Regarding the algorithm for the diagnosis of early mycosis fungoides proposed by the International Society for Cutaneous Lymphomas: Suggestions from routine histopathology practice

Background: Routine clinicopathologic practice is expected to refine/validate the scoring system proposed in 2005 by the International Society for Cutaneous Lymphomas (ISCL) for the diagnosing early mycosis fungoides (eMF), classical type. Methods: An evaluation of 72 cases of erythematous and scaling dermatoses was employed with a partial implementation of the ISCL algorithm. Results: The selected cases fulfilled the clinical criteria proposed by the ISCL; routine histopathology allowed to reach the ISCL minimum score for a diagnosis of eMF in 45 cases. A clonal T-cell population was found in 4 out of 12 cases tested with the polymerase chain reaction, three of which with an already established clinicopathologic diagnosis of eMF. An aberrant immunophenotype was found in 11 cases, all of which already labeled as eMF on the basis of clinical and histopathologic features. 6 out of 27 patients with inconclusive clinicopathologic data underwent a new skin biopsy, which allowed to reach a diagnosis of eMF in two cases. Conclusions: The diagnosis of eMF still rests upon clinical features and conventional histology; a new skin biopsy is recommended for cases with no clear-cut diagnostic features.