Neuroendocrine Tumors : Mitotic Activity
Evaluating Mitotic Activity in Neuroendocrine Tumors of the GI Tract: Evaluate at least 50 HPFs for mitotic count in the most active areas. Beware of artifacts and mimics of mitotic figures such as pyknotic nuclei, apoptotic bodies, or shrunken nuclei. Due to an element of subjectivity, the interobserver reproducibility of mitotic counts is poor. To address this shortcoming, mitosis-specific markers such as phosphohistone H3 (PHH3) have been evaluated and appear to have high concordance rates with mitotic counts performed with H&E stains. The image shows higher magnification of a well-differentiated neuroendocrine tumor (carcinoid) of rectum discovered incidentally on endoscopy. The cells are uniform and arranged in nests, trabeculae, and cords. The nuclei are round to oval with punctate nucleoli and speckled (salt and pepper) chromatin. There are several rosettes within the nest. Note the eosinophilic cytoplasmic granules in many of the cells, especially around the periphery of the large nest.