Collision tumor between a spinal schwannoma and chronic lymphocytic leukemia/small lymphocytic lymphoma: case report and review of the literature.

A collision tumor is one where two neoplasms of differing type occur at the same anatomical site. We present a patient suffering from non Hodgkin small cell lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) and complaining intense lumbar back pain refractory to medical treatment. Lumbosacral MRI showed an intradural extramedullary lesion in the left L2-L3 foramen with extracanalar development and compression of psoas muscle. CT showed intralesional calcification. The patient underwent resection of the lesion through a paraspinal posterolateral approach (Wiltse approach). The histology was of schwannoma with intralesional calcifications and lymphocitic infiltrates compatible with B-lineage SLL/CLL. After the operation the patient suffer from left psoas muscle motor weakness (3/5 MRC). Because of hematological disease progression, she underwent 6 cycles of chemioterapy (Fludarabine, Cyclophosphamide, Rituximab). At a six-month follow-up no recurrence or residual tumor upon lumbosacral MR imaging was detectable and the left thigh flexion returned normal. To our knowledge, this is the first described case in the literature of collision tumor between a solitary spinal Schwannoma and SLL/CLL.