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.

Schwannomatosis is a recently recognized distinct form of neurofibromatosis (NF). It is a rare condition, the incidence of which varies between 1/400,000 and 1/1.7 million. An important feature of schwannomatosis is the presence of multiple intracranial, spinal, and peripheral schwannomas in the absence of acoustic neuromas. Schwannomatosis presenting with intraosseous schwannoma of the mandible is even rarer, and only a few cases have been reported. It usually affects individuals in the third to fifth decade of life. Usually, it is sporadic in origin, but in 20% of patients, it can be familial. As a diagnostic criterion, NF2 gene is not involved in schwannomatosis. We report a case of a 48-year-old male presenting with facial pain and difficulty in chewing, and subsequent development of spastic paraplegia. Magnetic resonance imaging scan of head and neck revealed mass lesion involving infratemporal region on the left side, intraosseous lesion of the mandible, and multiple mass lesions in the neck. Acoustic nerves were not involved. Mutagen-induced chromosome sensitivity analysis test suggested no predisposition for malignancy. His clinical features are suggestive of schwannomatosis, which is a recently recognized distinct form of NF.

The authors report the case of a spinal intradural schwannoma presenting with intracranial subarachnoid hemorrhage (SAH). Cerebral angiography did not show any intracranial lesion; however, MRI revealed two separate tumors in the lower segment of the spinal cord. The proximal lesion arising from the conus medullaris was well circumscribed and homogeneously enhanced, whereas the tumor in the cauda equina revealed hemorrhagic signals on MRI. This case also illustrates an unusual presentation of intracranial SAH simultaneously with intratumoral hemorrhage in a spinal cord schwannoma. The absence of hemorrhagic changes in the lesion arising proximal to the cauda equina region supports the mechanical theory proposed for the pathogenesis of hemorrhagic complications in spinal cord tumors.