Clinical characteristics of HTLV-1 associated dermato-polymyositis. Seven cases from Martinique.

Myositis linked to HTLV-1 is unfrequent. Over a period of 8 years, 14 patients with inflammatory myopathy were diagnosed in Martinique. Seven were seropositive for HTLV 1 antibody; the clinical and pathological data of whom are presented herein. Five patients presented with polymyositis, two with dermatomyositis. All seven patients had extra-muscular clinical features including neuropathy (4/7) and myelopathy (6/7), resulting in a quite peculiar clinical picture. Muscle biopsy showed a neurogenic process combined with myositic changes in 3/7 patients. Corticotherapy led to dramatic improvement in only one case, but with no sustained effect. HTLV 1 may be considered the etiological agent of this form of dermato-polymyositis, characterized by a clearly distinctive clinico-pathological picture, and a poor response to corticotherapy. As in the case of tropical spastic paraparesis/HTLV 1 associated myelopathy, careful assessment of non-steroidal therapy is now warranted.