Primary Cutaneous Peripheral T-Cell Lymphoma With Aberrant Coexpression of CD20: Case Report and Review of the Literature

Abstract

We report an unusual case of primary cutaneous T-cell lymphoma in a 45-year-old male showing expression of the B-cell marker CD20. The lesion presented as a large plaque on the right shin and rapidly developed into additional lesions on the right lower leg and right anterior chest. Despite therapy, bone involvement was discovered at 1 year after initial presentation. Punch biopsy of the right leg revealed a diffuse, atypical dermal lymphocytic infiltrate with papillary edema and no epidermotropism. The atypical cells strongly expressed the T-cell markers CD3, CD2, and CD43, with additional expression of cytotoxic T-cell markers CD8, cytotoxic granule-associated RNA binding protein (TIA-1), and granzyme B and loss of CD7 by immunohistochemistry (IHC). In addition, the atypical cells with the above phenotype exhibited moderate expression of CD20 by IHC. Coexpression of CD8 and CD20 in the atypical cells was confirmed by a dual-labeled IHC stain. Clonal rearrangements of the T-cell receptor gamma- and beta-chain genes were detected by polymerase chain reaction; however, there was no expression of T-cell receptor beta-chain identified by IHC. In conclusion, we present a case a of CD8-positive primary cutaneous T-cell lymphoma with CD20 expression, exhibiting aggressive behavior.

Concomitant Occurrence of Kimura Disease and Mycosis Fungoides in a Lebanese Woman: Significance and Response to Rituximab

“…Finally, the sustained improvement of MF to rituximab in this patient is hard to explain especially in view of the absence of aberrant CD20 coexpression by neoplastic T cells, a finding that has been rarely reported in primary cutaneous T-cell lymphomas. 24 …”

Pitfalls in the Diagnosis of Cutaneous Lymphoma

“…116 This dual genotype occurs either because of lineage infidelity (a single clone of cells exhibiting both rearrangements) or occurrence of 2 distinct clones in the same lymphoma (first, phenotypically neoplastic cells of particular lineage and second, an oligo or monoclonal clone of reactive cells of other lineage) 116,129 (Table 5). 132 1 PTL-U CD20 Absent Oshima et al 140 1 PTL-U CD20 Absent Balmer et al 141 1 PTL-U CD20 Absent Lee et al 108 1 PTL-U CD20, CD79a Neck lymph node involvement Martin et al 114 1 PTL-U CD20 Absent Martin et al 114 1 MF CD20 Absent Sen et al 115 1 MF CD20 Inguinal lymph node involvement Rahemtullah et al 106 2 MF CD20 Absent Garcia-Herrera et al 25 1 Despite a high prevalence of 50% (2 of 4) 116 and 20% (4 of 13) 130 of dual genotypes in Sezary syndrome found in 2 studies, very few cases of bigenotypic cutaneous lymphomas have been cited in literature. In a large series by Kazakov et al, 129 the dual genotype was seen in only 1% of primary cutaneous lymphomas.…”

Cutaneous Lymphoma at Injection Sites

“…However, a T-cell origin was suspected since the case closely resembled previous lymphomas described in humans. 3,46 Indeed, CD20-positive T-cell lymphomas are frequently reported in humans. 3,49,58 These results further heighten that CD20 should not be considered a lineagespecific B-cell marker and should not be used alone to identify neoplastic B cells.…”