Papillary renal cell carcinoma embedded in an oncocytoma: Case report of a rare combined tumour of the kidney

Abstract

case report E513Cite as: Can Urol Assoc J 2013;7(7-8):e513-6. http://dx.doi.org/10.5489/cuaj.414 Published online on July 2, 2013. AbstractAn asymptomatic 1-cm large papillary renal cell carcinoma (RCC) embedded in a 3.5-cm large oncocytoma was diagnosed and removed by right nephrectomy in a 68-year-old male investigated for the abdominal symptoms associated with cholelithiasis. The papillary RCC displayed positive immunohistochemical stainings with cytokeratin 7, alpha-methylacyl-CoA racemase and vimentin and was negative for the E-cadherin and CD117 immunostains, whereas the oncocytoma part showed opposite staining patterns. No gains of chromosomes 7 and 17 or loss of chromosome Y was detected in the papillary carcinoma by fluorescent in situ hybridization with centromeric enumeration probes. This finding is in keeping with the morphologic diagnosis of type 2 papillary RCC reported to have lower rates of these characteristic chromosomal changes. The combination of papillary RCC and oncocytoma, two tumours of different postulated origin, is extremely rare. It may represent a simple coincidence, but 2 previous cases and our current one share a few features, including the intimate embedment of the papillary RCC in the oncocytoma, the small size of the RCC and the old age of the patients. This case raises the point that renal oncocytomas can contain a hidden malignant tumour. IntroductionRenal cell neoplasms are supposed to derive from or show differentiation toward different parts of the renal epithelium, as highlighted by immunohistochemical staining patterns and differential expression of some marker proteins.1-3 There are reports on renal tumours with hybrid features between chromophobe renal cell carcinoma (RCC) and oncocytoma, both thought to arise from the distal tubular epithelium. 4 Sometimes RCC arises within an oncocytoma. 5 However, the combination of oncocytoma and papillary RCC, 2 renal neoplasms of different origin, is very rare. 6,7 We present a case of an unusual combination of these 2 tumours, a papillary RCC buried in an oncocytoma. Case reportA 68-year-old male with long-standing hypertension was admitted to our hospital because of right upper abdominal pain. Abdominal ultrasound and computerized tomography (CT) revealed a thick-walled gallbladder with common bile duct stones and a 4-cm mass in the upper pole of the right kidney (Fig. 1). The clinical diagnosis of choledocholithiasis associated with acute cholecystitis and a renal tumour were established. After endoscopic sphincterotomy, the symptoms related to the common bile duct stone vanished and the patient underwent right nephrectomy.The nephrectomy specimen was fixed in 10% neutral buffered formalin for 36 hours. We embedded 3-mm-thick representative tissue sections in paraffin wax and sections of 4 to 5 µm were cut and stained with hematoxylin and eosin (H&E) for light microscopy. The primary antibodies used for immunohistochemistry are shown in Table 1. ResultsThe parenchymal tumour in the nephrectomy specimen was circumscribed, homoge...

Papillary renal cell carcinoma within a renal oncocytoma: Case report of very rare coexistence

“…1,11 Renal oncocytoma and RCC can coexist in the same or the contralateral kidney. 6 Chromophobe RCC and oncocytoma are suspected to be closely related and are thought to show a similar distal tubular phenotype. However, oncocytomas and papillary RCCs originate from different cells and the presence of a papillary RCC within an oncocytoma is extremely rare.…”

“…We were only able to identify 3 case reports with this coexistence. [4][5][6] All tumours were detected incidentally during imaging studies for other reasons and none of these were larger than 4 cm. Two of these cases were treated with partial nephrectomy and one with radical nephrectomy.…”

“…3 To our knowledge, only 3 cases of papillary subtype of RCC within a renal oncocytomahave been previously described in the literature. [4][5][6] In this case report, we present the fourth case of papillary RCC embedded in a renal oncocytoma.…”

Renal collision tumour of papillary cell carcinoma and chromophobe cell carcinoma with sarcomatoid transformation: A case report and review of the literature

“…7 On the basis of the pathological findings, the renal neoplasms was diagnosed as a collision tumour comprising papillary renal cell carcinoma (PRCC) and ChRCC with sarcomatoid transformation in the kidney; to our knowledge this is the first reported case. [2][3][4] RCC is a heterogeneous tumour that comprises different histological subtypes (based on morphology), including clear cell renal carcinoma, PRCC, ChRCC and collecting duct carcinomas. PRCC is the second-most common histological subtype, accounting for about 10% to 15% of all RCC.…”

Evolution of Pathological Staging and Histological Classification in Urological Malignancies

“…In our case the diagnosis of a combined tumour, a papillary renal tumour embedded in an oncocytoma was based on microscopic morphology and immunohistochemistry [77]. In certain regions the two tumour types were sharply divergent; in other foci they exhibited morphologies that were difficult to differentiate.…”