Congenital insensitivity to pain with anhidrosis: morphological and morphometrical studies on the skin and peripheral nerves.

A rare case of congenital insensitivity to pain with anhidrosis is presented. The male patient, who expired at 17 years of age, was noted insensitive to pain and bouts of unexplained fever at birth. He frequently fractured the hands and feet with secondary osteomyelitis. He did not sweat even in warm season. The intradermal nerve fibres and sweat glands were normal in distribution. The peripheral nerve seemed to be almost normal with light microscopy but the electron microscopical study revealed extreme paucity of unmyelinated fibers and a reduction of myelinated fibres, especially of small caliber. Abundant collagen fibrils comprised the endoneurium. There were no regenerative and/or degenerative changes of axons and myelin sheaths. The pathology of the peripheral nerve was considered to be congenital. Our case might belong to a category of congenital sensory neuropathy with anhidrosis (Pinsky and Di George 1966), congenital insensitivity to pain with anhidrosis (Gillespie and Perucca 1960) or hereditary sensory neuropathy type IV (Dyck and Ohta 1975, Goebel et al 1980).