Chromogranin A (LK2H10)

Immunohistochemical methods have localized chromogranin in a wide variety of endocrine tissues including the pituitary, pancreas, hypothalamus, thymus, thyroid, intestine, and parathyroid. Neuroendocrine cells exhibit a fine granular immunoreactivity to chromogranin. It is generally accepted that the co-expression of certain keratins and chromogranin mean neuroendocrine lineage. The presence of strong chromogranin staining and absence of keratin staining should raise the possibility of paraganglioma. The co-expression of chromogranin and NSE is typical of neuroendocrine neoplasms. Most pituitary adenomas and prolactinomas readily express chromogranin.