The leiomyomatous stroma in renal cell carcinomas is polyclonal and not part of the neoplastic process.

Some renal epithelial neoplasms, such as renal angiomyoadenomatous tumor, clear cell papillary renal cell carcinoma and renal cell carcinoma with smooth muscle stroma, contain a variably prominent smooth muscle stromal component. Whether or not this leiomyomatous stroma is part of the neoplastic proliferation has not been firmly established. We studied the clonality status of 14 renal cell carcinomas with a prominent smooth muscle stromal component (four renal angiomyoadenomatous tumors/clear cell papillary carcinomas, five clear cell carcinomas, two papillary carcinomas, and three renal cell carcinomas with smooth muscle rich stroma) using the human androgen receptor assay (HUMARA). We found the leiomyomatous stromal component in all analyzable (8/14) cases to be polyclonal and therefore reactive rather than neoplastic. Based on morphological observations, we propose that the non-neoplastic leiomyomatous stromal component is likely derived from smooth muscle cells of large caliber veins located at the peripheral capsular region or within the collagenous septae of the tumors.

[Pathohistological changes in fetuses with cystic fibrosis].

INTRODUCTION: Cystic fibrosis or mucoviscidosis is a genetically caused disease. The intensity of disease and histopathological changes grow throughout the life. According to the literature, pathological changes characteristic of cystic fibrosis become noticeable around the sixth month of life. CASE REPORT: After amniocentesis of a 5-lunar month-old fetus had been done, which confirmed cystic fibrosis, the Ethics Commission approved the preterm labor. The autopsy and histopathological analysis demonstrated the existence of typical histopathological changes in the pancreas and intestines. DISCUSSION: In the late fetal period or during the period around the delivery, cystic fibrosis is usually manifested as meconial cap with or without obstruction of the intestinal lumen. Morphological changes in the exocrine glands usually develop only after birth. In this case, the existence of meconial obstruction, as well as the typical acidofil content in the secretory ducts and acini of the pancreas was confirmed, which is unusual for the fetal age of five months.

A distinctive translocation carcinoma of the kidney; "rosette forming," t(6;11), HMB45-positive renal tumor: a histomorphologic, immunohistochemical, ultrastructural, and molecular genetic study of 4 cases.

To date, only a few cases of "rosette forming t(6;11), HMB45-positive renal carcinoma" have been published. In this article, we contribute further data on 4 cases of this rare entity. Patients were 3 women and 1 man with an age range of 20 to 54 years (median, 23 years). Follow-up (range, 3-5 years; median, 4 years) did not reveal any metastatic events or recurrences. All tumors were well circumscribed and mostly encapsulated with homogeneous gray to tan cut surfaces. No necrosis was seen. All tumors displayed a solid or solid/alveolar architecture and contained occasionally long and branching tubular structures composed of discohesive neoplastic cells and pseudorosettes. The presence of pseudorosettes was a constant finding, but the number of pseudorosettes varied significantly among cases. All cases displayed focal immunoreactivity for the melanocytic marker HMB45, cathepsin K, and vimentin. Melan A, tyrosinase, cytokeratins, CD10, and microphthalmia transcription factor were each positive in 3 of 4 cases. On ultrastructural examination, numerous electron-dense secretory cytoplasmic granules with some resemblance to melanosomes were identified. The pseudorosettes were composed of reduplicated basement membrane material surrounded by small lymphocyte-like neoplastic cells. Using reverse transcription polymerase chain reaction, 2 tumors were positive for the Alpha-TFEB fusion transcript. The presence of the translocation t(6;11)(Alpha-TFEB) was confirmed in 2 analyzed cases. No von Hippel-Lindau tumor suppressor gene mutation, promotor methylation or loss of heterozygosity of 3p was found. Losses of part of chromosome 1 and chromosome 22 were found in one case.

Renal small cell oncocytoma with pseudorosettes A histomorphologic, immunohistochemical, and molecular genetic study of 10 cases.

A cohort of a heretofore not described rare subtype of renal oncocytoma, small cell oncocytoma with pseudorosettes is presented. Patients were 6 women and 4 men with ages ranging from 51 to 76 years. The tumors displayed areas composed of small cells ("oncoblasts") featuring scant cytoplasm and small, round monomorphic nuclei. The small cell areas constituted 15% to 60% of the total tumor volume (mean, 28.5%; median, 22.5%). No necrosis or mitotic activity was discerned. All tumors also contained areas composed of characteristic oncocytes comprising 40% to 85% of the total tumor volume. In all cases, a varying number of pseudorosettes were identified. The pseudorosettes were composed of small globules of (periodic acid-Schiff-positive) hyaline basal membrane-like material surrounded by small "oncoblastic" cells. The immunohistochemical profile was variable, including at least focal positivity for AE1-3 (10/10), cytokeratin 7 (7/10), epithelial membrane antigen (10/10), c-kit (6/10), antimitochondrial antigen (MIA;10/10), PAX-2 (9/10), AMACR (racemase;6/10), CD10 (5/10), parvalbumin (8/10), vimentin (6/10), claudin 7 (10/10), and claudin 8 (3/10). No immunoreactivity for carbonic anhydrase 9, HMB-45, S-100A1, and TFE3 was documented. We found no differences in the immunophenotype in the small cell oncocytes/oncoblasts that formed pseudorosettes and those that did not. However, there were differences in the immunohistochemical profile of classic oncocytes and small cell oncocytes/oncoblasts. Using array comparative genomic hybridization, no chromosomal changes were identified in any of the cases examined (n = 3). No numerical changes of chromosomes 7 and 17 were revealed on fluorescence in situ hybridization analysis (n = 3). In conclusion, we herein present the first study on small cell renal oncocytomas with formation of pseudorosettes. This is a rare subtype of oncocytoma, which may, especially on a core biopsy, present differential diagnostic difficulties. The immunohistochemical profile of these tumors is variable and differs in significant respects from that of conventional renal oncocytoma. Awareness of this entity and its immunohistochemical variability should help in distinguishing this rare tumor from malignant tumors with similar (small cell) histomorphologic features. All tumors behaved in a benign fashion during follow-up (mean, 3.1 years; median, 1 year).

Bilateral renal tumors; conventional clear cell carcinoma and contralateral t(6;11)/t(X;17)-like tumor Histomorphologic, immunohistochemical, ultrastructural and molecular genetic studies including the report of a novel mutation in the VHL gene.

A 34-year-old pregnant woman with bilateral kidney tumors 9.5 and 2.5 cm in maximum diameter is presented. The larger tumor was clear renal cell carcinoma. The smaller contralateral tumor was focally HMB45 positive and had unusual histomorphology, including features resembling clear renal cell carcinoma with features of both t(6;11)- and t(X;17)/ASPL-TFE3 carcinomas. This tumor displayed a complex karyotype. A novel germ line mutation in the VHL gene (c.439A>G/p.I147V) was also identified in this patient.

[Morphological parameters of prostatic adenocarcinoma].

INTRODUCTION: Prostatic carcinoma is one of the most common malignancies in men and the second most common cause of cancer-related deaths, after lung cancer. However, many of these tumors are latent, of no biologic significance, and are recognized only as an incidental findig at autopsy. PROSTATIC CARCINOMA: HISTOLOGIC FEATURES: Prostatic carcinomas have multiple histologic patterns, which can easily be confused with benign lesions. The following histologic changes are associated with prostatic carcinomas. prostatic acini are close to one another and present with linear infiltrates in the fibromuscular tissue; cells lining the acini often consist of a single layer, and the basal cell layer is absent; prominent large eosinophilic nucleoli are usually present in malignant cells; nuclear hyperchromatism is rare and it depends on the quality of the tissue fixation; perineural invasion is often observed. Today, the Gleason grading system is the most commonly used (Gleason score). Immunohistochemistry is widely used in pathology and clinical diagnosis of prostatic carcinoma, metastases of prostatic origin in staging malignant tumors and in the prognosis.