Correcting the Shrinkage Effects of Formalin Fixation and Tissue Processing for Renal Tumors: toward Standardization of Pathological Reporting of Tumor Size

Given the importance of correctly staging renal cell carcinomas, specific guidelines should be in place for tumor size measurement. While a standard means of renal tumor measurement has not been established, intuitively, tumor size should be based on fresh measurements. We sought to assess the accuracy of postfixation and microscopic measurements of renal tumor size, as compared to fresh measurements and radiographic size. Thirty-four nephrectomy cases performed by a single surgeon were prospectively measured at different time points. The study cases included 23 clear cell renal cell carcinomas, 6 papillary renal cell carcinomas, and 5 other renal tumors. Radiologic tumors were 12.1% larger in diameter than fresh tumors (P<0.01). Furthermore, fresh specimens were 4.6% larger than formalin-fixed specimens (P<0.01), and postfixation measurements were 7.1% greater than microscopic measurements (P<0.01). The overall mean percentage of shrinkage between fresh and histological specimens was 11.4% (P<0.01). Histological processing would cause a tumor stage shift from pT1b to pT1a for two tumors in this study. The shrinkage effects of formalin fixation and histological processing may result in understaging of renal cell carcinomas. The shrinkage factor should be considered when reporting tumor size

Solitary fibrous tumour of the genitourinary tract: a clinicopathological study of 11 cases and their association with the NAB2-STAT6 fusion gene

Aims To characterise clinicopathological features and clinical outcomes of the genitourinary tract solitary fibrous tumours, incorporating NAB2-STAT6 gene fusion status. Methods The presence of the molecular hallmark NAB2-STAT6 gene fusion and for the defining fusion partner product STAT6 was assessed in 11 cases of the genitourinary tract solitary fibrous tumours. NAB2-STAT6 gene fusion analysis was performed using a break-apart fluorescence in situ hybridisation (FISH) probe using a probe cocktail with Bacterial artificial chromosome (BAC) clones for STAT6 and NAB2. Results Eleven solitary fibrous tumours were diagnosed in eight male patients and three female patients with a mean age of 46 years (range: 11–64 years). Four of the tumours had malignant histological features, and three were considered moderate risk for metastasis. With a mean follow-up time of 61 months, 1 recurred locally and 2 presented at distant metastatic sites. Using a break-apart FISH probe cocktail, we found the NAB2-STAT6 gene fusion and nuclear STAT6 expression in 58% and 91% of cases, respectively. However, the NAB2-STAT6 fusion status was not correlated with STAT6 expression or useful in discriminating between malignant histological features or subsequent clinical outcomes in the genitourinary solitary fibrous tumours. Conclusions A subset of solitary fibrous tumours of the genitourinary tract behaved aggressively. Using a break-apart FISH probe cocktail, we found the NAB2-STAT6 gene fusion in 64% of cases. However, the NAB2-STAT6 fusion status was not correlated with STAT6 expression or useful in discriminating between low-risk or high-risk tumours and subsequent clinical outcomes

Isolated omental duplication cyst with respiratory epithelium & pancreatic glands: Case report & review of literature

Duplication cysts are uncommon congenital anomalies. They are usually in communication with or are attached to an adjacent segment of bowel. Rarely are they completely isolated from the gastrointestinal tract. To date, there have been 29 reported cases of non-communicating or isolated duplication cysts. Few contain respiratory epithelium and pancreatic glands. Patients may present with pain, an acute abdomen, bleeding or malignant degeneration. Differential diagnoses for an isolated cystic mass should include duplication cyst in the pediatric population. Recognition and awareness of these anomalies and their various presentations can aid in management. The unusual case of an isolated duplication cyst containing respiratory and pancreatic tissue, found within omentum, is presented with a review of the literature

Basal cell carcinoma of the prostate is an aggressive tumor with frequent loss of PTEN expression and overexpression of EGFR

Basal cell carcinoma (also referred to as adenoid cystic carcinoma) is a rare tumor of the prostate. Although largely characterized as indolent, poor outcomes have been reported in a considerable fraction of cases. As yet, optimum treatment strategies for this cancer have not been developed. This study investigates protein expression of common or potential molecular therapeutic targets and reports on the clinicopathological features of 9 new cases: We evaluated the expression of ERBB2, KIT, androgen receptor, PTEN, EGFR, ERG, and p53 via immunohistochemistry. We also examined EGFR amplification and TMPRSS2-ERG gene rearrangement by fluorescence in situ hybridization. The mean clinical follow-up was 44 months. We found that basal cell carcinoma behaved aggressively with almost one-half of the cases displaying high-risk pathologic features or local recurrence (44%). One patient died as a result of metastatic disease. The most consistent abnormalities included a loss of PTEN expression (56% of cases) and EGFR overexpression (67% of cases). EGFR overexpression occurred in the absence of gene aniplification. The TMPRSS2-E1G,rearrangement was not detected in any of the tumors studied, nor. was ERG protein positiyity identified by immunostaining. In addition, ERBB2, KIT, p53, and androgen receptor expressions were either absent or showed only weak, limited reactivity. Our results suggest that there is a high morbidity associated with this tumor, and more intense follow-up and additional treatment may be indicated. Furthermore, targeted therapies directed against the EGFR and PTEN proteins or their constitutive pathways may be promising for future clinical management

Basal cell carcinoma of the prostate is an aggressive tumor with frequent loss of PTEN expression and overexpression of EGFR

Basal cell carcinoma (also referred to as adenoid cystic carcinoma) is a rare tumor of the prostate. Although largely characterized as indolent, poor outcomes have been reported in a considerable fraction of cases. As yet, optimum treatment strategies for this cancer have not been developed. This study investigates protein expression of common or potential molecular therapeutic targets and reports on the clinicopathological features of 9 new cases. We evaluated the expression of ERBB2, KIT, androgen receptor, PTEN, EGFR, ERG, and p53 via immunohistochemistry. We also examined EGFR amplification and TMPRSS2-ERG gene rearrangement by fluorescence in situ hybridization. The mean clinical follow-up was 44 months. We found that basal cell carcinoma behaved aggressively with almost one-half of the cases displaying high-risk pathologic features or local recurrence (44%). One patient died as a result of metastatic disease. The most consistent abnormalities included a loss of PTEN expression (56% of cases) and EGFR overexpression (67% of cases). EGFR overexpression occurred in the absence of gene amplification. The TMPRSS2-ERG rearrangement was not detected in any of the tumors studied, nor was ERG protein positivity identified by immunostaining. In addition, ERBB2, KIT, p53, and androgen receptor expressions were either absent or showed only weak, limited reactivity. Our results suggest that there is a high morbidity associated with this tumor, and more intense follow-up and additional treatment may be indicated. Furthermore, targeted therapies directed against the EGFR and PTEN proteins or their constitutive pathways may be promising for future clinical management

Tubulocystic renal cell carcinoma is an entity that is immunohistochemically and genetically distinct from papillary renal cell carcinoma

AIMS: Some studies have suggested that tubulocystic carcinoma may be related to papillary renal cell carcinoma. We sought to compare and contrast the molecular and immunohistochemical profiles of tubulocystic carcinoma with those of papillary renal cell carcinoma. METHODS AND RESULTS: Twelve cases of pure tubulocystic renal cell carcinoma were subjected to fluorescence in-situ hybridization assessment of chromosomal number for chromosomes 7 and 17, and for TFE3 translocation. Immunohistochemical labelling for AMACR, p63, cytokeratin 7, PAX8, cytokeratin 20 and carbonic anhydrase IX was assessed in all tumours. No tumour showed gains of chromosomes 7 or 17, or TFE3 translocation by fluorescence in-situ hybridization. Immunohistochemistry revealed all tumours to be non-reactive with antibodies against p63 and cytokeratin 20. Conversely, the antibody against AMACR gave a positive reaction in the neoplastic cells of all tumours. Four tumours showed focal labelling with antibody against carbonic anhydrase IX, and five tumours showed focally positive reactions with antibody against cytokeratin 7. Recurrence and metastatic disease were not found for the patients with available follow-up information. CONCLUSIONS: Pure tubulocystic renal cell carcinoma is an indolent tumour with a good prognosis. Our data support the distinction of this neoplasm as a separate entity

Tubulocystic renal cell carcinoma is an entity that is immunohistochemically and genetically distinct from papillary renal cell carcinoma

AIMS: Some studies have suggested that tubulocystic carcinoma may be related to papillary renal cell carcinoma. We sought to compare and contrast the molecular and immunohistochemical profiles of tubulocystic carcinoma with those of papillary renal cell carcinoma. METHODS AND RESULTS: Twelve cases of pure tubulocystic renal cell carcinoma were subjected to fluorescence in-situ hybridization assessment of chromosomal number for chromosomes 7 and 17, and for TFE3 translocation. Immunohistochemical labelling for AMACR, p63, cytokeratin 7, PAX8, cytokeratin 20 and carbonic anhydrase IX was assessed in all tumours. No tumour showed gains of chromosomes 7 or 17, or TFE3 translocation by fluorescence in-situ hybridization. Immunohistochemistry revealed all tumours to be non-reactive with antibodies against p63 and cytokeratin 20. Conversely, the antibody against AMACR gave a positive reaction in the neoplastic cells of all tumours. Four tumours showed focal labelling with antibody against carbonic anhydrase IX, and five tumours showed focally positive reactions with antibody against cytokeratin 7. Recurrence and metastatic disease were not found for the patients with available follow-up information. CONCLUSIONS: Pure tubulocystic renal cell carcinoma is an indolent tumour with a good prognosis. Our data support the distinction of this neoplasm as a separate entity