Pituitary adenoma immunohistochemistry: what to know

After a biopsy or surgery, a pathologist examines the tissue under a microscope. Immunohistochemistry adds selected antibodies that attach to proteins in the cells. The resulting pattern can support a pituitary origin and show whether the cells contain markers linked with hormones such as prolactin, growth hormone, adrenocorticotropic hormone, or other pituitary hormones.

The stain pattern is interpreted with the microscopic appearance, hormone tests, scans, and symptoms. A positive marker is not a diagnosis by itself, and a negative stain does not answer every clinical question. The report may also describe tumour subtype, cell activity, and whether the findings fit the imaging and endocrine assessment.

Ask for the pathology report and have the treating team explain each marker in relation to your blood tests and MRI. Keep a list of medicines and symptoms, especially changes in vision, menstrual periods, sexual function, thirst, urination, headaches, or body features. If tissue is limited or the stains do not match the clinical picture, the team may discuss additional stains or review by a specialist pathologist.

A biopsy is the procedure that provides tissue for laboratory examination; immunohistochemistry is a laboratory method performed on that tissue.

Contact your clinical team promptly for worsening vision, new double vision, severe or rapidly worsening headache, vomiting, confusion, fainting, or unusual sleepiness. After pituitary surgery, follow the discharge instructions for wound concerns, fever, heavy nasal drainage, or marked thirst and frequent urination. These symptoms need clinical assessment regardless of the stain result.

Which markers were tested, and what do they show about the tumour’s cell type? How do the stains fit with my hormone results and MRI? Is the sample adequate, and is specialist pathology review needed? Which symptoms should prompt an urgent call?