BI11 Cutaneous presentation of Kaposi sarcoma following allogeneic haematopoietic stem cell transplantation for myeloma

Abstract

Abstract Iatrogenic Kaposi sarcoma (KS) is a relatively frequent occurrence following solid-organ transplants (0–5%), in part due to prolonged immunosuppression. However, its occurrence after haematopoietic stem cell transplantation (HSCT) is rare, with only 15 cases described in the literature. We report a case of KS presenting in the skin of a patient who had received a matched unrelated donor allogeneic HSCT for IgG kappa myeloma. A 55-year-old HIV-negative white man with myeloma underwent an allogeneic HSCT from a matched, unrelated donor following conditioning chemotherapy with fludarabine–melphalan and antithymocyte globulin. Post-transplant, he was maintained on ciclosporin as graft-versus-host disease (GVHD) prophylaxis. On day 14 post-transplant, he developed a widespread eczematous eruption that rapidly evolved into an erythroderma; a skin biopsy was consistent with acute GVHD. He was managed with superpotent topical steroids and a 5-day course of oral prednisolone. He began extracorporeal photopheresis (ECP) on day 33 post-transplant, having failed to respond adequately to systemic steroids. He also completed four cycles of rituximab. Ciclosporin was stopped by day 130 post-transplant. He had completed 14 cycles of ECP by day 139 post-transplant, with resolution of cutaneous GVHD; however, he had developed a rapidly growing solitary dusky-red nodule on his right neck that was excised due to diagnostic uncertainty. Histology revealed a dermal haemorrhagic exophytic vascular tumour composed of lobules and sheets of epithelioid cells with an eosinophilic cytoplasm and pleomorphic nuclei. Immunoperoxidase staining was negative for S100, MNF-116 and AE1/AE3. The same cells were strongly and diffusely positive for the vascular markers CD31, CD34 and ERG. The lesional cells were positive for human herpesvirus (HHV)-8 confirming a diagnosis of Kaposi sarcoma. He subsequently developed a second lesion on his left forearm, despite being off all immunosuppression. A repeat bone biopsy confirmed that he remains in morphological remission from his myeloma. Positron emission tomography–computed tomography has not identified extracutaneous disease. KS following HSCT is rare, but it can be fatal. Skin lesions are the dominant clinical presentation. HHV-8 has an important role in the pathogenesis, and transplant-related KS may occur secondary to reactivation of the virus as a result of significant immunosuppression following HSCT. However, it could also occur as primary infection or be transmitted with donor cells. The outcome of KS after HSCT is variable. A watch and wait strategy can be applied if immune recovery is expected. In our patient, it developed 5 months after HSCT; shortly after immunosuppression had been tapered, he remains well and will be closely monitored for further suspicious lesions.