Meningeal involvement by a transformed mycosis fungoides following Hodgkin's disease

A 58-year-old man had long-standing lesions of presumed large plaque paraps oriasis. Following treatment for nodal Hodgkin's disease (KD), these became more infiltrated, with a diagnosis of mycosis fungoides (MF). A few months later, nodules appeared on the right leg, which was lymphoedematous after inguinal irradiation for HD. Histopathological examination showed CD3+, CD3 0-, CD15- large preomorphic lymphocytes, leading to the diagnosis of transf ormed MF. The cutaneous lesions were successfully treated with topical nitr ogen mustard and interferon alfa-ab then methotrexate, but his general heal th worsened with depression and malaise, without specific neurological symp toms or extracutaneous spreading of the lymphoma. Cerebral computed tomogra phic scan revealed a cerebellar subdural collection, arachnoid cyst and qua driventricular hydrocephaly, initially considered to be non-specific. After a few weeks, clinical symptoms of intracranial hypertension appeared, and a cerebrospinal fluid (CSF) examination revealed meningeal involvement by t he lymphoma. These cells were CD3-negative and the diagnosis was confirmed by polymerase chain reaction (PCR) study, which revealed an identical clona l rearrangement of the T-cell receptor gamma gene between cutaneous biopsie s and the CSF. Repeated intrathecal injections of methotrexate and cranial irradiation were performed and the patient was still alive after 13 months. This case illustrates the possible meningeal involvement of MF that may be preceded by atypical and mild neurological or psychiatric symptoms, which may be dissociated from the evolution of the cutaneous lesions. Moreover, P CR study may be useful for both diagnosis and monitoring.