Usefulness of flow cytometry in the diagnosis of mycosis fungoides

BackgroundThe pathologic evaluation of mycosis fungoides (MF) is a challenging area in dermatopathology.ObjectiveWe sought to determine the usefulness of flow cytometry for the diagnosis of MF from skin biopsy specimens.MethodsSkin biopsy specimens from 22 patients with a clinical suggestion for MF were evaluated by 4-color flow cytometry. The results were correlated with the International Society for Cutaneous Lymphoma (ISCL) MF diagnostic score and molecular studies for T-cell receptor gene rearrangement.ResultsA T-cell abnormality by flow cytometry was identified in all 11 patients with diagnostic ISCL scores whereas the 7 patients with either subdiagnostic ISCL scores or reactive histology showed no phenotypic abnormality by flow cytometry. In all, 10 of 11 patients with diagnostic skin biopsy specimens for MF had T-cell receptor gene rearrangements by polymerase chain reaction. Gene rearrangements were not detected in the subdiagnostic group.LimitationsSmall study size was a limitation.ConclusionFlow cytometry of skin biopsy specimens is a sensitive method for detecting abnormalities in MF and should be considered part of the routine workup of patients with a clinical suggestion of MF.