[490] Prognostic Factors in Mycosis Fungoides with Large Cell Transformation

Melissa P Pulitzer, Patricia L Myskowski, Steven Horwitz, Steven Duzsa, Christiane Querfeld, Brian Connolly, Janet Li, Rajmohan Murali. Memorial Sloan-Kettering Cancer Center, New York, NY

Background: In mycosis fungoides (MF), large cell transformation (LCT-MF) is the histopathologic transformation of atypical lymphocytes to a clonally identical large cell phenotype, which occurs in 20-50% of advanced MF and less commonly in patch/plaque disease. LCT-MF is thought to be a histologic marker of poor prognosis, associated with a five-year survival of <20%. Some patients with LCT-MF have a more indolent course. We sought to identify clinico-pathologic prognostic factors in a large number of patients with LCT-MF.
Design: We identified patients with LCT-MF treated at a referral center for cutaneous lymphoma from January 1990 through March 2012, and who had histopathology slides available for review. Clinical charts were examined, and pathologic features analyzed by review of slides and reports on all available cases. Cases in which the diagnosis was not straightforward were reviewed by an interdisciplinary team for confirmation. Associations of clinico-pathologic parameters with disease-specific survival were analyzed.
Results: 51 patients with LCT-MF were identified. Factors significantly associated with shorter survival were: age>60 at diagnosis of MF (p=0.004) and at transformation (p=0.01); stage III/IV at transformation (p=0.03); concurrent transformation in skin and nodes (p=0.006); high LDH at transformation (p=0.01); presence of TCR beta (p=0.04) or gamma (p=0.03) gene rearrangements; high density of infiltrate after transformation (p=0.001); absence of papillary dermal involvement (p=0.04); presence of subcutaneous involvement at transformation (p=0.046); % large cells at transformation (p=0.05); and presence of follicular mucin at transformation (p=0.02). Factors significantly associated with a better outcome were: presence of epidermal hyperplasia (p=0.002), and fibrosis at transformation (p=0.04). Patients presenting with transformation at diagnosis had a better survival compared to those who start with a small cell phenotype (p=0.02).
Conclusions: In our patients with LCT-MF, values of standard clinical features (age, stage and LDH) were important prognostically. Further clinical and pathologic measures of tumor burden (transformation in viscera or skin/nodes synchronously, TCR rearrangements, density, subcutaneous involvement, dermal CD30, and mitotic activity), follicular mucin, and % LCT were also prognostic. Additional larger studies using multivariate models are needed.
Category: Dermatopathology

Monday, March 4, 2013 11:45 AM

Proffered Papers: Section F, Monday Morning


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