Nuclear deoxyribonucleic acid content in inverted papilloma of the urothelium

Immunohistochemistry and Fluorescence In Situ Hybridization Can Inform the Differential Diagnosis of Low-Grade Noninvasive Urothelial Carcinoma with an Inverted Growth Pattern and Inverted Urothelial Papilloma

Urothelial carcinoma (UC) comprises a heterogeneous group of epithelial neoplasms with diverse biological behaviors and variable clinical outcomes. Distinguishing UC histological subtypes has become increasingly important because prognoses and therapy can dramatically differ among subtypes. In clinical work, overlapping morphological findings between low-grade noninvasive UC (LGNUC), which exhibits an inverted growth pattern, and inverted urothelial papilloma (IUP) can make subclassification difficult. We propose a combination of immunohistochemistry (IHC) and molecular cytogenetics for subtyping these clinical entities. In our study, tissue microarray immunohistochemical profiles of Ki-67, p53, cytokeratin 20 (CK20) and cyclinD1 were assessed. Molecular genetic alterations such as the gain of chromosomes 3, 7 or 17 or the homozygous loss of 9p21 were also assessed for their usefulness in differentiating these conditions. Based on our analysis, Ki-67 and CK20 may be useful for the differential diagnosis of these two tumor types. Fluorescence in situ hybridization (FISH) can also provide important data in cases in which the malignant nature of an inverted urothelial neoplasm is unclear. LGNUC with an inverted growth pattern that is negative for both Ki-67 and CK20 can be positively detected using FISH.

IS SURVEILLANCE NECESSARY FOR INVERTED PAPILLOMA IN THE URINARY BLADDER AND URETHRA?

BACKGROUND

A case series of inverted papilloma of the urinary bladder and urethra is presented, together with a review of the literature with respect to multiplicity, recurrence rate and association with transitional cell carcinoma, and a discussion on surveillance of the lesion.

METHODS

Cases of inverted papilloma of the lower urinary tract in a single centre were reviewed. Patient and tumour characteristics, recurrence and associated transitional cell carcinoma are reported.

RESULTS

Twenty patients were included (18 male, two female). The mean age was 60.8 years (range 35-78 years). All had solitary tumours ranging from 3 mm to 30 mm in size. Median cystoscopic follow up was 30 months (range 2-140 months). There was no recurrence. One patient was associated with subsequent transitional cell carcinoma 44 and 76 months later. Together with the present 20 cases, review of the English literature with respect to inverted papilloma of the lower urinary tract identified a total of 322 cases reported, with a recurrence rate of 3.85%. Moreover, 1.55%, 5.90% and 1.54% were associated with previous, simultaneous and subsequent transitional cell carcinoma, respectively.

CONCLUSIONS

Recurrence is not uncommon and risk of subsequent transitional cell carcinoma is not rare, such that non-invasive surveillance with flexible cystoscopy is recommended for inverted papilloma of the lower urinary tract.

[Inverted papilloma of the prostatic urethra]

The inverted papilloma is a rare urothelial tumor, and its localization at the prosthatic urethra is also exceptional. We present a case of inverted papilloma of the prostatic urethra in a 72 years-old male, with symptoms of urinary flow obstruction. The diagnose is obtained after urethrocistoscopy and transurethral resection at the same time. We discuss about the etiology, clinical presentation, diagnose and treatment of this rare tumor, making special attention to its malignancy ability.

Inverted urothelial papilloma: is ploidy, MIB-1 proliferative activity, or p53 protein accumulation predictive of urothelial carcinoma?

BACKGROUND

Inverted urothelial papilloma is an unusual neoplasm of the urinary tract. Although the association between inverted urothelial papilloma and urothelial carcinoma is not entirely clear, many studies indicate that patients with inverted papilloma are at increased risk for the development of urothelial carcinoma. In addition, aneuploid inverted papillomas have been associated with the subsequent development of urothelial carcinoma. The objective of this study was to determine whether ploidy, MIB-1 proliferative activity, or p53 protein staining in inverted papilloma were predictive of urothelial carcinoma.

METHODS

Fifty-one cases of inverted papilloma were retrieved from the Tissue Registry of the Mayo Clinic. Clinical records were reviewed for patient age, length of follow-up, and history of urothelial carcinoma (defined as carcinoma prior to, concurrent with, or subsequent to the diagnosis of inverted papilloma). DNA ploidy analysis was determined using Feulgen stained sections from paraffin embedded tissues using an image analysis system. Quantitation of MIB-1 proliferative activity and p53 immunostaining was determined similarly using immunoperoxidase stained sections from paraffin embedded tissues.

RESULTS

The mean age at diagnosis of inverted papilloma was 63.9 years (range, 37-87 years), and there were 39 men and 12 women. Patients were followed for a mean of 56.5 months (range, 1-252 months). Tumors ranged in size from 0.2 to 4.3 cm (mean, 0.9 cm). Eight patients (15.7%) had a prior, concurrent, or subsequent noninvasive World Health Organization and International Society of Urologic Pathology (WHO/ISUP) papillary neoplasm of low malignant potential or papillary carcinoma of low grade (formerly WHO Grade 1 or 2 papillary urothelial carcinoma). Inverted papillomas in patients with a history of urothelial carcinoma were all diploid and had a mean MIB-1 activity of 6.3% (range, 0.04-24.8%) and mean p53 protein staining of 12.6% (range, 0.5-24.9%). These inverted papillomas ranged in size from 0.3 to 1.0 cm (mean, 0.5 cm). Inverted papillomas in patients without a history of urothelial carcinoma were aneuploid in 6 cases (14.3%) and diploid in the remaining cases. These inverted papillomas had a mean MIB-1 activity of 1.6% (range, 0.06-9.0%) and mean p53 protein staining of 9.7% (range, 0.05-38.0%). Tumor size ranged from 0.2 to 4.3 cm (mean, 1.0 cm). There were no statistically significant differences in MIB-1 activity, p53 protein staining, ploidy, and morphologic features between inverted papillomas in patients with and without a history of urothelial carcinoma.

CONCLUSIONS

Ploidy, MIB-1 proliferative activity, and p53 immunostaining in inverted urothelial papilloma were not useful in identifying patients who had a history of urothelial carcinoma.