Papillary RCC and oncocytoma: Longer follow-up reported

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Dear Editor, We read with great interest the recent case report by Özer and colleagues,¹ in which the very rare occurrence of a concomitant papillary renal cell carcinoma and oncocytoma is described. The article highlights the fact that oncocytomas arise from intercalated cells of the collecting ducts and that papillary carcinomas have a different cellular origin; thus the finding of these two separate tumours within a single kidney is exceptionally rare and this is the fourth case described in the literature.

Reliable radiological confirmation of oncocytomas remains difficult, as tomography is frequently unable to distinguish between malignant renal lesions and “benign” oncocytomas,² and the definitive diagnosis is usually based on final pathological analysis. However, Cornelis and colleagues³ have explored the possibility that absence of central area signal inversion or the presence of a signal drop on chemical shift MRI may assist in ruling out oncocytomas.

We published a case of concomitant oncocytoma and papillary renal cell carcinoma in 2011⁴ in a 73-year-old female who presented with hypercalcaemia and was successfully treated with a left partial nephrectomy. The incidental finding of hypercalcaemia may not have been due to a paraneoplastic syndrome as the patient underwent excision of a parathyroid adenoma later in 2011.

We had originally operated on this case in 2009 and in light of the recent case described we have reexamined our patient’s postoperative surveillance. We now have 5 years of follow-up with no recurrence detected (of her left renal tumour) between 2009 and 2014, with the last upper tract ultrasound performed in May 2014 – 54 months following her partial nephrectomy. The patient’s serum creatinine is normal. Therefore, although Özer and colleagues¹ claim to have the longest follow-up at 18 months following concomitant oncocytoma and papillary cell carcinoma treated with radical nephrectomy, we have a similar case that remains tumour-free, based on radiological grounds, almost 5 years following partial nephrectomy.