A 73-year-old woman was hospitalized for right hemicrania. She reported a recent access of atrial fibrillation and a 3-year history of diffuse skin dryness and erythema. The results of computed tomography of the head were normal, and her headaches improved spontaneously. She was therefore referred to our department for evaluation of her skin condition. Clinical examination revealed an erythroderma with widespread lymphadenopathic disease. Histologic findings in skin and nodal biopsy specimens were those of an epidermotropic CTCL with node involvement. Peripheral blood analyses revealed moderate leukocytosis and lymphocytosis, with a Sézary cell count of 3400/μL, a CD4/CD8 ratio greater than 20, and less than 7% T cells that expressed CD7. The same clonal amplification of T cells was demonstrated by T-cell receptor gene analysis in skin, blood, and lymph nodes. The diagnosis of SS was established according to previously published criteria from the International Society for Cutaneous Lymphomas.3 The patient informed physicians that she was experiencing gradual weakness, which affected several regions, including the right facial nerve which had a typical Bell palsy (Figure 1), the left third cranial nerve, the right lower leg, and the right upper limb. She began to require the use of a wheelchair. A lymphomatous leptomeningeal involvement was ruled out by normal or negative results of cerebral, spinal, and cranial magnetic resonance imaging; bone scintigraphy; and subsequent cerebrospinal fluid analyses. Human T-lymphotropic virus 1, human immunodeficiency virus, and Borrelia burgdorferi serologic test results were negative. The electromyogram showed a polyneuropathy with axonal radiculoneuropathy and low motor potential amplitudes, mostly affecting external and internal popliteal sciatic nerves. Three cycles of chemotherapy with cyclophosphamide, vincristine sulfate, doxorubicin hydrochloride, and prednisone (CHOP), associated with a methylprednisolone bolus, followed by oral prednisone (1 mg/kg/d) and chlorambucil improved cutaneous lesions and decreased the Sézary blood cell count, but the patient's motor condition worsened. A biopsy of the right superficial peroneal nerve and the adjacent muscle was performed. Histologic examination showed a neurogenic muscular atrophy and a decreased number of myelinated fibers with major wallerian degeneration. The wall of an epineurial artery and the endoneurium were infiltrated by large atypical cells with mitoses and convoluted nuclei (Figure 2). The diagnosis of axonal neuropathy secondary to a neural infiltration by Sézary cells was established.