Pituitary macroadenoma - prolactinoma

Case contributed by Royal Melbourne Hospital


Galactorrhea. Otherwise well.

Patient Data

Age: 35 years
Gender: Female

MRI pituitary


MRI of the pitutary including dynamic contrast enhanced sequences demonstrates a 11 x 12 x 9 mm mass in the left pituitary gland. There is remodeling of the sellar floor, which slopes to the left. There is displacement of the infundibulum and normal pituitary tissue to the right. There is slight tilting of the chiasm, but without chiasmal contact. 

While the mass abuts the left cavernous carotid, there are no specific signs for cavernous sinus invasion. 

This patient was treated medically with bromocriptine and followed with pituitary imaging over the next 14 months. Unfortunately she did not respond to medical treatment. 



MICROSCOPIC DESCRIPTION: Paraffin sections show fragments of a moderately hypercellular adenoma.  Tumor cells have uniform round and oval vesicular nuclei and a variable amount of pale cytoplasm and are arranged in prominent trabeculae surrounding thin walled capillaries.  No mitotic figures or areas of necrosis are identified and no normal anterior pituitary tissue is included.  Immunohistochemistry shows weak cytoplasmic staining for prolactin in the majority of tumor cells and strong granular perinuclear staining for CAM5.2 . No staining for growth hormone, ACTH, LH, FSH or TSH is seen in tumor cells. The features are of a sparsely granulated prolactin secreting adenoma. The topoisomerase labeling index is <1%. 

FINAL DIAGNOSIS: Pituitary tumor: Sparsely granulated prolactin secreting adenoma (prolactinoma).

Case Discussion

Prolactinomas make up the majority of pituitary macroadenomas and are fortunately often responsive to medical management. In cases such as this one where the tumor is refractory to medical management, of if there is significant compression of the optic apparatus, then surgical resection is necessary. 

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