Metanephric adenoma

A Case of Metanephric Adenoma and Acute Myocardial Infarction

Metanephric adenoma (MA) is a rare neoplasm that acounts for 0.2% of adult renal neoplasms. MAs are typically discover incidentally during detailed examinations for nonspecific symptoms such as abdominal or flank pain, hematuria, fever and palpable abdominal mass. Additionally, polycythemia has occasionally been reported as well. Herein we describe a case of metanephric adenoma which was an incidental finding in the course of a clinical autopsy in a patient with complete AV block and polycythemia. Histologically, the tumor was composed of small and uniform tubular structures reminiscent of renal tubuli, without signs of cellular atypia and pleomorphism. Such tumor histomorphology was consistent with the diagnosis of metanephric adenoma. Thrombosis is a common complication of polycythemia that often causes death. Polycythemia with an increasing number of blood cells causes hyperviscosity and, in 20-40% of cases, lethal thrombosis or hemorrhage. Hyperviscosity and coronary artery disease in our patient caused acute myocardial infarction with the subsequent rupture of posterior left ventricle wall and hemopericardium.

Metanephric Adenoma of the Kidney with Massive Hemorrhage and Necrosis: Immunohistochemical, Ultrastructural, and Flow Cytometric Studies

Metanephric adenoma of the kidney is rare. We report 2 cases of metanephric adenoma with massive hemorrhage and necrosis. Case 1, a 42-year-old Japanese woman, complained of abdominal pain. Case 2, a 41-year-old Japanese woman, complained of fever and lumbago. They underwent nephrectomy. The cut surface was solid and yellow with massive hemorrhage and necrosis. These tumors showed packed tubular and glomeruloid patterns. The tumor cells were uniform and small, with uniform, oval, and hyperchromatic nuclei and scant cytoplasm, and showed reactivity for cytokeratin, vimentin, and CD 57. The MIB-1 indexes were up to 0.63%. The DNA ploidy pattern was diploid. The tumor cells formed small tubular structures with lumina and microvilli. These features suggested that metanephric adenoma is a benign tumor of an immature epithelial nature.

Laparoscopic nephron-sparing surgery for metanephric adenoma

A 47-year-old patient presented with hematuria of 3-month duration. Computed tomography revealed right lower polar exophytic mass. Laparoscopic nephron-sparing surgery was performed. The macroscopic examination of the mass showed encapsulated tumor with soft pultaceous material. Histologic examination of the mass was consistent with metanephric adenoma. We are reporting this case of metanephric adenoma, being treated with laparoscopic partial nephrectomy.

Application of molecular diagnostic techniques to renal epithelial neoplasms

The application of molecular and cytogenetic techniques to the study of renal neoplasia has resulted in improved understanding of the biologic mechanisms that are responsible for tumor development and progression. It also revealed that several different and specific genetic events are responsible for tumorigenesis in the various categories and subcategories of renal tumors. The ultimate goal of research on the molecular pathology of renal neoplasms is a complete understanding of the genetics of these tumors, which will, in turn, aid in making the correct diagnosis, accurately assessing prognosis, and selecting appropriate and targeted therapeutic options.

Metanephric Adenoma of the Kidney: Case Report and Review of the Literature

Metanephric adenoma is a rare tumor of the kidney. So far metanephric adenomas were considered to be benign, slowly growing and non-metastasizing tumors with an excellent prognosis. Only recently two cases of metastasized metanephric adenomas were published. Therefore, diagnostic work up, therapy and follow up of this tumor have to be reassessed. We report the case of a 42 year old male with metanephric adenoma. Current literature concerning metanephric adenoma is reviewed.

Metanephric adenosarcoma in a young adult: morphologic, immunophenotypic, ultrastructural, and fluorescence in situ hybridization analyses: a case report and review of the literature

Metanephric neoplasms are uncommon renal tumors that arise in both children and adults. They may be composed of small epithelial cells or benign stroma, or both, and are termed metanephric adenoma, metanephric stromal tumor, or metanephric adenofibroma, respectively. Thus far, these tumors have been known for their benign behavior. We present the case of a 21-year-old woman who developed a neoplasm composed of a renal epithelial component identical to metanephric adenoma combined with a malignant spindle cell sarcoma. The epithelial component was positive for pankeratin AE1/3, whereas the sarcomatous component was negative for epithelial markers and positive for vimentin, CD34, and CD117. No smooth muscle differentiation was apparent in the sarcoma by immunohistochemistry or ultrastructural analysis. By fluorescent in situ hybridization analysis of the sarcomatous component there was monosomy of the X chromosome, but no apparent variation from the normal diploid pattern for chromosomes 3, 7, 12, and 17. We conclude that the spectrum of metanephric neoplasia should be expanded to include malignant stromal variants, and we propose the term "metanephric adenosarcoma" for the present case.

Mapping a tumor suppressor gene to chromosome 2p13 in metanephric adenoma by microsatellite allelotyping

Twelve metanephric adenomas (MA) were studied for allelic imbalance at chromosomal regions known to be involved in the genetics of papillary renal cell tumors (RCT) and Wilms' tumors as well as for loci on chromosome 2p13-21. DNA was isolated from paraffin slides, and allelic status was established by fluorescently-labeled microsatellite markers. No allelic changes were seen in the Wilms' tumor gene region at chromosome 11p13 and in the papillary RCT gene region at chromosome 17q21.32. We delineated a tumor suppressor gene region of approximately 8-centimorgan genetic distance between loci D2S2153 and D2S380 on chromosome 2p13. Allelic changes at this region occurred in 56% of informative cases. Our results provide molecular evidence that MA is a genetic entity, and it can be differentiated from both Wilms' tumor and papillary renal cell adenoma.