Prevalence, distribution, and prognostic significance of morphological variants of neuroendocrine tumors of the gastrointestinal tract - a multicenter study.

The incidence and prevalence of neuroendocrine neoplasms (NENs) in many organs are increasing. Although such NENs have similar grades, they may exhibit quite different behaviors. In this multicenter study, we aimed to investigate the prevalence and distribution of different morphological NEN variants in the non-pancreatic gastrointestinal (GI) tract and determine whether they can guide prognosis prediction.

Cytokeratin 17 and Ki-67: Immunohistochemical markers for the differential diagnosis of keratoacanthoma and squamous cell carcinoma.

The clinical and histopathological distinction between keratoacanthoma (KA) and squamous cell carcinoma (SCC) is essential, but frequently difficult to make. The utility of CK17 and Ki-67 expression in distinguishing between KA and SCC was investigated. Immunohistochemical staining patterns for CK17 and Ki-67 were evaluated in 24 KA and 27 SCC cases.

Mucinous urothelial carcinoma of the renal pelvis.

Urothelial carcinoma with abundant myxoid stroma is a newly-described and extremely rare entity. Since only very few cases have been reported, there is no consensus on its nomenclature. Microscopic examination revealed invasive urothelial carcinoma with widespread low-grade noninvasive areas.