T-cell prolymphocytic leukemia: potential diagnostic pitfalls

• Published in: Annales de dermatologie et de vénéréologie 2014-12, Vol.141 (12), p.777-781
• Main Authors: Dessart, P, Lemaire, P, Le Dû, K, Sandrini, J, Prophette, B, Maillard, H
• Format: Article
• Language: fre
• Subjects: Adenocarcinoma - therapy; Aged; Antimetabolites, Antineoplastic - therapeutic use; Capecitabine - therapeutic use; Chromosome Deletion; Combined Modality Therapy; Delayed Diagnosis; Diagnostic Errors; Fatal Outcome; Humans; Immunophenotyping; Leukemia, Prolymphocytic, T-Cell - diagnosis; Leukemia, Prolymphocytic, T-Cell - drug therapy; Leukemia, Prolymphocytic, T-Cell - genetics; Leukemia, Prolymphocytic, T-Cell - pathology; Male; Neoplasms, Second Primary; Pentostatin - therapeutic use; Rectal Neoplasms - therapy; Sezary Syndrome - diagnosis; Skin Neoplasms - diagnosis; Skin Neoplasms - drug therapy; Skin Neoplasms - genetics; Skin Neoplasms - pathology; T-Lymphocytes - pathology
• ISSN: 0151-9638
• DOI: 10.1016/j.annder.2014.09.012

Sezary syndrome (SS) presents clinically as erythroderma, which may be pigmented, and pruritic, associated with peripheral lymphadenopathies. Erythroderma may also occur in a broad range of reactive and malignant conditions including T-cell prolymphocytic leukemia (T-PLL). We report a case initially diagnosed as SS but ultimately diagnosed as T-PLL based upon skin involvement. A 70-year-old man was referred by his hematologist for management of SS. Physical examination revealed lymphadenopathies and mild diffuse erythema without infiltration. His WBC count was elevated at 8.3 G/L. A peripheral blood smear showed Sezary-like cells. Flow cytometry of peripheral blood revealed prolymphocytic T-cells staining positively for CD2, CD3, CD4 and CD7. Cytogenetic studies showed chromosomal abnormalities in terms of number and structure with missing chromosomes 6 and13, as well as deletion of chromosome 17. Finally, a diagnosis of T-PLL was made. Pentostatin was initiated pending treatment with alemtuzumab, but the patient's overall condition deteriorated rapidly and he died 10 days later. Diagnosis of LPLT is based upon a number of factors. In the case presented herein, the clinically atypical nature of the skin lesions prompted the dermatologist to review the diagnosis. The morphology of the circulating T-lymphocytes and their immunologic and phenotypic characteristics finally ruled out the diagnosis of Sezary syndrome, while their association with compatible cytogenetic anomalies enabled a diagnosis of prolymphocytic leukemia to be made instead. Prolymphocytic leukemia involves complex differential diagnosis with regard to Sezary syndrome, posing potential pitfalls for hematologists and dermatologists.