CASE 16: Kaposi Sarcoma of the Urinary Bladder

44 year old female with a diagnosis of IgA nephropathy and FSGS (focal segmental glomerulo sclerosis) who underwent a live donor kidney transplant. Post-operatively she was treated for a borderline acute cellular rejection with C4d positivity. Seven months post-transplant she presented with a urinary tract infection that progressed to complaints of dysuria, flank pain, and fullness over the allograft despite broad-coverage antibiotics. A CT scan showed bladder thickening at the site of implantation of the ureter and retro-peritoneal lymphadenopathy (Figures 112-56–112-58). Biopsy of the bladder and of an enlarged lymph node revealed a spindle cell neoplasm with prominent vascular channels filled with red blood cells. Immunohistochemical stains confirmed Human Herpes Virus-8 (HHV-8) in the neoplastic cells and the diagnosis of Kaposi sarcoma (Figures 112-62–112-65).

Initial treatment was discontinuation of tacrolimus and mycophenolate mofetil, remaining only on 5 mg daily of prednisone. Pegylated liposomal doxorubicin was started. By the fourth cycle, all symptoms had resolved.

Follow-up CT scans of the abdomen and pelvis showed complete resolution of the findings (Figures 112-59–112-61).

Currently she is on low dose sirolimus and 5 mg prednisone with a normal creatinine.

This case is especially interesting because it occurred in a female, had no dermatologic manifestations, and involved the bladder.

As exemplified here, in the setting of immunosuppression all lesions should be biopsied unless a diagnosis is evident and undisputable.