Dumbbell-type Spinal Solitary Fibrous Tumor With Paraplegia

: Solitary fibrous tumors are rare tumors that most commonly arise in the pleura. This article describes a case of a large dumbbell-shaped solitary fibrous tumor of the thoracic spine that was causing partial paraplegia. The patient was a 75-year-old woman who presented with swelling of the upper back and weakness of the lower extremities. Magnetic resonance imaging revealed a dumbbell-shaped tumor mass compressing the spinal cord, predominantly at the level of T8. The tumor extended transversely from the bilateral foramen of T8-T10 to the back muscles. The patient experienced increasing weakness of the lower extremities, so a T7-T11 laminectomy was performed and the tumor was excised piecemeal. Microscopically, the tumor was found to be composed of a proliferation of fibroblastic spindle cells. Immunohistochemically, it was strongly positive for CD34 but negative for S100. These findings were consistent with a solitary fibrous tumor. Three months postoperatively, thoracic radiographs showed progression of spinal kyphosis. Posterior fusion with instrumentation was performed. Three years postoperatively, there was no clinical evidence of tumor recurrence. Spinal solitary fibrous tumors are rare, particularly dumbbell-shaped tumors; to our knowledge, only 2 have been reported in the literature. The correct diagnosis is aided by noting the bland fibrous histology, strong CD34 immunostaining, and absence of S100 and cytokeratin positivity. Although solitary fibrous tumors of the spine are rare, they should be considered in the differential diagnosis of intraspinal lesions, particularly those occurring near pleura.