Extradural Dumbbell-Shaped Tuberculoma Masquerading as Nerve Sheath Tumor: Case Report and Review of Literature.

Abstract

Spinal tuberculosis has been listed as a rare cause of neuroforaminal widening with only 2 previous reports in the literature. Here, we report the third case of an extradural tuberculoma extending through and expanding the neural foramen closely masquerading as a nerve sheath tumor including, to the best of our knowledge, the first description of magnetic resonance imaging, operative, and histopathology findings. A 65-year-old Nigerian man presented with signs and symptoms of worsening thoracic myeloradiculopathy for the past month. Imaging found an extradural dumbbell-shaped lesion involving the spinal canal, neural foramen, and paraspinal area with a combination of solid and cystic components causing bony remodeling of the pedicle and vertebral body, as well as enlargement of the neural foramen. Surgery was performed to resect the mass, and pathology postoperatively demonstrated caseating granulomas, rare thin elongated organisms on Ziehl-Neelsen staining, and involvement of nerve fascicles. This case illustrates that a tuberculoma can have many of the features of a benign neoplasm, such as encapsulation, appearance of a slow rate of growth, and development of necrosis or even cystic degeneration. With the specific findings of entrapped nerve fascicles, we postulate that the lesion represents a nerve sheath tuberculoma rather than spinal tuberculosis of the pedicle or posterior elements. Furthermore, only a lesion of the nerve sheath would have the characteristic dumbbell appearance as it extends through the foramen.