Late occurrence of an unusual tumour of left native kidney in an allograft recipient.

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A 62-year-old diabetic male with end-stage renal disease underwent live renal transplantation in March 2009 with 225 mg of thymoglobulin as induction. In May 2012, evaluation by a computed tomography (CT) scan for recurrent urinary tract infection (UTI) and left loin showed left native kidney neoplasm with para aortic node metastasis (Figure 1). His baseline creatinine was 123.76 μmol/L (1.4 mg/dL). Left radical nephrectomy revealed moderately differentiated squamous cell carcinoma (SCC) on histology. Sirolimus 1 md od was added to his immunosuppressant regime which included cyclosporine A 150 mg bd, prednisolone 5 mg od and mycofenolate mofetil 1 g bd. A positron emission tomography (PET) scan in June 2012 showed residual lesions in the postoperative bed infiltrating left psoas muscle and metastasis to tail of pancreas and penile urethra (Figure 2). Following this, cyclosporine was discontinued. He received radiotherapy for the pancreatic metastasis and underwent excision of the urethral nodule with perineal urethrostomy. In September 2012, a revision of the perineal urethostomy was done to relieve an obstruction of the neo-meatus which had been causing repeated urinary tract infection. The rapamycin trough level was 3.98 nmol/L (4.79 ng/dL), and serum creatinine was 114.92 μmol/L (1.3 mg/dL). The patient continues on radiotherapy and is having stable graft function. Fig. 1. CT scan showing SCC of left native kidney with para-aortic nodes. The allograft is also seen. Fig. 2. PET scan showing increased uptake by the urethral secondary and the urine in the bladder. Primary SCC of native kidney in a renal transplant recipient is very rare, with, to our knowledge, no reported cases in the literature so far. The pathogenesis of SCC is due to chronic irritation superimposed with infection which induces squamous metaplasia leading to leukoplakia and finally neoplasia [1]. This occurs in chronic calculi, analgesic abuse and radiotherapy [2], which was not the case in our patient. A radiological diagnosis of SCC is difficult due to the absence of specific characteristic signs [2], an accurate diagnosis is only possible on postoperative histological analysis or renal fine needle aspiration cytology [1].