[Neuropathy with contractures evoking the stiff-man syndrome. Latent solitary plasmacytoma].

A further case of apparently primary sensorimotor neuropathy is reported. The patient, a 31-year-old man, developed the syndrome after a 4-year history of a solitary vertebral plasmocytoma revealed by post mortem examination. Circulating monoclonal immunoglobulin and specific anomalies on nerve biopsy were absent. The condition became progressively worse, with initial and predominant autonomic nervous system anomalies. After 3 years, contractures of the limbs and paravertebral muscles, with painful paroxysmal attacks suggestive of the stiff-man syndrome appeared. Pathology confirmed the severity of the root lesions with diffusion to the cranial nerves. Reflex tests could not be conducted but the semiologic characteristics and the efficacity of baclofen were distinctive of continuous muscle fiber activities reported in some peripheral neuropathies. This case was comparable to some reported ones of interneuron rigidity.