Ronen S, McAfee JL, Curry JL, Nagarajan P, Aung PP, Ivan D, Prieto VG, Tetzlaff MT, Torres-Cabala C. Phenotypic switch in mycosis fungoides: A tertiary cancer center experience.
Hum Pathol 2023;
142:27-33. [PMID:
37977511 DOI:
10.1016/j.humpath.2023.10.005]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/23/2023] [Accepted: 10/30/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND
Changes in immunophenotype in mycosis fungoides (MF) are rarely reported, making this phenomenon a diagnostic challenge with unclear significance for the disease's biological behavior. This study examines a large series of MF patients who exhibited a phenotype switch (PS) and analyzes their clinical and histopathologic characteristics.
DESIGN
Institutional files were searched for MF cases exhibiting PS between 2010 and 2020. Clinical, follow-up, and histopathological data were collected.
RESULTS
Forty-two biopsies from 32 patients (13 women and 19 men, median age 67.5) showed PS. Eight patients (25 %) experienced multiple PS during their disease course. The median time for PS was 22 months from the initial diagnosis. In 5 cases tested, identical TCR clone peaks were detected in the immunophenotypically distinct lesions. Median follow-up was 14.5 months. Among deceased patients, median time from MF diagnosis to PS was 20.6 months, while among the patients who were still alive, median time was 44.1 months.
CONCLUSION
MF biopsies can show PS during the course of the disease and may indicate a change in clinical behavior. 28.1 % of patients displayed more than one PS, further indicating high plasticity of MF cells. No obvious association was found between PS and therapy initiation or response. Features that appeared to portend a worse clinical course were earlier PS in the course of the disease and PS from CD4-/CD8-to CD8+, and CD8+ to CD4-/CD8-. Awareness of this phenomenon is crucial to avoid misdiagnosing phenotypically distinct lymphomas as second primaries and to alert clinicians about potential changes in the disease's clinical course.
Collapse