Summary

We report a man who underwent autologous stem cell transplantation (ASCT) for multiple myeloma. Two months after ASCT, he presented with necrotising cholecystitis due to gallbladder stones and was submitted to laparoscopic cholecystectomy. About a week later, he developed progressive skin ulcers at sites where trochanters had been inserted. Progressive enlargement and necrotic aspect of these ulcers took place despite debridement and large spectrum antibiotics. New ulcers developed at the site of enoxaparin injection at the right arm (pathergy phenomenon). A skin biopsy and clinical evaluation favoured the diagnosis of pyoderma gangrenosum (PG). He was treated with daily methylprednisolone and dapsone with improvement of the lesions. This is the first case in the literature of PG after ASCT. Despite the risk factors, the onset of an autoinflammatory disease right after the transplant is intriguing since PG is extremely rare in immunocompromised patients.