Pyoderma Gangrenosum (PG) is often associated with an underlying disease. PG as a paraneoplastic disease is illustrated by the presentation of four patients with malignancy of myeloproliferative origin and PG. An associated malignancy is found in approximately 7% of patients with PG, most commonly haematologic in nature and in particular leukaemia. Clinically the PG is often of the superficial bullous variant and is associated with a poor prognosis.