[HTLV-I associated myelopathy (HAM) complicated with chronic polymyositis]

The patient was a 49-year-old woman. Since her age of 42, she noticed a proximal weakness of both legs. She also experienced pedal paresthesia and urinary frequency. Physical examination disclosed a diffuse goiter and bilateral Babinski sign. Results of EMG and muscle pathology were compatible with the diagnosis of polymyositis. Treatment with prednisolone improved muscle weakness, urinary difficulties and struma. 7 years later, HTLV-I antibody happened to be strongly positive both in serum and CSF. Then most of her neurological problems were attributed to HAM. However, recent studies of re-biopsy muscle specimens disclosed scattered necrotic fibers, phagocytosis and endomysial or perivascular infiltration of inflammatory cells. These infiltrating cells were classed mostly as helper/inducer T cells. These observations suggested the coexistence of polymyositis in the present case as well. So far, the combination of HAM and polymyositis has not been reported. It seems important to decide if HTLV-I could induce chronic polymyositis as in the case of HIV infections.