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Monday, April 2, 2012

Squamous cell carcinoma Histology and Explanation

Squamous cell carcinoma is a malignant epithelial tumor which originates in epidermis, squamous mucosa or areas of squamous metaplasia. In skin, tumor cells destroy the basement membrane and form sheets or compact masses which invade the subjacent connective tissue (dermis). In well differentiated carcinomas, tumor cells are pleomorphic/atypical, but resembling normal keratinocytes from prickle layer (large, polygonal, with abundant eosinophilic (pink) cytoplasm and central nucleus). Their disposal tends to be similar to that of normal epidermis: immature/basal cells at the periphery, becoming more mature to the centre of the tumor masses. Tumor cells transform into keratinized squames and form round nodules with concentric, laminated layers, called "cell nests" or "epithelial/keratinous pearls". The surrounding stroma is reduced and contains inflammatory infiltrate (lymphocytes). Poorly differentiated squamous carcinomas contain more pleomorphic cells and no keratinization. (H&E, ob. x10)Squamous cell carcinoma(skin). Tumor cells transformed into keratinized squames form round nodules with concentric, laminated layers, called "cell nests" or "epithelial/keratinous pearls". 



This is a squamous cell carcinoma arising on the dorsum of the hand. Besides sun exposure, risk factors for squamous cell carcinoma arising inskin include carcinogens such as tars, chronic ulcers, burn scars, arsenicpoisoning, and radiation exposure. In this case there was a history of bothsun exposure as well as exposure to carcinogens


A squamous cell carcinoma is seen at medium power. Note thepleomorphism of the cells. A "squamous eddy" is seen at the upper left,but some of the cells at the right show little keratinization.




A squamous cell carcinoma is shown at high magnification. Many of thecells demonstrate keratinization with abundant pink cytoplasm. Note theprominent cell borders between which can be seen intercellular bridges. Amitosis is seen near the center.

The cells of a basal cell carcinoma are dark blue and oblong with scantcytoplasm. They resemble the cells along the basal layer of normalepidermis





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