1/10. Detection of the ETV6-NTRK3 chimeric rna of infantile fibrosarcoma/cellular congenital mesoblastic nephroma in paraffin-embedded tissue: application to challenging pediatric renal stromal tumors.We report the development of a reverse transcriptase polymerase chain reaction assay that reliably detects the ETV6-NTRK3 chimeric rna characteristic of infantile fibrosarcoma and the cellular variant of congenital mesoblastic nephroma (CMN) in formalin-fixed, paraffin-embedded tissue blocks. The 188 base pair polymerase chain reaction fusion product was detected in 11 of 12 cases of cellular CMN from which a larger sized control rna band could be amplified, and even in 7 of 8 cases in which the control band was not detectable. A variety of other tumors that are in the histologic differential diagnosis of cellular CMN yielded negative results, including four classic CMNs, four rhabdoid tumors of the kidney, and four clear cell sarcomas of the kidney, confirming the assay's specificity. We further demonstrate the assay's utility by illustrating two cases of molecularly confirmed cellular CMN that mimicked rhabdoid tumor and clear cell sarcoma of the kidney. In contrast to previous reports, five mixed CMNs that had both classic and cellular areas all lacked the ETV6-NTRK3 fusion transcript. These results suggest that cases morphologically defined as mixed CMN may represent a mixed group of genetically distinct entities.- - - - - - - - - - ranking = 1keywords = stromal (Clic here for more details about this article) |
2/10. 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.- - - - - - - - - - ranking = 0.25keywords = stromal (Clic here for more details about this article) |
3/10. adult mesoblastic nephroma with ciliated epithelium. A case report.A case of renal pelvic tumors occurring in a 44-year-old man is reported. There were two polypoid renal pelvic tumors which consisted of glandular and stromal components. Some glands in the tumors had ciliated epithelium and were quite similar to the epididymal tubules. Other glands in the tumors resembled the collecting duct or the mesonephric remnant seen in female genitalia. immunohistochemistry and electron microscopy revealed smooth muscle differentiation of the stromal cells of these tumors. Some psammoma bodies were seen in the glands of the tumors. We diagnosed these tumors as adult mesoblastic nephroma (MN). The patient has been followed up for 14 months, showing no evidence of recurrence. Differentiation of the tumors from angiomyolipoma, leiomyoma, and nephrogenic adenofibroma is discussed. adult renal tumors that consist of epithelial and stromal components have been reported under various names. They constitute clinicopathologically different entities originating from pediatric MN. We suggest that these tumors should be termed "adult MN".- - - - - - - - - - ranking = 0.75keywords = stromal (Clic here for more details about this article) |
4/10. Aspiration cytology of mesoblastic nephroma in an adult: diagnostic dilemma.A case of adult mesoblastic nephroma (MN) was erroneously interpreted as a benign mesenchymal tumor on fine-needle aspiration (FNA) cytology. MN is a rare tumor in infants and is extremely uncommon in adults. A 50-yr-old female presented with a renal lump with the clinicoradiological possibility of renal-cell carcinoma. Giemsa-stained smears were highly cellular and showed cohesive interlacing fragments of spindle cells embedded in abundant pink fibrillary stromal matrix. Epithelial component was seen in the form of tubules. Pleomorphism, mitosis, and necrosis were absent. Cytologic features in both adult and infantile MN are similar, but in an adult can be mistaken for benign or malignant mesenchymal tumor and the sarcomatoid variant of renal-cell carcinoma. FNA in such a rare yet cytomorphologically characteristic lesion can be helpful in guiding the management. awareness on the part of both the clinician and the cytopathologist is necessary to resolve the diagnostic dilemma.- - - - - - - - - - ranking = 0.25keywords = stromal (Clic here for more details about this article) |
5/10. Metanephric stromal tumor: a rare benign pediatric renal mass.We report a rare case and description of a benign pediatric renal mass. To our knowledge, this tumor has never been described in urologic published reports. It is possible that the identification of this renal tumor could spare a child the toxic adjuvant chemotherapy that would be administered if confused with histologically similar tumors such as clear cell sarcoma of the kidney.- - - - - - - - - - ranking = 1keywords = stromal (Clic here for more details about this article) |
6/10. Myoid differentiation in mesoblastic nephroma: clinicopathologic and cytogenetic findings of a rare case.The authors report the case of a benign renal mesenchymal tumor in a baby boy detected by ultrasound scanning during prenatal diagnosis. Histologically, the tumor was diagnosed as a congenital mesoblastic nephroma (CMN) with myoid differentiation. The tumor normally is characterized by a fascicular proliferation of bland, spindle-shaped cells. CMN is the most common renal tumor in the neonatal period and presumedly results from a neoplastic transformation affecting the pluripotent mesodermal nephric blastema. In embryonic life, tumorigenic influences acting on the nephric blastema might result in selective overgrowth of its mesoblastic derivates. CMN must be differentiated from other spindle-shaped tumors, like Wilms' tumor, rhabdoid tumor of the kidney, clear cell sarcoma, nephrogenic adenofibroma, fibroma and fibrosarcoma, leiomyoma, metanephric stromal tumor, and, in this case especially, from tumors with myoid differentiation like infantile myofibromatosis. Numerical molecular abnormalities are observed frequently in renal mesenchymal tumors, especially in chromosome 11. Cytogenetic findings in our tumor after comparative genomic hybridization (CGH) showed full trisomies of chromosomes 20 and 22q, partial trisomies for the distal part of 11q and 1p, and an approximately full monosomy of chromosome 4 (4qter-4p15). The chromosomal imbalances of the tumor can be described as: rev ish enh(1p31pter,11q23qter,20,22), dim(4)(p15qter).- - - - - - - - - - ranking = 0.25keywords = stromal (Clic here for more details about this article) |
7/10. Benign mixed epithelial and stromal tumor of the kidney.A 51-year-old, perimenopausal, female patient with 1-month history of right flank pain who was diagnosed with a renal mass and underwent nephron-sparing partial nephrectomy is presented. The renal mass was found to be a benign, biphasic tumor composed of an epithelial component, consisting of ducts of variable size scattered within a mesenchymal component, composed of spindle cells arranged in sheets and fascicles. No atypia, mitosis, or necrosis was found. The spindle component shows desmin, smooth muscle actin, and estrogen and progesterone receptor positivity immunohistochemically. The diagnosis of benign mixed epithelial and stromal tumor of the kidney is rendered. No recurrent disease has been detected during 2 years of follow up.- - - - - - - - - - ranking = 1.25keywords = stromal (Clic here for more details about this article) |
8/10. insulin-like growth factor ii gene expression by congenital mesoblastic nephroma.We studied the expression of insulin-like growth factor ii (IGF2) and Wilms' tumor gene (WT1) in nine cases of congenital mesoblastic nephroma (CMN) and five cases of first trimester fetal kidneys by in situ hybridization. Our aim was to determine their site of expression and to correlate their histogenetic relationship to those of other childhood renal tumors. Our results showed that all nine cases of CMN (classic, mixed, and cellular) contained abundant IGF2 but not WT1 transcripts. The IGF2 transcripts were diffusely distributed over the tumor cells. These findings suggest that CMN is derived from primitive mesenchymal nephrogenic cells and have a potential to differentiate into a stromal cell lineage.- - - - - - - - - - ranking = 0.25keywords = stromal (Clic here for more details about this article) |
9/10. adult mesoblastic nephroma: expansion of the morphologic spectrum and review of literature.Mesoblastic nephroma (MN) is a distinctive tumor that is seen mostly in early infancy and that consists of classic and cellular (atypical) variants. Mesoblastic nephroma rarely occurs in adulthood, but MN in this age group still is poorly characterized because there are only 17 reported cases. We describe five additional cases of adult MN, including one case of the cellular variant, characterize the immunohistochemical profiles in detail, and critically review the previously reported cases. The collective data obtained from these 22 cases of adult MN showed that the patients predominantly were women (20 cases), ranging in age from 19 to 78 years, who were asymptomatic (5 cases) or had nonspecific signs and symptoms referable to a renal mass. Twenty tumors were classified as classic and 2 as cellular. The tumors were 2-24 cm, well circumscribed, and partially encapsulated and displayed a solid/ cystic cut surface, with a predominantly solid component in most tumors. One tumor, however, was almost purely cystic. Most tumors extended to the renal sinus. and some appeared entirely intrapelvic on imaging studies; however, gross and microscopic evaluation did not show destructive invasion of the pelvic wall. Extension of the tumor beyond the renal capsule has not been described. Each tumor was composed of epithelial and stromal components both. The epithelial component, which displayed no difference between the classic and cellular variants, was composed of isolated or clustered tubules and cysts lined by a benign epithelium with a wide range of cytologic differentiation. The stromal cells were composed of fibroblasts, myofibroblasts, and smooth muscle cells in various combinations. Stromal cellularity was low for the classic variant but high for the cellular variant. hemorrhage, necrosis, and high mitotic index were noted in the stroma of the cellular, but not in the classic variant. Immunohistochemical study applied to the five current cases and seven normal control kidneys confirmed the presence of fibroblasts, myofibroblasts, smooth muscle cells, and prominent vessels in the stroma of each tumor. Most cysts and tubules within the tumors had a distinctive immunohistochemical profile, similar to that of collecting duct but different from those of other portions of the nephron in the normal control kidneys. After total or partial nephrectomy, without adjuvant chemotherapy or radiotherapy, 19 patients, including the 2 with cellular MN, were alive and well at 8-months to 48-years follow-up. Follow-up was not available in two patients. The remaining patient had recurrence at the surgical site 24 years after nephrectomy. adult MN displays a distinctive morphologic spectrum that parallels that of its pediatric congener. It probably is a benign tumor that can be treated successfully by complete excision. The collecting duct differentiation expressed by most tubules and cysts of adult MN implies ureteric bud, which is the exclusive embryologic origin of collecting duct, as an important element in the histogenesis of this rare but fascinating type of tumor.- - - - - - - - - - ranking = 0.5keywords = stromal (Clic here for more details about this article) |
10/10. Benign mixed epithelial and stromal tumor of the kidney.We describe a distinctive benign tumor of the kidney in a 48-year-old woman, which was composed of well differentiated ducts set in the spindle cell stroma which was muscle actin, smooth muscle actin and desmin positive, and was morphologically similar to the ovarian stroma. No immature appearing epithelial renal or mesenchymal tissue was present in the tumor. Histologically, the tumor differed from the nephrogenic adenofibroma and the rare cases of adult Wilms tumors, mesoblastic nephromas and cystic nephromas.- - - - - - - - - - ranking = 1keywords = stromal (Clic here for more details about this article) |
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