case of malignant triton tumor (MTT) at the thoracolumbar junction with foraminal extension mistreated as schwannoma. MATERIALS AND METHODS: A 70-year-old man with a 2-year history of lower back pain and left L4 radiculopathy with no history of neurofibromatosis. RESULTS: Pre-operative MRI suggested a typical schwannoma. Upon complete marginal resection, histological findings revealed a MTT. The patient presented with a local and regional recurrence and died 10 months after surgery. MTTs are a subgroup of malignant peripheral nerve sheath tumors, which develop from Schwann cells of peripheral nerves or within existing neurofibromas, and display rhabdomyoblastic differentiation. CONCLUSION: Based on the Grand Round case and relevant literature, we present a case of a highly aggressive and fast-growing tumor with a very high local and distant recurrence. There is no consensus treatment plan available and patients usually die shortly after diagnosis.

Paraspinal hibernoma: Grand Round presentation of a rare benign adipocytic tumor.

INTRODUCTION: We report an uncommon case of paraspinal hibernoma with a T12-L1 foraminal extension and discuss the potential differential diagnoses of paraspinal adipocytic tumors. MATERIALS AND METHODS: A 32-year-old woman consulted our department with a right subscapular and paraspinal mass. There was no associated neurological deficit. The MRI revealed a paraspinal adipocytic tumor with a T12-L1 right foraminal extension. Percutaneous biopsy suggested a diagnosis of hibernoma. RESULTS: Hibernoma is a rare and benign adipocytic tumor arising from embryologic remnants of brown fat. Specific MRI findings are discussed to differentiate hibernoma from other soft-tissue tumors. A planned marginal resection was undertaken with the final histopathology confirming the diagnosis of hibernoma. CONCLUSION: Based on the Grand Round case and relevant literature, we discuss a rare case of paraspinal hibernoma with a foraminal component and no recurrence at 3-year follow-up.