Unusual MRI finding of multiple adenomas in the pituitary gland: A case report and review of the literature

The simultaneous occurrence of multiple adenomas in the pituitary gland is a rare event, We report the coexistence of three non functioning pituitary microadenomas in a 37-year-old woman, referred to us for oligomenorrhea and headache. Biochemical evaluation revealed prolactin (131 U/liters), follic le-stimulating hormone (4.1 U/liters), luteinizing hormone (3.9 U/liters), 17 beta-estradiol (74 pg/mL), free (2.0 pg/mL) and total testosterone (0.5 ng/mL), dehydroepiandrosterone-sulfate (3.5 mu g/mL), 17OH-progesterone (0. 8 ng/mL), cortisol (13.1 mu g/dL), free triiodothyronine (4.8 pmol/L), free thyroxine (18.5 pmol/liters), thyrotropin (1.6 mU/L), and growth hormone ( 0.2 ng/mL) levels in the normal range, as for as the response to dynamic en docrine tests. MRI showed an enlarged sella turcica, occupied by three dist inct hypointense areas that measured less than 5 mm in diameter in the left , medium and right side of the pituitary, respectively. This finding was co nfirmed 6 months later by a second MRI that revealed also a light increase in microadenomas dimensions. The patient, therefore, underwent neurosurgery by transfenoidal approach. Histologic examination showed no morphologic di fferences between the specimens obtained from the different microadenomas. Immunohistochemistry evaluation revealed a positive staining for the common alpha-subunit of glycoproteic hormones and negative for the other pituitar y hormones tested, while electron microscopy showed cells with a poor secre tory apparatus and a variable grade of cell differentiation. In conclusion, we report the fifth case described with multiple pituitary adenomas diagno sed in vivo and the first with three coexisting tumors revealed by MRI befo re neurosurgery. The occurrence of multiple pituitary tumors emphasizes the role of pituitary and extrahypophiseal factors in the clonal expansion of genetically altered cells. (C) 1999 Elsevier Science Inc.