An unusual cause of low back pain: paravertebral muscle metastases of lung cancer.

Paravertebral muscle metastasis is an extremely rare cause of low back pain. Lipomas, haemangiomas, hibernomas and liposarcomas should be considered first in the aetiology of paravertebral muscle masses. Schwannoma, neurofibroma, ganglioneuroma and paraganglioneuromas that show contiguous spread should also be included in the differential diagnosis. Haematogenous metastases are most frequently caused by lung cancers. Lung cancers typically metastasize to liver, brain, bone, kidney, and adrenal glands. They rarely metastasize to skeletal muscles due to metabolism, high tissue pressure and blood flow of muscles. Our case was a 48-year-old male who had been smoking 40 cigarettes per day and presented to our clinic with low back pain and a mass in the lower back region. The mass in his lower back region was excised and histopathological examination confirmed metastasis of a neuroendocrine tumour. Further examinations revealed the lung as the primary source of the metastasis.