Mass lesions in the transplanted kidney: Questions

Excerpt

A 14 year-old female patient presented with fever, nausea, and dysuria. Her medical history included spina bifida and neurogenic bladder. She was on intermittent catheterization through her appendicovesicostomy. Over time, she developed reflux nephropathy and progressed to end-stage renal disease (ESRD), at which point she was started on peritoneal dialysis. She had bilateral nephrectomy and received a deceased-donor kidney transplant 1 year before this presentation. Her maintenance immunosuppression included prednisolone, mycophenolate mofetil, and tacrolimus. She developed two episodes of Escherichia coli urinary tract infection 1 and 4 months after transplant. Vital signs were as follows: blood pressure (BP) 118/65 mmHg, pulse rate (PR) 110/min, respiratory rate (RR) 18/min, and temperature (T) 38.5 °C. Physical examination was unremarkable except for mild renal allograft tenderness. Laboratory investigations were as follows: white blood cell count (WBC) 2,300/ul [polymorphonuclear leukocytes (PMN) 63 %, lymph 32 %, mononuclear leukocytes (mono) 3 %], hemoglobin (Hb) 7.6 g/dl, platelet 284,000/µl, blood urea nitrogen (BUN) 12 mg/dl, serum creatinine (sCr) 1.3 mg/dl (baseline 0.9 mg/dl), and C-reactive protein (CRP) 13.8 mg/dl (normal range 0–1 mg/dl)]. Urinalysis showed ten WBCs/high power field (HPF) and positive for nitrite. Renal sonogram of the allograft was performed and showed two complex, solid, and cystic mass lesions with internal vascularity at the upper and lower poles of the transplanted kidney (Fig. 1). Magnetic resonance imaging (MRI) revealed three large, complex masses with solid and cystic components in the transplanted kidney, with the largest measuring up to 5.6 cm in the inferior pole (Fig. 2). There were additional smaller, oval, subcentimeter masses scattered throughout the kidney. Renal allograft biopsy was performed by interventional radiology for tissue diagnosis. Pathology finding are shown in Figs. 3 and 4.

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