Methotrexate-associated primary cutaneous CD30-positive cutaneous T-cell lymphoproliferative disorder: a case illustration and a brief review.

Methotrexate (MTX) is a commonly used anti-metabolite agent. Increased risk of lymphoproliferative disorders (LPD) in patients with rheumatoid arthritis (RA) has been documented with the prolonged use of immunosuppressive medications such as MTX. This is thought to be the result of immune dysregulation and/or chronic immune stimulation. Most cases of LPDs regress following withdrawal of the offending immunosuppressive agent. We present an interesting and rare case of CD30 and EBV positive CD8 primary cutaneous anaplastic large cell lymphoma (PC-ALCL) in a 66-year-old African American woman. Patient had been on MTX for rheumatoid arthritis (RA) which was stopped after the patient was evaluated at our institution. Patient had an incredible response to stopping immunosuppression with spontaneous regression of skin lesions and disappearance of clonal malignant cell population as evidenced on serial biopsy specimens. Primary cutaneous CD30+ LPDs constitute about 30% of the primary cutaneous T-cell lymphomas (CTLs) and includes entities such as lymphomatoid papulosis (LyP), primary cutaneous anaplastic large cell lymphoma (PC-ALCL) and other CD30+ borderline LPDs. Histopathological criteria in addition to CD30 positivity is important for identification of these conditions. Treatment options include "wait and see", phototherapy, radiotherapy, topical agents, systemic therapy and surgical resection. Prognosis is excellent and most cases resolve spontaneously on withdrawal of immunosuppression. Refractory cases may require aggressive local treatment or systemic therapy. Brentuximab Vedontin, an anti-CD30 antibody drug conjugate (ADC), may provide additional therapeutic option in refractory cases.