Chromogranin A
Specificity: A 48-75 kDa acid calcium-binding glycoprotein.
Staining characteristics: Granular cytoplasmic.
Function: One of a family of acid calcium-binding glycoproteins closely associated with neurosecretory granules in virtually all neurons and neuroendocrine cells. Diagnostically, chromogranin A is the most important of that glycoprotein family. Probably the major target of the argyrophilic Grimelius staining reaction. Post-translational processing creates biologically active fragments with autocrine and paracrine functions.
Normal cell distribution: Virtually all neurons and neuroendocrine cells.
Chromogranin A+: Most neural and epithelial neuroendocrine tumors.
- Pituitary adenoma
- Parathyroid tumors
- Pancreatic islet cell tumors
- Medullary thyroid carcinoma
- Carcinoid tumors of the foregut (NOT hindgut)
- Small cell carcinoma
- Merkel cell carcinoma
- Some multiphenotypic tumors such as malignant rhabdoid and desmoplastic small round cell
- Ganglioneuroblastoma
- Ganglioneuroma
- Ganglioglioma
- Phaeochromocytoma
- Sympathetic Paraganglioma and some parasympathetic
- Some oligodendrogliomas
Chromograning A-:
- Carcinoid tumors of the hindgut (NOT foregut)
- Most glial tumors
- Meningioma
- Choroid plexus tumours
- Schwannoma
- Malignant melanoma
- Adrenocortical tumours
- Other carcinomas
- Mesothelioma
- Sarcomas
((()))