Primary cutaneous CD30 positive T-cell lymphoproliferative disorders with aberrant expression of PAX5: Report of three cases

Accurate diagnosis of lymphoma includes the assessment of lineage-specific markers. Hematopoietic and lymphoid tissues express PAX5 exclusively in pro-B-cell to mature B-cell stages. However, some mature PAX5+ T-cell lymphomas have been reported. We report three cases of primary cutaneous CD30+ T-cell lymphoproliferative disorders (LPDs) with PAX5 expression: one cutaneous anaplastic large cell lymphoma (ALCL) and two cases of lymphomatoid papulosis (LyP). The three patients were 26 years old and female, 75 years old and female, and 65 years old and male. In all cases, Hodgkin's and Reed-Sternberg-like large lymphoid cells were present, positive for CD30, fascin, and PAX5, and negative for CD3, CD4, CD8, CD20, CD45RO, CD56, cytotoxic markers, and Epstein-Barr virus. The ALCL was accompanied by lymphadenopathy; the patient died of progressive disease 5 months after diagnosis. The LyP cases were localized in the skin with spontaneous regression. One case was diagnosed during pregnancy, transformed to ALCL, and ended in death 32 months after diagnosis despite multi-agent chemotherapy. This study is the first to address the clinical significance of PAX5+ primary cutaneous CD30+ T-cell LPDs. These cases were distinct regarding PAX5 expression and a relatively aggressive clinical course versus conventional primary cutaneous CD30+ T-cell LPDs.