Central nervous system involvement in mycosis fungoides: relevance of tcr gene testing in cerebrospinal fluid

INTRODUCTION: Mycosis Fungoides (MF) is a rare malignant T-cell lymphoma, involving mainly the skin. In 50%–75% of cases, it can involve organs other than skin, with a 11%–14% Central Nervous System involvement (CNS). CASE REPORT: A 82-year-old woman presented to our Department with a 15-years history of MF with skin lesions. Neurological examination showed dysarthria and a left facio-brachial-crural hemiparesis. A CT scan showed a right fronto-rolandic lesion. A MRI, including DWI, confirmed the presence of the “neoplastic” lesion with slight hemorrhagic component and leptomeningeal contrast enhancement. Molecular TCR rearrangement test by PCR analysis was performed on skin biopsy, showed the presence of a single peak which fits with a monoclonal TCRG gene rearrangement (size 67). Molecular TCR test was also performed on the cerebrospinal fluid (CSF), which confirmed the presence of lymphocyte clone T g/ more expressed with the same size of that observed in the skin biopsy A total body CT scan did not show any lymphnodal or extranodal disease. The patient died after ten days. CONCLUSION: MF usually occurs in the context of advanced and often histologically transformed cutaneous disease. Isolated CNS involvement is remarkably rare. This case highlights the need for regular neurologic follow-up after the diagnosis of MF, in particular when features that suggest risk of disease progression are present. Furthermore, the analysis of the skin biopsy and above all of CSF by PCR technique, based on our experience, should always be executed in MF patients with signs or symptoms suggesting CNS involvement.