Carcinoid : Nuclear Features
Carcinoid tumor cells are polygonal in shape with a uniform monomorphic appearance and moderate quantity of granular eosinophilic cytoplasm. The nuclei are round or oval with finely dispersed granular chromatin (salt and pepper appearance) and inconspicuous or punctate nucleoli. Occasional foci with highly pleomorphic nuclei (not accompanied by necrosis or increased mitoses), multinucleated cells, or prominent nucleoli may be present. Mitotic activity is low (less than 2 mitoses per 10HPF or 2 sq.mm). Rare cases are composed predominantly of oncocytic or clear cells or may contain abundant melanin.