Review of tubulocystic carcinoma of the kidney with focus on clinical and pathobiological aspects

Abstract

Tubulocystic carcinoma of the kidney (TCK) is a recently established entity in renal neoplastic pathology. This review aims to give an overview of the clinical and pathobiological aspects of TCK. Grossly, the TCKs are well-demarcated multicystic lesions giving a "wrapped bubble" or "spongy" appearance. Microscopically, the tumors are composed of multiple, variably sized cysts separated by thin fibrous septa lacking ovarian stroma or desmoplastic reaction. The cysts are lined by tumor cells with eosinophilic cytoplasm and nuclear atypia of variable, but not infrequently of high grade corresponding to Fuhrman grade 3. A frequent association with papillary tumors has been reported. Recent molecular genetic studies of TCK have revealed distinct features separating this subset of renal cell carcinomas (RCCs) from other types of renal tumors including collecting duct carcinoma of Bellini and renal medullary carcinoma as well as pointing towards a close kinship with papillary RCC. Tubulocystic carcinoma of the kidney generally pursues an indolent clinical course. However, several cases with aggressive clinical behavior have been reported. We strongly feel that there is enough clinicopathological evidence to corroborate TCK as a separate entity and that it should be incorporated into the next WHO classification of renal tumors as a separate neoplastic category.

Metanephric adenoma of kidney: a rare and distinct entity

“…2,3 Follow up is short and not well documented in the literature however distant metastasis after 46 months of follow up post-surgery has been described. 2,10 CONCLUSION MA is a rare distinct benign tumor which can mimic other benign and malignant tumors.…”

“…1,7 Occasionally these tumours are responsible for paraneoplastic syndrome such as polycythemia. 3,7,8 Radiological studies mostly reveal well circumscribed mass lesion in kidney. Metanephric adenoma on USG shows hypoechoic lesion but some authors have found MA to be hyperechoic.…”

“…It is clear that, metanephric adenoma cannot be differentiated from other renal masses as there are no specific definitive radiologic findings. [2][3][4]9 On gross examination, size of MA ranges from 0.6-20 cm. 3,9 MA is usually well circumscribed but unencapsulated with no extra-renal extension and tan to grey color on cut surface.…”

“…2,5 Metanephric adenoma, first described by Bove et al is a recently characterized benign cortical renal tumor. 3 This tumour commonly affects patients in 6 th -7 th decades of life with slight female preponderance.…”

“…[1][2][3][4][5] According to WHO classification of renal tumours, metanephric adenoma, metanephric adenofibroma and metanephric stromal tumour forms metanephric group of renal neoplasms. 6 Less than 200 cases of metanephric adenoma are reported till date in the literature.…”