The many faces of urothelial carcinoma: an update with an emphasis on recently described variants.

Urothelial carcinoma is well known for its divergent differentiation. Several "variant" morphologies have been described in the literature in recent years and have additionally been recognized in the recent World Health Organization classification of urothelial neoplasms. The importance of recognizing these variant histologies lies in the potential diagnostic, prognostic, or therapeutic implications that accompany these diagnoses. The range of variant morphology seen in the urinary bladder may also be seen in urothelial tumors of the renal pelvis. Herein we review select variants of urothelial carcinoma focusing on the relatively recently recognized variants, outlining the diagnostic features, common differential diagnostic dilemmas, and clinical relevance. This review also includes a discussion on variants on which there is recent information available.

Quantitative characterization of viscoelastic properties of human prostate correlated with histology.

Quantification of mechanical properties of human prostate tissue is important for developing sonoelastography for prostate cancer detection. In this study, we characterized the frequency-dependent complex Young's modulus of normal and cancerous prostate tissues in vitro by using stress relaxation testing and viscoelastic tissue modeling methods. After radical prostatectomy, small cylindrical tissue samples were acquired in the posterior region of each prostate. A total of 17 samples from eight human prostates were obtained and tested. Stress relaxation tests on prostate samples produced repeatable results that fit a viscoelastic Kelvin-Voigt fractional derivative (KVFD) model (r(2)>0.97). For normal (n = 8) and cancerous (n = 9) prostate samples, the average magnitudes of the complex Young's moduli (|E*|) were 15.9 +/- 5.9 kPa and 40.4 +/- 15.7 kPa at 150 Hz, respectively, giving an elastic contrast of 2.6:1. Nine two-sample t-tests indicated that there are significant differences between stiffness of normal and cancerous prostate tissues in the same gland (p < 0.01). This study contributes to the current limited knowledge on the viscoelastic properties of the human prostate, and the inherent elastic contrast produced by cancer.

Congruence of imaging estimators and mechanical measurements of viscoelastic properties of soft tissues.

Biomechanical properties of soft tissues are important for a wide range of medical applications, such as surgical simulation and planning and detection of lesions by elasticity imaging modalities. Currently, the data in the literature is limited and conflicting. Furthermore, to assess the biomechanical properties of living tissue in vivo, reliable imaging-based estimators must be developed and verified. For these reasons, we developed and compared two independent quantitative methods--crawling wave estimator (CRE) and mechanical measurement (MM) for soft tissue characterization. The CRE method images shear wave interference patterns from which the shear wave velocity can be determined and hence the Young's modulus can be obtained. The MM method provides the complex Young's modulus of the soft tissue from which both elastic and viscous behavior can be extracted. This article presents the systematic comparison between these two techniques on the measurement of gelatin phantom, veal liver, thermal-treated veal liver and human prostate. It was observed that the Young's moduli of liver and prostate tissues slightly increase with frequency. The experimental results of the two methods are highly congruent, suggesting CRE and MM methods can be reliably used to investigate viscoelastic properties of other soft tissues, with CRE having the advantages of operating in nearly real time and in situ.

Plasmacytoid urothelial carcinoma: detailed analysis of morphology with clinicopathologic correlation in 17 cases.

The plasmacytoid variant of urothelial carcinoma is rare, of which less than 40 cases have been reported in the English language literature. Herein we report the largest series to date of 17 cases of urothelial carcinoma with plasmacytoid features and report the associated clinicopathologic findings. The architectural pattern of the tumor varied from cells arranged in cords and single cells (35%), small nests (17%), solid sheetlike growth (29%), and diffuse discohesive patternless architecture (23%). The plasmacytoid component varied from 15% to 100% of the specimen analyzed; in 12 cases the plasmacytoid component composed greater than 50% of the tumor. The individual tumor cells had striking morphologic overlap with plasma cells with an eccentrically placed nucleus and abundant amphophilic to eosinophilic cytoplasm. The nuclei were of low to intermediate nuclear grade with minimal nuclear pleomorphism. Thirteen of 17 cases (76%) were associated with conventional high-grade invasive urothelial carcinoma and 9 cases showed very focal intracytoplasmic vacuoles mimicking signet ring cells. One case also showed sarcomatoid dedifferentiation. The tumor cells were positive for cytokeratin 7 (94%) and cytokeratin 20 (31%); CD138 was positive in 94% of cases. All cases were invasive -- 7 into at least the lamina propria, 7 into at least the muscularis propria, and 3 into perivesical fat. Follow-up information was available in 16 cases (range: 2 wk to 43 mo; mean 10 mo; median 5.5 mo). Eleven patients died of disease and 5 patients were alive with disease. Plasmacytoid variant of urothelial carcinoma is an aggressive subtype associated with poor prognosis. In limited samples, it may be misdiagnosed as chronic cystitis or plasmacytoma, a pitfall further compounded by CD138 expression. Distinction from metastatic carcinoma from other primary sites such as stomach and breast is critical due to differing therapeutic implications.

Tissue elasticity properties as biomarkers for prostate cancer.

In this paper we evaluate tissue elasticity as a longstanding but qualitative biomarker for prostate cancer and sonoelastography as an emerging imaging tool for providing qualitative and quantitative measurements of prostate tissue stiffness. A Kelvin-Voigt Fractional Derivative (KVFD) viscoelastic model was used to characterize mechanical stress relaxation data measured from human prostate tissue samples. Mechanical testing results revealed that the viscosity parameter for cancerous prostate tissue is greater than that derived from normal tissue by a factor of approximately 2.4. It was also determined that a significant difference exists between normal and cancerous prostate tissue stiffness (p < 0.01) yielding an average elastic contrast that increases from 2.1 at 0.1 Hz to 2.5 at 150 Hz. Qualitative sonoelastographic results show promise for cancer detection in prostate and may prove to be an effective adjunct imaging technique for biopsy guidance. Elasticity images obtained with quantitative sonoelastography agree with mechanical testing and histological results. Overall, results indicate tissue elasticity is a promising biomarker for prostate cancer.

Prostate cancer: three-dimensional sonoelastography for in vitro detection.

PURPOSE: To prospectively evaluate the accuracy of three-dimensional (3D) sonoelastographic imaging, relative to that of gray-scale ultrasonography (US), in the in vitro detection of prostate cancer. MATERIALS AND METHODS: The study was approved by the institutional review board and was HIPAA compliant. Informed consent was obtained from all patients. Nineteen prostatectomy specimens from patients aged 46-70 years with biopsy-proved prostate cancer were scanned in three dimensions by using conventional B-mode US and sonoelastography with vibrations of more than 100 Hz. Step-sectioned whole-mount histologic specimens were used to create a 3D volume of the prostate and the tumors within it. B-mode US scans and regions of low vibration on the sonoelastographic images (hard regions) were formatted in three dimensions. The lesions in the 19 cases were classified into two groups, as follows: G1 lesions were pathologically confirmed tumors with a volume of at least 1.0 cm3, and G2 lesions were pathologically confirmed tumors smaller than 1.0 cm3. G1 lesions were evaluated with B-mode US and sonoelastography and classified as true-positive, false-positive, true-negative, or false-negative; G2 lesions were evaluated only with sonoelastography. Findings at histologic examination were used as the reference standard. True-positive findings necessitated 3D lesion correlation between pathologic and imaging data. Conventional definitions of accuracy and sensitivity were used for statistical analysis. RESULTS: For G1 lesions (seven lesions with a volume of at least 1.0 cm3), sonoelastography had an accuracy of 55% and a sensitivity of 71% and B-mode US had an accuracy of 17% and a sensitivity of 29%. The mean tumor volume was 3.1 cm3 +/- 2.1 (standard deviation). For G2 lesions (22 lesions with a volume of less than 1.0 cm3), the mean tumor volume was 0.32 cm3 +/- 0.21. Sonoelastography had an accuracy of 34% and a sensitivity of 41%; there were six false-positive findings. CONCLUSION: Sonoelastography performed considerably better than did gray-scale US in the depiction of prostate cancer for tumors with volumes of more than 1 cm3.

Masson's intravascular hemangioma masquerading as effort thrombosis.

An otherwise healthy 55-year-old white woman had acute onset of right arm swelling. No precipitating factors were identified. Venograms revealed an occluded subclavian vein, and catheter-directed thrombolysis was performed. After lysis a persistent residual intraluminal filling defect was identified, with persistent symptoms. Partial claviculectomy was performed, the mass was removed, and patch venoplasty carried out, with good outcome. Pathologic analysis demonstrated the mass to be a Masson's hemangioma, a papillary proliferation of thin-walled capillaries intimately associated with thrombus. Considered a benign intravascular lesion, the treatment of choice is complete excision.