[1556] Nodal Involvement by Transformed Cutaneous CD30-Positive T-Cell Lymphoma Mimicking Classical Hodgkin Lymphoma

Joo Y Song, Franziska C Eberle, Liqiang Xi, Mark Raffeld, Nancy L Harris, Wyndham H Wilson, Stefania Pittaluga, Elaine S Jaffe. NCI, Bethesda, MD; Massachusetts General Hospital and Harvard Medical School, Boston, MA

Background: Classical Hodgkin lymphoma (cHL) following mycosis fungoides (MF) or lymphomatoid papulosis (LyP) in the same patient has been debated in the literature. There is considerable morphologic and immunophenotypic overlap between cHL and nodal involvement of CD30-positive T-cell lymphomas (TCL). Whether such cases represent TCL with Hodgkin-like cells or cHL is often difficult to resolve.
Design: Biopsies from patients with a prior history of cutaneous TCL or primary cutaneous CD30-positive T-cell lymphoproliferative disorder and lymph node biopsies reported as either CD30-positive TCL with Hodgkin-like cells or cHL were retrieved from the authors' institution. We performed immunophenotypic and T-cell receptor gene rearrangement studies (TRG) in order to clarify the diagnosis. Laser capture microdissection (LCM) was performed in one case.
Results: Of 11 cases identified, 10 were considered CD30-positive TCL with Hodgkin-like cells, while one was confirmed as cHL upon review. Four cases originally diagnosed as cHL were revised as CD30-positive TCL. The CD30-positive TCL showed a male predominance (M:F, 4:1) with a median age of 53 years (range 44-72 years). 9/10 patients initially presented with skin lesions and later developed nodal involvement, although in some cases lack of knowledge of the cutaneous lesions led to a misdiagnosis of cHL In 8/10 patients the draining lymph node was involved, whereas in 2 cases generalized skin disease was present. Tumor cells morphologically resembled Hodgkin/Reed-Sternberg (HRS) cells, and were strongly positive for CD30 and negative for B-cell markers (i.e. PAX5, CD20) in all cases. Expression for CD15 was observed in the majority of cases (9/10). Also, 7/10 cases of CD30-positive TCL with Hodgkin-like cells had tumor cells that expressed at least one T-cell marker and all (9/9) cases studied revealed a clonal rearrangement by TRG. LCM in one case showed identical clones in skin and LN. In situ hybridization studies for EBV were negative for all studied cases. In one case the diagnosis of cHL followed by LyP was confirmed, with HRS-cells expressing PAX5, CD30 and CD15.
Conclusions: In some cases of transformed MF/LyP with nodal involvement, the distinction from cHL can be challenging, but combined morphologic, immunophenotypic, and molecular studies together with careful clinical correlations help to differentiate these lesions. Misdiagnosis as cHL remains a diagnostic pitfall.
Category: Hematopathology

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 188, Wednesday Morning

 

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