[Mononeuropathy in chronic lymphatic leukaemia]

Chronic lymphatic leukaemia (CLL) is the most frequent form of leukaemia in the adult population in western countries. Only 7.2% of the complications of CLL are neurological and most of them are secondary to an infection by herpes zoster virus.

We report the case of a 71-year-old female with B-type CLL in stage IV or type C that was progressing and becoming diffuse large B-cell lymphoma (Richter's syndrome), who developed an incomplete axonotmesis of the left peroneal nerve and numerous violet-coloured nodules under the skin in the left knee. Magnetic resonance imaging showed signs of diffuse infiltration into the subcutaneous tissue and the muscles of the left leg; a biopsy study of one of the subcutaneous nodules revealed a lymphoid infiltration by large B-cells. In this patient, the injury to the left peroneal nerve was probably secondary to a lymphoid infiltration of the nerve from adjacent infiltrated soft tissues.

Peripheral neuropathy due to direct infiltration can be a neurological complication of CLL that has not be reported to date, but which is known to occur in other lymphoproliferative processes.