Cases reported "Adenoma"

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1/56. Metanephric adenoma of the kidney.

    BACKGROUND: Metanephric adenoma is a rare renal neoplasm that is histologically and clinically unique. We found this neoplasm in a 62-year-old female, whose renal tumor was incidentally detected on abdominal ultrasound examination. methods/RESULTS: Ultrasound, computed tomography and magnetic resonance imaging were compatible with those of renal cell carcinoma. With a diagnosis of renal cell carcinoma, right partial nephrectomy was performed. This tumor showed histologic similarity to developing metanephric tubular epithelium. It was composed of uniformly small epithelial cells, which formed tubules. CONCLUSIONS: The patient has been well and healthy for 20 months after surgery. The unique features of metanephric adenoma should be clinically and pathologically recognized because of its invariably benign course.
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2/56. Metanephric adenoma-like tumors of the kidney: report of 3 malignancies with emphasis on discriminating features.

    BACKGROUND: Metanephric adenoma is a very rare benign renal tumor; only 80 well-documented cases have been reported to date. We have seen several renal tumors that were originally incorrectly diagnosed as metanephric adenoma. DESIGN: We present 3 unusual renal tumors (2 primary and 1 metastatic), each of which illustrates important pathologic features useful in discriminating metanephric adenoma from malignant mimics. RESULTS: Case 1 involved a 46-year-old man with multiple small, cortical, solid, papillary (chromophil) renal cell carcinomas in his right kidney; the patient developed multiple, histologically identical, solid, papillary (chromophil) carcinomas in the opposite kidney 17 months later. Case 2 involved a 32-year-old woman with a 14-cm right renal tumor who developed soft tissue and bone metastases over a 17-year period. Case 3 involved a 52-year-old woman who presented with a 1.8-cm corticomedullary renal nodule, which eventually proved to represent a metastasis from a poorly differentiated (insular) carcinoma of the thyroid. All 3 tumors superficially resembled metanephric adenoma and consisted of primitive, dark-staining cells arranged in tubules or sheets. Each tumor, however, also had features inconsistent with the diagnosis of metanephric adenoma, including multifocal lesions with a variable nuclear-cytoplasmic ratio and diffuse cytokeratin 7 and epithelial membrane antigen immunopositivity in case 1, a 14-cm-diameter tumor with occasional mitoses in case 2, and a distinct fibrous capsule with capsular and vascular invasion in case 3. In addition, all 3 tumors lacked the cytologic features of bland overlapping nuclei with imperceptible cytoplasm consistently seen in metanephric adenoma. CONCLUSION: Adherence to strict histopathologic criteria will discourage misdiagnosis of a malignant or potentially malignant renal neoplasm as the rare and always benign metanephric adenoma.
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3/56. Renal adenomatosis associated with carcinoma of the lower urinary tract: a case report with immunohistochemical study.

    A case of renal adenomatosis of the left kidney associated with a carcinoma of the ipsilateral ureter in a 49-year-old man is examined. One hundred and eight adenomas, which were smaller than 15 mm in diameter, and a single microcarcinoma, which measured 1 mm in diameter, were found in the kidney. Further, there were more than 800 hyperplastic lesions which could be classified into three groups: (i) 792 of distal origin; (ii) 24 of proximal origin; and 10 of collecting duct origin. The serial sections obtained from 19 paraffin blocks were stained using Leu M1 as the proximal marker and epithelial membrane antigen (EMA) as the distal/collecting marker to assist in determining the origins. Ten of the small adenomas (15 lesions), which did not exceed 3 mm in diameter, were predominantly positive for EMA and five were predominantly positive for Leu M1. Further, hyperplastic lesions of distal and collecting duct origins were diffusely positive for EMA and sporadically positive for Leu M1. The lesions of proximal origin were predominantly positive for Leu M1 and sporadically positive for EMA. These findings suggest that a progression from hyperplasia and a direct transition from a single tubule to adenoma occurred multifocally in different segments of the nephrons throughout the left kidney.
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4/56. Metanephric adenoma.

    A 59-year old woman was diagnosed with a tumour in her right kidney. A nephrectomy was performed, and a 45 mm diameter tan-pink coloured tumour was found. microscopy revealed small, dark cells in organized arrays of small round acini and tubules with glomeruloid infoldings. A diagnosis of metanephric adenoma was made. The tumour cells proved diploid on flow cytometry and immunohistochemical staining was positive for CAM 5.2 and AE-3. FISH analysis of three chromosomes did not reveal any abnormal karyotype. It is important to differentiate metanephric adenoma from renal cell carcinoma and adult Wilm's tumour, since it has a benign course.
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5/56. adult mesoblastic nephroma.

    We report a case of asymptomatic mesoblastic nephroma in a 54-year-old woman. The tumor showed immunohistochemical reactions similar to developing nephrons. Electron microscopy showed immature tubules with numerous intracytoplasmic intermediate filaments. Recent studies support the concept of pathogenesis of the mesoblastic nephroma originating from collecting ducts. However, this case exhibited a complex pattern of antigenic expression not restricted to the collecting ducts, but including the glycoprotein CD24 and the neural cell adhesion molecule (NCAM). The following differential diagnoses will be discussed: benign mixed epithelial and stromal tumor, metanephric adenoma, and nephrogenic adenofibroma.
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6/56. Metastatic metanephric adenoma in a child.

    Metanephric adenoma is a recently characterized renal tumor that generally occurs in adults and has an excellent prognosis. To date, only one atypical metanephric adenoma has been reported to metastasize. The authors report a case of typical metanephric adenoma that arose in the left kidney of a 7-year-old girl that was associated with metastases to the para-aortic, hilar, and aortic bifurcation lymph nodes. The tumor was 9.5 cm and was composed entirely of epithelial elements arranged in tubules, short papillae, and glomeruloid bodies with scattered psammoma bodies. No atypia and only rare mitotic activity were present. Immunohistochemically, the tumor was negative for epithelial membrane antigen, negative for keratin AE1, and focally positive for both keratin CAM5.2 and cytokeratin 7. Tumor cytogenetics revealed a normal diploid karyotype, and disomy of chromosomes 7 and 17 was confirmed by fluorescence in situ hybridization. The authors conclude that tumors with histologic, immunohistochemical, and genetic features characteristic of typical metanephric adenoma can present with metastatic disease.
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7/56. Benign renal angiomyoadenomatous tumor: a previously unreported renal tumor.

    We describe a unique benign tumor of the kidney in a 93-year-old man. Microscopically the tumor was composed of an intimate intermixture of epithelial component and smooth muscle tissue, which formed the stroma of the tumor. In some parts the epithelial cells in adenomatous tubular formations were endowed with clear snouts. These clear snouts had a blister-like quality and grew on the secretory cells lining the tubules. No atypias, mitoses, or pleomorphism were present in the tumor. The muscular component consisted of poorly cellular, HMB-45-negative, leiomyomatous bundles, which greatly differed from that of angiomyolipoma. It encircled the whole tumor and intimately intermingled with the epithelial component. These leiomyomatous bands formed focally abortive vessels, which had incomplete and irregular walls and lacked an elastic layer. Even more interesting was a peculiar vascularization of the tumor. All epithelial tubular structures of the tumor revealed an intimate association with small capillaries. A fine labyrinth of the capillaries rimmed the rows of the epithelial cells. To the best of our knowledge this tumor differs from all previously described.
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8/56. adenomatoid tumor of the adrenal gland: a clinicopathologic study of five cases and review of the literature.

    We report the clinicopathologic, immunophenotypic, dna ploidy, and MIB-1 proliferative findings of five adenomatoid tumors of the adrenal gland. All patients were male, and tumors were incidental radiologic, surgical, or autopsy findings. Mean patient age at diagnosis was 41 years (range 31-64 years). The tumors ranged from 1.2 to 3.5 cm (mean 2.8 cm; median 3.2 cm) in greatest dimension, and all originated within the adrenal gland. The tumors were composed of anastomosing variably sized tubules lined by epithelioid as well as flattened cells. Signet-ring-like cells were present in all cases. The previously described histologic patterns of adenomatoid tumor, adenoid, angiomatoid, cystic, and solid, were observed, and each tumor contained multiple histologic patterns. In three of five cases, there was extra-adrenal extension of tumor into periadrenal adipose tissue. All adenomatoid tumors infiltrated the adrenal cortex, and in four cases the adrenal medulla was involved. All tumors exhibited strong immunoreactivity for calretinin, cytokeratins AE1/AE3, and CAM 5.2, cytokeratin 7, and vimentin. Tumors showed weak and focal immunoreactivity for cytokeratin 5/cytokeratin 6 and were negative for CD15, CD31, CD34, cytokeratin 20, MOC31, and polyclonal carcinoembryonic antigen. Ploidy analysis using Feulgen-stained sections and image analysis showed that three tumors were diploid and two were tetraploid. Tumors exhibited low MIB-1 proliferative activity, ranging from 0.2% to 2.7% (mean 1.6%). In three cases with clinical follow-up, no recurrence or metastases occurred. Adrenal gland adenomatoid tumors are morphologically and immunophenotypically identical to adenomatoid tumors of the genital tract and appear benign.
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9/56. Metanephric adenoma.

    In a recent survey of more than one hundred childhood renal tumors in our Laboratory files, we identified a unique case characterized by an unusual degree of differentiation and cell maturity. Histologically this case was notable for an orderly array of small and uniformly-packed tubules with a rosette-like configuration. The nuclei were oval, smooth and of a bland appearance. Mitoses were absent. Many glomerular figures were intermingled. This renal tumor picture is somewhat different from that known as tubular Wilms' tumor because of the well-differentiated adenomatous pattern and the absence of any blastema. The term metanephric adenoma is suggested for this tumor, which may represent the benign counterpart of Wilms' tumor.
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10/56. Nephrogenic adenomas of the urethra involving the prostate gland: a report of two cases of a lesion that may be confused with prostatic adenocarcinoma.

    Two cases of urethral nephrogenic adenoma involving the prostate are described. A diagnosis of prostatic carcinoma was raised in both cases and was seriously entertained in one of them. The patients, who were 65 and 68 yr old, underwent transurethral resection because of difficulty voiding; both had had a prior similar procedure. Microscopic examination in each case showed small tubules and clusters of cells in the fibromuscular stroma of the prostate. In one case the lesional cells had abundant clear cytoplasm, and in both cases some of the nuclei had prominent nucleoli. In each case a minor component of the cystic pattern of nephrogenic adenoma was also present. Features pointing to a diagnosis of nephrogenic adenoma were a morphology that was diagnosis of nephrogenic adenoma were a morphology that was focally characteristic of that lesion, an origin from overlying prostatic urethra in both cases, and negative immunohistochemical staining of the lesional cells for prostate-specific antigen and prostate-specific acid phosphatase. These cases illustrate that nephrogenic adenoma occasionally involves the prostate and in these cases can potentially be confused with prostatic adenocarcinoma.
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