Renal angiomyoadenomatous tumor

Renal angiomyoadenomatous tumour

Renal angiomyoadenomatous tumour is a newly described rare neoplasm. This tumour is characterised microscopically by admixture of three components- epithelial cells arranged in tubules and nests, angiomyomatous stroma and capillary sized interconnecting vascular channels in close association with the epithelial cell clusters. Microscopically it has wide range of differential diagnoses which include mixed epithelial and stromal tumour of kidney, angiomyolipoma and clear cell renal cell carcinoma with angiomyolipomatous/angiomyoadenomatous areas. Renal angiomyoadenomatous tumour should be differentiated from these tumours. Till now, only 10 cases have been reported in English medical literature. Here, we are reporting a case of renal angiomyoadenomatous tumour in a 29 year- old female patient who presented with hematuria and low backache and describing its main features so as to differentiate this entity from other renal tumours. To the best of our knowledge, this is the first case to be reported from India.

Thyroid-Like Follicular Carcinoma of the Kidney

Thyroid-like follicular carcinoma of the kidney (TLFCK) is a rare but emerging renal neoplasm that morphologically mimics follicular carcinoma of the thyroid but lacks immunohistochemical expression of thyroid markers such as TTF-1 and thyroglobulin. Here, a case of an incidentally discovered TLFCK in a 27-year-old man is reported. Histologic evaluation demonstrated an encapsulated proliferation of variably sized thyroid follicle-like epithelial-lined spaces filled with colloid-like eosinophilic secretions. Immunohistochemical analysis confirmed lack of expression of the thyroid markers TTF-1 and thyroglobulin with expression of PAX8 and CD10, confirming a neoplasm of renal origin, which correlated to the clinical and radiographic absence of thyroid pathology. In this report, this case is described with an emphasis on the differential diagnosis.

Clear cell papillary renal cell carcinoma and renal angiomyoadenomatous tumor: two variants of a morphologic, immunohistochemical, and genetic distinct entity of renal cell carcinoma

Clear cell papillary renal cell carcinoma (ccpRCC) and renal angiomyoadenomatous tumor (RAT) share morphologic similarities with clear cell (ccRCC) and papillary RCC (pRCC). It is a matter of controversy whether their morphologic, immunophenotypic, and molecular features allow the definition of a separate renal carcinoma entity. The aim of our project was to investigate specific renal immunohistochemical biomarkers involved in the hypoxia-inducible factor pathway and mutations in the VHL gene to clarify the relationship between ccpRCC and RAT. We investigated 28 ccpRCC and 9 RAT samples by immunohistochemistry using 25 markers. VHL gene mutations and allele losses were investigated by Sanger sequencing and fluorescence in situ hybridization. Clinical follow-up data were obtained for a subset of the patients. No tumor recurrence or tumor-related death was observed in any of the patients. Immunohistochemistry and molecular analyses led to the reclassification of 3 tumors as ccRCC and TFE3 translocation carcinomas. The immunohistochemical profile of ccpRCC and RAT samples was very similar but not identical, differing from both ccRCC and pRCC. Especially, the parafibromin and hKIM-1 expression exhibited differences in ccpRCC/RAT compared with ccRCC and pRCC. Genetic analysis revealed VHL mutations in 2/27 (7%) and 1/7 (14%) ccpRCC and RAT samples, respectively. Fluorescence in situ hybridization analysis disclosed a 3p loss in 2/20 (10%) ccpRCC samples. ccpRCC and RAT have a specific morphologic and immunohistochemical profile, but they share similarities with the more aggressive renal tumors. On the basis of our results, we regard ccpRCC/RAT as a distinct entity of RCCs.

Clear cell-papillary renal cell carcinoma of the kidney not associated with end-stage renal disease: clinicopathologic correlation with expanded immunophenotypic and molecular characterization of a large cohort with emphasis on relationship with renal angiomyoadenomatous tumor

Clear cell-papillary renal cell carcinoma (CC-Pap RCC) is a recently described renal tumor initially reported in the setting of end-stage renal disease (ESRD). It has unique morphologic and immunohistochemical features that differentiate it from the more common clear cell RCC and papillary RCC. Recently, these tumors have also been described in a sporadic setting. We studied 64 cases of CC-Pap RCC not associated with ESRD (57 CC-Pap RCCs and 7 cases with features of renal angiomyoadenomatous tumors [RAT] including 5 initially diagnosed as such). The morphologic features of all cases and the immunohistochemical profile of 59 cases were studied along with the clinical and molecular features of 30 and 12 cases, respectively. All the tumors were well circumscribed with a mean tumor size of 2.6 cm and showed a wide array of architectural patterns, usually mixed, including tubular (77%), papillary (62%), tubulocystic (52%), and compact nested (21%). Seventy-three percent of the cases showed areas in which the tumor nuclei had a distinct orientation away from the basement membrane. Ninety-two percent of the cases had a low Fuhrman nuclear grade (nuclear grade 2%-86%, and nuclear grade 1%-6%); however, 8% cases showed foci of Fuhrman nuclear grade 3. In 4 cases, epithelial tumor comprised <5% of the tumor; >95% of the tumor was cystic or hyalinized. The stroma varied from being minimal to occasionally prominent myxoid to hyalinized and rarely with organized amianthoid fibers or well-defined smooth muscle bundles. Pathologic stage was reliably assigned in 60 cases, of which 93.3% (56 cases) were pT1, 3.3% (2 cases) were pT2, and 3.3% (2 cases) were pT3a with extension into the perinephric fat. One case had coagulative necrosis; sarcomatoid change and vascular invasion was not identified. The tumors showed a fairly typical immunoprofile characterized by positivity for CK7 (100%), HMCK (96%), CAIX (94%), and vimentin (100%) with negativity for AMACR, RCC, and TFE3; CD10 was positive in 24%. None of the cases tested showed recurrent chromosomal imbalances by virtual karyotyping, fluorescence in situ hybridization, or 3p loss of heterozygosity analysis. VHL gene mutations were, however, noted in 3 cases (2 in exon 1 and 1 in exon 3). Clinical follow-up information was available in 47% of the patients, with a mean and median follow-up of 47 and 37 months, respectively (range, 18 to 108 mo). One case occurred in the setting of VHL syndrome and multiple benign cysts. None of the cases showed local recurrence, metastasis, or death due to disease. Morphology, immunophenotype, and molecular studies did not vary between typical cases, those with prominent smooth muscle (so-called RAT), and historically published data on cases occurring in ESRD. Our analysis confirms that CC-Pap RCC is a unique subtype of adult renal epithelial neoplasia in which tumors are frequently small, are of low nuclear grade and pathologic stage, and have extremely favorable short to intermediate range prognosis. Tumors occurring sporadically, with prominent smooth muscle stroma (so-called RAT), and occurring in ESRD are in the spectrum of the same category of tumors.

Renal cell carcinoma with angioleiomyoma-like stroma: clinicopathological, immunohistochemical, and molecular features supporting classification as a distinct entity

Rare renal epithelial neoplasms have been recognized to have an angioleiomyoma or leiomyoma-like proliferation of stromal smooth muscle; however, the nature of these tumors and their relationships to other renal cell carcinomas are poorly understood. We analyzed 23 such tumors for their clinicopathological, immunohistochemical, and cytogenetic features using fluorescence in situ hybridization. Twelve showed a homogeneous combination of features and were reclassified as renal cell carcinoma with angioleiomyoma-like stroma. These were composed of neoplastic glandular structures lined by cells with mixed clear, pale, and eosinophilic cytoplasm forming occasional papillary tufts. The stroma resembled smooth muscle and often extended away from the epithelial component, entrapping perinephric fat or non-neoplastic renal elements. Immunohistochemistry showed the epithelium to have reactivity for: carbonic anhydrase IX, CD10, vimentin, cytokeratin 7, cytokeratin 34βE12, and PAX8 but not α-methylacyl-coA-racemase. The stroma labeled for smooth muscle (smooth muscle actin 3+, desmin 1+, caldesmon 3+) but not epithelial antigens. Neither component showed substantial reactivity for HMB45, melan-A, cathepsin K, or TFE3 protein. An interrupted, conspicuous layer of CD34-positive endothelial cells rimmed the epithelium, imparting a two-cell layer pattern resembling myoepithelial or basal cells. Chromosome 3p deletion and trisomy 7 and 17 were uniformly absent. Follow-up was available for three patients, none of whom experienced malignant behavior. Eleven tumors were excluded from this category and considered to be clear cell renal cell carcinoma with a reactive proliferation of smooth muscle (n=4) or tangential sectioning of the pseudocapsule (n=2), renal cell carcinoma unclassified (n=4), or clear cell papillary renal cell carcinoma (n=1). In summary, renal cell carcinoma with angioleiomyoma-like stroma is a distinct neoplasm with characteristic morphological, immunohistochemical, and molecular features, unrelated to clear cell renal cell carcinoma. The immunoprofile overlaps partly with that of clear cell papillary renal cell carcinoma, though morphology and reactivity for CD10 are points of contrast.

Clear cell papillary renal cell carcinoma: Incidence, morphological features, immunohistochemical profile, and biologic behavior: A single institution study

This study was undertaken to determine the incidence and the clinicopathologic characteristics of those tumors that qualify as clear cell papillary renal cell carcinoma (CCPRCC) by the current definitions. From January 1, 2003 to April 30, 2013, a total of twenty-eight CCPRCC were identified (28/648, 4.3%). CCPRCC showed variable architectural patterns including cystic, papillary, tubular, and acinar. Irrespective of the architecture, the tumors were composed of cuboidal or columnar cells with clear cytoplasm, small vesicular, round or oval nuclei, and inconspicuous nucleoli. Variably thick bundles of smooth muscle actin-positive soft tissue encircled the whole tumors, forming a continuous pseudocapsule. CCPRCC strongly expressed PAX8, CA-IX, CK7, cytokeratin 34betaE12, and vimentin, and were negative for RCC, P504s/AMACR, and TFE3. On ultrastructural examination, CCPRCC showed short microvilli, cytoplasmic interdigitations, nuclear pseudoinclusions, and stromal myofibroblasts. To the best of our knowledge, this is first comprehensive ultrastructural study of CCPRCC in the literature. The major differential diagnostic considerations are clear cell renal cell carcinoma, multilocular cystic renal cell carcinoma, papillary renal cell carcinoma with clear cell changes, and Xp11.2 translocation renal cell carcinoma. CCPRCC seems to have a favorable prognosis. In the current series, none of the patients had local recurrence or metastatic disease.