Tubulocystic Carcinoma of the Kidney

Abstract

The nature of tubulocystic carcinoma, a rare renal tumor composed of tubular and cystic structures, is poorly understood. It has been suggested that it may represent a low-grade collecting duct carcinoma of the kidney despite the lack of sufficient molecular and pathologic evidence. The aim of this study was to examine the clinical and pathologic features of 13 cases of tubulocystic carcinoma of the kidney. Furthermore, using gene expression microarray analysis, we defined the molecular signature of this tumor by comparing it with other renal tumors in our previously established molecular profile database. Histologically, all 13 tumors were composed of closely packed tubules and cysts of varying sizes separated by fibrovascular septa. The epithelial lining cells of the tubules and cysts in this tumor were characterized by abundant eosinophilic cytoplasm with prominent nucleoli often showing a hobnail appearance. Clinically, one of the 13 cases showed metastasis to the pelvic lymph nodes. Five of the 13 cases coexisted with papillary renal cell carcinoma (RCC) (n=3) or papillary adenoma (n=2). In addition, the molecular profile of tubulocystic carcinoma was similar but not identical to those of papillary RCC by clustering analysis. Through comparative genomic microarray analysis, tubulocystic carcinoma showed gains of chromosome 17, but not chromosome 7, whereas most papillary RCCs showed chromosomal gains in both 7 and 17 (trisomies). Therefore, based on its unique pathologic features and molecular signature as well as its biologic behavior to develop metastasis either by itself or in association with papillary RCC, tubulocystic carcinoma of the kidney should be recognized as a distinct subtype of RCC and be distinguished from other malignant and benign cystic lesions of the kidney.

Tubulocystic Carcinoma of the Kidney with Fatal Outcome in an Adolescent Male

“…Most tumors occur in the left kidney (65%) and are Fuhrman nuclear grade 3, as also seen in our case [6]. Age generally ranges from 29 to 94 years [6], except in the case reported by Deshmukh et al [7], where the patient was an 18-year-old female. To the best of our knowledge, the case of our 15-year-old is the youngest described to date.…”

“…From the currently available data, most patients diagnosed with TCK are men with a ratio of 7:1 [6]. Most tumors occur in the left kidney (65%) and are Fuhrman nuclear grade 3, as also seen in our case [6].…”

“…In 1997, MacLennan et al [5] described 13 unusual cases of low-grade collecting duct carcinoma of the kidney with characteristically less aggressive behavior than Bellini duct carcinoma. In 2008, Yang et al [6] reported the molecular profile of TCK and found more similarities to pRCC by clustering analysis than to collecting duct carcinoma and renal medullary carcinoma. The same group was able to differentiate the two tumors using genomic microarray analysis: TCK showed gains of chromosome 17 but not of chromosome 7, whereas most pRCCs showed gains in both chromosome 17 and 7 [6].…”

Tubulocystic renal cell carcinoma in the left kidney: a case report

“…Therefore, an evolving concept of collecting duct carcinomas was proposed, and low-grade collecting duct carcinoma at the beginning of the spectrum corresponds to the current TCRC [5]. However, by using molecular clustering, TCRC was found to be more closely related to papillary RCC than to any other renal neoplasm such as collecting duct carcinoma [6]. Supportive findings include the expression of proximal convoluted tubule markers (CD10 and alpha-methylacyl-CoA racemase; AMACR), distal nephron proteins (parvalbumin, high-molecular-weight CK, and CD19) [3,7], and the detection of intercalated cells and cells similar to those in the proximal tubule and by using electron microscopy [3,8,9].…”

Genome-wide methylation analysis of tubulocystic and papillary renal cell carcinomas

“…Mostly, such tumors are composed of tubules and cysts lined by a single layer of typical hobnail cells with large nuclei and prominent nucleoli. The literature describing biological behavior, immunohistochemical profiles, ultrastructural features and possible differential diagnostic features of TRCC is limited [2][3][4][5][6]. The oncogenesis of this neoplasm is unclear.…”