Thymic plasmacytoma presenting as polyneuropathy and revealing multiple myeloma: a case report

Abstract Background Multiple myeloma (MM) is the most frequent malignant plasma cell disorder with proliferation of neoplastic cells in bone marrow or other tissue, commonly upper aerodigestive tract. The invasion thymus exceptional. Neurological complications are usual, but represent exceptionally revealing symptom. Case presentation We report a case polyneuropathy thymic plasmacytoma as mediastinal MM 48-year-old woman. She was admitted after developing progressive ascending distal paresthesias and weakness lower limbs. Examination showed symmetrical sensorimotor impairment axillary inguinal adenopathies. Electroneuromyography revealed length-dependent neuropathy. Serum protein electrophoresis monoclonal peak β-γ globulin region. Immunoelectrophoresis IgA lambda gammapathy. Myelogram biopsy plasmocytosis 5%. Chest computed tomography histologically confirmed associated lytic lesion 5th rib leading to diagnosis MM. Conclusions association between peripheral neuropathy rare workup for necessary guide therapeutic management.