J Cutan Pathol 2008: 35: 549–553 doi: 10.1111/j.1600-0560.2007.00858.x Blackwell Munksgaard. Printed in Singapore Copyright # Blackwell Munksgaard 2007 Journal of Cutaneous Pathology Continuing Medical Education Article 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. Ferrara G, Di Blasi A, Zalaudek I, Argenziano G, Cerroni L. Regarding the algorithm for the diagnosis of early mycosis fungoides proposed by the International Society for Cutaneous Lymphomas: suggestions from routine histopathology practice. J Cutan Pathol 2008; 35: 549–553. # Blackwell Munksgaard 2007. Gerardo Ferrara 1 , Arturo Di Blasi 1 , Iris Zalaudek 2 , Giuseppe Argenziano 3 and Lorenzo Cerroni 2 1 Pathologic Anatomy Service, Gaetano Rummo General Hospital, Benevento, Italy 2 Department of Dermatology, Medical University of Graz, Graz, Austria 3 Department of Dermatology, Second University of Naples, Naples, Italy Gerardo Ferrara, MD, Pathologic Anatomy Service, Gaetano Rummo General Hospital, Via dell’Angelo 1, I-82100 Benevento, Italy Tel: 139 082457315 Fax: 139 082457334 e-mail: gerardo.ferrara@libero.it Accepted for publication June 30, 2007 The diagnosis of early mycosis fungoides (eMF) is one of the greatest challenges in clinical dermatol- ogy and dermatopathology. In order to promote a standardized approach to this problem, the International Society for Cutaneous Lymphomas (ISCL) proposed in 2005 a diagnostic algorithm for eMF in its classical presentation; 1 such an algorithm is based on a scoring system involving the following clinical, histopathologic, biomolecular and immuno- pathologic criteria: 1. Basic criteria: clinical picture characterized by persistent and/or progressive patches/thin Present address: Iris Zalaudek, Department of Dermatology, Second University of Naples, Naples, Italy. 549