Melkersson Rosenthal syndrome: a histopathologic mystery and dermatologic challenge

Abstract

Melkersson Rosenthal syndrome (MRS) is rare disease of unknown etiology characterized by orofacial edema, facial nerve palsy and fissured tongue. Microscopically, it shows epithelioid non-caseous granulomas; however, edema and perivascular lymphocytic infiltrates have been described. Two different clinical forms of MRS are presented in this report. In the complete form (Case 1), the main histopathologic finding was a non-necrotizing granulomatous inflammation with 56% of the total number of cells composed of B cells (CD 20(+) ) principally located in the granuloma's center and 33% being T cells predominating in the surrounding area, of which 48% were CD 4(+) and 16% were CD 8(+) lymphocytes. In the monosymptomatic form (Case 2), the inflammatory cells were dispersed into the connective tissue without granulomatous formation. B cells were scanty, and 78% of the cells were CD 45(+) T cells, with 46% and 34%, CD 8(+) and CD 4(+) phenotype, respectively. These cases showed different clinical, histopathological and immunohistochemical forms of MRS, suggesting different host immune responses.