Hybrid tumour ‘oncocytoma‐chromophobe renal cell carcinoma’ of the kidney: a report of seven sporadic cases

Abstract

OBJECTIVES To determine whether renal hybrid tumours (HT) appear as a specific clinical and radiological entity, as HT are characterized by the association of both oncocytes and chromophobe cells within the same tumour, and have been described in patients with oncocytosis and Birt‐Hogg‐Dube syndrome. PATIENTS AND METHODS We reviewed the medical charts of 67 patients who had a partial or radical nephrectomy in our institution for renal oncocytoma (RO, 24), chromophobe renal cell carcinoma (CRCC, 36) and HT (seven), from January 2006 to October 2007. We report the clinical, radiological and pathological characteristics of the seven cases of HT. RESULTS The mean (range) age of the patients was 56 (41–68) year. None of the seven patients had any suspicion of RO, based on computed tomography (CT). Two patients had a history of kidney cancer. Five patients had partial and two a radical nephrectomy. The mean (range) maximum tumour diameter was 5.5 (1.8–9) cm. Two tumours were pT1a, two were pT1b and three were pT2. Pathological analysis showed RO‐like and CRCC‐like cells intermixed (six patients) or distinct (one). After a median (range) follow‐up of 20 (8–25) months, none of the patients had any evidence of disease recurrence. CONCLUSIONS In a large series of patients with sporadic RO and CRCC, 10% of the tumours had hybrid morphological features, as described in oncocytosis and Birt‐Hogg‐Dube syndrome. We were unable to identify any specific clinical characteristic. Most importantly, none of these HT showed any of the radiological characteristics of RO.

Expression of the Na+/K+-transporting ATPase gamma subunit FXYD2 in renal tumors

“…Alternatively, these oncocytomas may represent hybrid tumors. 22,23 It is intriguing that the distal tubule-specific protein FXYD2 is preferentially expressed in chromophobe RCC when both chromophobe RCC and oncocytoma are thought to derive from the distal nephron. Previous investigations using mRNAexpression analysis demonstrated that chromophobe RCC shows increased expression of distal nephron genes when compared with oncocytoma.…”

Sporadic hybrid oncocytic/chromophobe tumor of the kidney: a clinicopathologic, histomorphologic, immunohistochemical, ultrastructural, and molecular cytogenetic study of 14 cases

“…However, conventional (and pure) clear cell carcinomas, oncocytomas, chromophobe renal cell carcinomas, and papillary renal cell carcinomas have also been reported in the setting of BHD [9,10]. Recently, three small series of sporadic HOCT have been published [11][12][13], but without any chromosomal or molecular genetic studies.…”

“…In a recently published series of sporadic HOCT [11][12][13], no data on numerical chromosomal anomalies have been provided. Our series showed multiple numerical chromosomal aberrations, both monosomic and polysomic.…”

Identification of immunohistochemical biomarkers that differentiate chromophobe renal cell carcinoma from renal oncocytoma through molecular profiling of renal tumours

“…RO and chRCC are often considered to be extremities of the same morphological spectrum (Delongchamps et al 2009). Proper differentiation largely relies on haematoxylin and eosin (H&E) histochemistry of sections, and an experienced histopathologist to discern the characteristic histomorphologic features that separate the two entities.…”

“…Due to considerable morphological and histological overlap between the two entities, they are often considered to be extremes of the same morphological spectrum (Delongchamps et al 2009). Accurate differentiation between benign RO and malignant chRCC will obviously lead to better patient management and follow-up strategies in the clinical setting.…”