ORIGINAL PAPER Clinical, Histopathological, Immunophenotypic and Molecular Analysis of 60 Patients with Cutaneous T-cell Infiltrates with Follow up of Indeterminate Cases to Identify T-cell Lymphoma Nóra Erős & Zsuzsánna Károlyi & Márta Marschalkó & Sarolta Kárpáti & András Matolcsy Received: 26 June 2007 / Accepted: 14 February 2008 / Published online: 8 April 2008 # Arányi Lajos Foundation 2008 Abstract Diagnosis of primary cutaneous T-cell lympho- mas, especially of mycosis fungoides could be difficult in early stage due to clinical and histopathological similarity to reactive inflammatory dermatoses. To assess diagnostic value of complex histological, immunophenotypic and T- cell receptor γ gene rearrangement analysis, skin biopsy specimen and peripheral blood samples of 60 patients with suspected cutaneous T-cell lymphoma were analyzed. Our results indicate clear distinction between reactive dermato- ses (benign cases, n =31) and cutaneous T-cell lymphomas (lymphoma cases, n =17). As definite diagnosis was not obtained in a smaller group of patients (indeterminate cases, n =12), these patients were followed up. Repeated skin biopsy confirmed mycosis fungoides in 6/12 cases, however in 6/12 patients the diagnosis remained indeter- minate. We concluded that careful and complex clinical follow up and repeated histopathological, immunopheno- typic and molecular analysis is needed for an appropriate diagnosis in the assessment of early stage mycosis fungoides and uncertain clinical cases. Keywords Cutaneous T-cell lymphoma . Mycosis fungoides . Cutaneous T-cell infiltrate . Histopathology . Immunophenotype . Molecular biology Abbreviations PCR Polymerase chain reaction TCR T-cell receptor Introduction Incidence of cutaneous T-cell lymphomas has been increased worldwide over last decades partly due to recent advances in diagnostic procedures. Accurate diag- nosis could be established by simultaneously performed histological, immunophenotypic and gene rearrangement analysis, however diagnosis of early stage mycosis fungoides remained an important diagnostic problem in dermatopathology. Many cutaneous lymphomas develop with rapidly growing skin tumors, so remarkable clinical presentation leads to early skin biopsy and histopathological examina- tion. However mycosis fungoides has slow evolution from erythematous scaly patches resembling benign dermatoses such as eczema, psoriasis or fungal infections, so histo- pathological confirmation of the malignant process may delay even for years. Histopathological findings in early patch stage of mycosis fungoides are often nonspecific. Disproportionate Pathol. Oncol. Res. (2008) 14:63–67 DOI 10.1007/s12253-008-9014-3 Supported by grants from the Hungarian National Science Foundation OTKA T032572, T034410 and from the Hungarian Ministry of Health ETT 144/2003. N. Erős(*) : M. Marschalkó : S. Kárpáti Department of Dermatology, Venerology and Dermatooncology, Semmelweis University, Faculty of Medicine, Mária str. 41, 1085 Budapest, Hungary e-mail: dr.eros@citromail.hu Z. Károlyi Department of Dermatology, Semmelweis Hospital, Miskolc, Hungary A. Matolcsy 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Faculty of Medicine, Budapest, Hungary