Solitary spinous process metastasis: a case report.

Vertebral column is a common site for bony metastases in patients with systemic malignancy. Patients with metastatic spinal tumors usually present with pain. Some tumors are asymptomatic and can be detected during screening examinations. Magnetic resonance imaging (MRI) of the vertebral column with the panel of available imagining methods and the clinical findings should be used for the diagnosis of spinal metastasis. A 45-year-old man was admitted with low back pain. With a history of rectum surgery and radiotherapy, he was on chemotherapy for rectum adenocarcinoma. F18 sodium fluoride positron emission tomography scan which was performed three weeks ago showed no abnormalities other than the primary surgical site. Magnetic resonance imaging of the lumbar vertebrae spine revealed a lesion on the tip of L4 spinous process. Excisional biopsy of L4 spinous process was performed. Histologic examination revealed mucinous adenocarcinoma. He had no low back pain at two-months follow-up. We could not find any solitary spinous process metastasis reported in English literature. Patients with nonspecific spinal pain with a previous cancer history should be carefully evaluated for a spinal metastasis. Even a solitary spinous process lesion may turn out to be the initial manifestation of a spinal metastasis.