Inverted urothelial papillomas with foamy or vacuolated cytoplasm.

Inverted papillomas of the bladder are uncommon benign neoplasms characterized by endophytic growth of urothelial cells as anastomosing cords, displaying minimal cytologic atypia. Reports of inverted papilloma associated with urothelial carcinoma or urothelial carcinoma arising within inverted papilloma highlight the difficulties in evaluating urothelial lesions with inverted growth patterns. Within the spectrum of findings in inverted papilloma, vacuolization and foamy (xanthomatous-appearing) cytoplasmic changes have not been previously reported. In the current study, we present 5 novel cases of inverted papilloma involving 2 men and 3 women ranging in age from 48 to 88 years, who presented with microhematuria (n = 3) or irritative symptoms (n = 2). Cystoscopically, the lesions were polypoid (n = 3), pedunculated (n = 1), or solid (n = 1), measured between 0.7 and 2.5 cm, and were all located at the trigone or bladder neck. Morphologically, all cases had some component of usual inverted papilloma along with areas displaying foamy or vacuolated cytoplasm encompassing 30% to 90% of the lesion. These "clear cells" were seen both in distinct regions within the biopsy and, more frequently, intermingled with usual inverted papilloma cells. In 3 of 5 cases, these findings were sufficiently unusual to cause confusion with urothelial carcinoma. The diagnostic dilemma encountered in these cases of inverted papilloma with foamy or vacuolated cytoplasm warrants their distinction from other benign and malignant urothelial lesions with inverted growth and/or clear cell features.

[Ultrastructural pathologic research on the adult laryngeal papilloma].

In this paper, the ultrastructural features of laryngeal papillomas of 9 cases of adult patients were investigated by means of SEM. It showed that the polypoid surface of the papilloma is easily recognized; the surface cells are covered by microvilli of different size and shape; and the epithelium is bordered by an irregular and continuous basement membrane. In some areas, there is pseudopodium of basal cells stretching into connective tissue. The structure of interface between basement membrane and connective tissue varies with aggravation of tumor cell atypia. The significant variation of structural of basement membrane and semidesmosomes suggests the possibility of malignant change.

Inverted ductal papilloma of minor salivary gland origin: morphological aspects and cytokeratin expression.

Ultrastructural features and cytokeratin expression of inverted ductal papillomas of minor salivary gland origin were studied. Under the electron microscope, an increased number of desmosomes and mucus-like granules in some cells were the most striking features. Immunohistochemical study revealed that tumor cells displayed strongly positive reactions with cytokeratins 13 and 14, and less strong reactions with cytokeratins 7, 8, 18 and 5D3. These results support the hypothesis that an inverted ductal papilloma can be derived from the proximal portion of a salivary gland excretory duct.

Detection of human papillomavirus type 57 in a case of inverted nasal papillomatosis in Japan.

Human papillomavirus (HPV) type 57 DNA was detected in recurrent nasal inverted papillomatosis, in a 60-year-old Japanese male, using Southern blot hybridization. HPV types 6, 11, 16 and 18 were not detectable in the papilloma. Previous studies have shown that HPV types 6, 11, 16 and 18 were mainly found in nasal papillomatosis in other laboratories but the actual detection rate of virus was low. We speculate that this low detection rate may be due to the lack of a method for detecting HPV type 57.

[Ultrastructural characteristics of mast cells and eosinophils in nasal inverted papilloma].

We previously found that an increased number of mast cells and eosinophils accumulated in nasal inverted papilloma and in the nasal mucosa of allergic subjects. Two subtypes of mast cells, i.e., mucosal mast cells and connective tissue mast cells are known to be present in the allergic nasal mucosa. Eosinophils in the allergic nasal mucosa are also heterogeneous. In addition, we demonstrated accumulation of formalin-sensitive mast cells at the tumor site of nasal inverted papilloma. The morphological characteristics and function of mast cells and eosinophils, however, have not yet been identified. The purpose of this study was to determine the ultrastructural characteristics of mast cells and eosinophils in relation to their function in tumor tissue. The results revealed two subtypes of mast cells in nasal inverted papilloma, one distributed mainly in the tumor site, the other mainly in the stromal site. These two subtypes of mast cells had different ultrastructural characteristics. In contrast to stromal mast cells, mast cells in the tumor site were characterized by a smaller cell diameter, fewer specific granules and a higher rate of degranulation. This suggested that they may have played some role in the pathogenesis of the tumor, however, their precise function is still unknown. In comparison with the mast cells in the allergic nasal mucosa, previously reported by Okuda et al, the mast cells in the tumor site were similar to those in the epithelial layer of the allergic nasal mucosa (MMCs), while mast cells in the stromal site resembled those in the lamina propria (CTMCs). There were no marked morphological differences between eosinophils in the tumor site and the stromal site.(ABSTRACT TRUNCATED AT 250 WORDS)