Clinically silent corticotroph tumors of the pituitary gland.

OBJECTIVE: To determine the clinical presentation, imaging characteristics, microscopic and ultrastructural characteristics, and treatment outcomes of patients with clinically silent pituitary corticotroph adenomas.

METHODS: All silent corticotroph adenomas diagnosed at the Mayo Clinic during the years 1975 through 1997 were selected from the files of the Mayo Tissue Registry.

RESULTS: We studied 23 cases, occurring in 16 male and 7 female patients (age range, 11-79 yr; mean age, 48 yr), who presented with headaches (50%), visual field defects (61%), extraocular muscle paresis (13%), hypopituitarism (26%), and galactorrhea/amenorrhea (43%/29% of the female patients). No patients exhibited clinical hypercortisolism. All tumors were macroadenomas (2.4+/-0.8 cm; range, 1.5-4.0 cm) and exhibited suprasellar extension in 87% of the cases and hemorrhage, necrosis, and/or cystic changes in 61%. All tumors stained were variably periodic acid-Schiff-, adrenocorticotropic hormone-, and beta-endorphin-positive, particularly Subtype I lesions. Ultrastructural classification was performed in 19 cases. In a comparison of Subtype I and II tumors, differences were observed with respect to sex (male/female, 1.4:1 versus 6:1), preoperative hyperprolactinemia (5 of 16 versus 0 of 6 cases), preoperative hypopituitarism (9 of 16 versus 5 of 7 cases), radiographic or gross invasion (7 of 16 versus 5 of 7 cases), and partial or total postoperative pituitary failure (6 of 16 versus 6 of 6 cases). The overall median postoperative follow-up period was 4.9 years (range, 0.3-16.6 yr); 54% of the patients had persistent or recurrent tumors.

CONCLUSION: Clinically silent corticotroph adenomas behave in an aggressive manner and are characterized by the following: lack of clinical signs or symptoms of Cushing's syndrome and normal cortisol levels; no or only minor elevations of serum adrenocorticotropic hormone levels; macroadenomas with hemorrhagic infarction; and presentation dominated by mass effect symptoms. The high persistence/recurrence rate underscores the need for long-term follow-up.