Hodgkin's lymphoma in a patient of psoriasis treated with long-term, low-dose methotrexate therapy.

Methotrexate (MTX) is used in the treatment of a variety of diseases such as rheumatoid arthritis, dermatomyositis, juvenile rheumatoid arthritis and chronic plaque psoriasis. It has been well documented that there is a risk of development of lymphomas in these patients although none have been reported in patients of psoriasis treated with methotrexate. A 58-year-old male patient, a known case of psoriasis since 1994, had been receiving treatment with a low dose of MTX, 5 mg weekly for ten years intermittently (7-8 months/year). The cumulative dose of MTX taken was 1.5 gm. He developed high-grade fever with cervical lymphadenopathy that was nonresponsive to routine line of management. Lymph node biopsy revealed the presence of mixed cellularity type of Hodgkin's lymphoma. CT scan showed cervical, mediastinal and abdominal lymphadenopathy. The patient responded well to withdrawal of MTX and chemotherapy. This is the first case of lymphoma occurring in a patient of psoriasis treated with low-dose MTX.