MYCOSIS-FUNGOIDES METASTASIZING TO THE BRAIN PARENCHYMA - CASE-REPORT

OBJECTIVE AND IMPORTANCE: Mycosis fungoides is a rare T-cell lymphoma of the skin that can, in one-half to three-quarters of patients suffer ing from this disease, involve the viscera in late stages of the disea se. Although autopsy series performed more than 2 decades ago showed t hat the incidence of metastatic mycosis fungoides to the central nervo us system is approximately one of seven, a total of only several dozen cases have been reported to date. As compared to meningeal involvemen t, intraparenchymal metastases are even rarer. We describe a biopsy-pr oven case of intraparenchymal central nervous system mycosis fungoides in a patient with nonprogressive skin involvement and no detectable v isceral involvement, and we present a review of the relevant literatur e. CLINICAL PRESENTATION: A 68-year-old man, 3 years after the diagnos is of his skin disease, developed fatigue, confusion, and frontal lobe signs without the presence of cerebriform cells in the peripheral blo od or any other clinical evidence of visceral involvement. Magnetic re sonance imaging revealed a diffuse area of increased T2-weighted signa l involving the white matter of both cerebral hemispheres as well as a focal area of T2 abnormality along the body of the corpus callosum. T he radiological differential diagnosis was either leukodystrophy cause d by chemotherapy, progressive multifocal leukoencephalopathy, or glio ma with associated white matter changes. INTERVENTION: A stereotactic serial brain biopsy revealed diffuse perivascular infiltrates of atypi cal lymphocytes, as well as several large cells with cerebriform nucle i consistent with mycosis fungoides. The cells were immunoreactive for LCA, MT1, UCHL1, and CD3. CONCLUSION: We stress the importance of inc luding mycosis fungoides as part of the differential diagnosis for a b rain lesion in patients with cutaneous T-cell lymphoma, because treatm ents do exist, and we conclude that a serial stereotactic biopsy may b e necessary to provide a definitive diagnosis.