Histopathology of Esophageal Carcinoma

Preneoplastic and neoplastic epithelial tumors are relatively common and important lesions of the esophagus. Barret’s esophagus, an important risk factor for adenocarcinoma, is divided mainly in three groups (negative for dysplasia, indefinite for dysplasia, and with dysplasia). If neoplastic cells infiltrate the lamina propria or there are atypical glands having architectural atypia the lesion is regarded as an intramucosal carcinoma. Most adenocarcinomas develop in the background of Barret’s mucosa are usually detected at advances stages as ulcerated and infiltrative lesions. Tumors may have a predominant intraluminal growth or they may have a diffusely infiltrative character. Microscopic growth patterns are tubulo-papillary, mucinous, and signet ring cell infiltration. Tumor stage and tumor regression after neoadjuvant chemotherapy are important prognostic parameters. Esophageal squamous dysplasia in which neoplastic changes without invasion are found in the squamous epithelium, usually presents itself as a small, superficial, erythematous area or as a flat or nodular lesion. Esophageal squamous carcinoma is mostly located in the middle third of the esophagus. Superficial cases are plaque-like, polypoid, depressed, or occult while advanced cases are exophytic, ulcerated or infiltrative. Nuclear atypia, abnormal maturation, and keratinization usually help the diagnosis. Besides NOS, rare subtypes as verrucous, spindle cell, or basaloid squamous cell carcinoma can be detected. Reactive conditions, chemoradiotherapy effect, metastatic lesions, and other malignancies should be considered in differential diagnosis. Mucoepidermoid carcinoma is a rare esophageal neoplasm that is composed of an admixture of malignant epidermoid, intermediate, and mucous cells. Adenoid cystic carcinoma of the esophagus is also a rare malignant epithelial tumor with a characteristic cribriform pattern that consists of epithelial and myoepithelial cells. Esophageal neuroendocrine neoplasias are mainly classified into two groups as “well-differentiated neuroendocrine tumors” and “neuroendocrine carcinomas”. In grading systems, mitotic index and Ki-67 proliferation activity are used. Tumors have characteristic neuroendocrine features which should be verified by immunohistochemistry.