Pyoderma gangrenosum complicated with myelodysplastic syndrome followed by rapidly progressing pyothorax-associated lymphoma: a case report.

This report describes a patient with pyoderma gangrenosum (PG) complicated with myelodysplastic syndrome (MDS) followed by rapidly progressing pyothorax-associated lymphoma (PAL). A 74-year-old man was admitted with cutaneous gangrene associated with MDS. We diagnosed him as having PG, and high-dose oral prednisolone was started. Two months after admission he developed lymphoma rapidly. The patient died in spite of radiation therapy. On autopsy, the pathological diagnosis was diffuse large cell lymphoma. Epstein-Barr virus (EBV)-encoded RNA, and EBV-encoded nuclear antigen (EBNA) were detected in lymphoma cells. This case suggested that immunosuppressive therapy might favour the clonal proliferation of EBV-infected cells.