Pyoderma Gangrenosum in a 75-Year-Old Male With Follicular Diffuse Large B-cell Lymphoma.

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis that characteristically presents with progressive ulcerative lesions. The association of PG with hematological malignancies remains unclear due to its varied clinical presentation. Herein, we report the unusual case of PG in a 75-year-old male with stage III follicular diffuse large B-cell lymphoma. Seven days subsequent to his first dose of rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone (R-CHOP) therapy, he presented to the emergency department with generalized malaise, bilateral lower extremity edema, and ecchymoses with ulcerative wounds on the dorsal of his feet. Due to the rapid progression of the patient's dermatological manifestations and declining clinical status, he required serial surgical wound debridement and a biopsy, which revealed an occlusive vasculopathy with dermal and epidermal necrosis. These pathological findings, along with the patient's clinical presentation, led to the diagnosis of PG. The patient was treated with negative pressure wound therapy, steroids, and tacrolimus ointment, which led to a marked improvement in the appearance of the patient's dermatological features and clinical status.