A 63-year-old HIV-negative homosexual man was treated for 16 weeks with mycophenolate mofetil for biopsyproven membranous glomerulopathy with nephrotic proteinuria. An extensive search for a viral or malignant cause for the membranous glomerulopathy had not shown any possibilities other than immunity against hepatitis B virus (negative for hepatitis B surface antigen [Hbs-Ag] and for antibodies against hepatitis B e antigen [anti-Hbe], positive for antibodies against hepatitis B core and surface antigens [anti-Hbc and anti-Hbs, respectively]). Antibodies against HIV types 1 or 2 were absent (microparticle enzyme immunoassay HIV1/2, Abbot Diagnostic Division, Hoofddorp, Netherlands). Mycophenolate mofetil was discontinued in November, 2004, because of noncompliance. Earlier in the course of his disease, the patient was given corticosteroids, which were stopped because the patient did not show a clinical response and had psychiatric adverse eff ects. Several months after mycophenolate mofetil was stopped, he developed a few skin lesions on both wrists. Excisional biopsy of a skin lesion showed spindle cells compatible with Kaposi’s sarcoma. Immunohistochemical staining showed expression of human herpesvirus 8 (HHV8). Immunohistochemical staining for HHV8 of the former renal biopsy was negative. Treatment did not yet seem warranted. In March, 2005, he underwent an axillobifemoral bypass after occlusion of an aorta-bifemoral bypass. Because of an infectious complication, the wound in his left groin was re-explored. Soon after, he developed rapidly progressive Kaposi’s sarcoma on both legs. The largest lesions appeared near to the surgical wound (fi gure A). HHV8 PCR showed 10 000 copies/mL but repeated tests for HIV infection remained negative. Immunoglobin concentrations and the ratio of CD4 to CD8 cells were normal. Subsequently, severe lymphoedema developed in his left leg (fi gure B), which was complicated by recurrent episodes of erysipelas. Repeated courses with amoxicillin and clavulanic acid, or fl ucloxacillin, were given successfully. Blood, urine, and wound cultures remained negative. Deep venous thrombosis or occlusion of the arterial bypass was excluded with repeated ultrasonography and magnetic resonance angiography. Because the Kaposi’s lesions were extensive and located around a surgical wound covering an arterial bypass, systemic treatment seemed warranted. Radiotherapy was not an option. Chemotherapy was contraindicated because of his poor performance status, renal failure, and the infected wound. Inspired by a report in kidney transplant recipients, we started the patient on a course of low-dose sirolimus (target blood concentration 5 μg/L). After 6 weeks, lymphoedema and skin lesions clearly regressed and some lesions spontaneously ruptured. HHV8 viral load was not signifi cantly altered (from 1×10 to 0·6×10 copies/mL). During the following months, the lesions continued to regress (fi gure), and kidney function decreased from a calculated creatinine clearance of 12 mL/min to 9 mL/min (<1 mL/min per month). In the months before the start of sirolimus treatment, creatinine clearance decreased with a rate of about 2 mL/min per month. Proteinuria was massive (13 g per 24 h) but stable, and total cholesterol concentrations remained in the high normal range with statin therapy. However, 6 months after the start of sirolimus treatment, end-stage renal failure ensued (as expected Lancet Oncol 2006; 7: 875–76