Cryoglobulinemic neuropathy: ultrastructural study of the nerve capillaries.

The authors report here the case of a female patient who developed symmetrical polyneuropathy of the lower limbs a few months after she was found to have a myeloma with cryoglobulinemia. In musculocutaneous nerve biopsy material from this patient, electron microscopy showed pathological changes in the nervous tissue together with axonal degeneration and demyelination. But the most striking finding was the presence in the endoneurial space, of numerous masses made up of closely packed tubular structures. These masses occurred also in the walls and even in the lumen of all the vasa nervorum. Their morphologic features and dimensions were identical to cryoprecipitate which the authors extracted from the serum and which they examined with electron microscope.