Endocrine Abstracts

Introduction: Apoplexy of pituitary microadenomas is rare and not well documented in the literature. We aimed to assess the clinical characteristics of apoplexy of pituitary microadenomas compared to that of macroadenomas.

Design: A single-center retrospective longitudinal cohort study.

Methods: We retrieved clinical records of patients over 18 years old, hospitalized in Rambam hospital (Haifa, Israel) between 1.1.2001–31.10.2017, with pituitary apoplexy confirmed by brain imaging (CT or MRI), and with a follow-up of at least one year. We compared clinical and biochemical outcomes of apoplexy among patients with microadenomas and macroadenomas. Statistical analysis was done using Fisher’s exact and Mann-Whitney tests.

Results: We identified 40 patients hospitalized with pituitary apoplexy between 2001–2017. Twenty-seven patients had a follow up of at least one year and were included in the final analysis. Seven (26%) patients had microadenomas, 13 patients (48%) were female. The mean age was 40.7 ± 12.5 years. Patients with microadenomas were younger than those with macroadenomas (29 ± 5 vs 44 ± 12 years, P = 0.006). Median follow-up was 3 and 2.5 years for macro- and microadenoma groups, respectively. Twenty-one patients harbored clinically nonfunctioning pituitary adenomas (6/7 microadenomas and 15/20 macroadenomas). The hormonally functioning tumors were four macroprolactinomas, one microprolactinoma, and one growth hormone-secreting macroadenoma. Upon admission, hyponatremia, random cortisol level of < 200 nmol/l and secondary hypothyroidism, were evident in 6/20, 8/18, and 4/18 patients with macroadenoma and in 1/5, 2/5, and 1/6 patients with microadenoma, respectively (P = NS). Hypogonadotropic hypogonadism was evident in 9/12 men with macroadenoma, but in none of the men with microadenoma. In 12 of macroadenoma patients, the tumor abutted the optic chiasm, of which eight had visual field defects. Fifteen patients with macroadenoma and two patients with microadenoma underwent transsphenoidal surgery within a median of four days. At the last follow-up visit, patients with microadenoma had lower rates of persistent corticotropic deficiency or secondary hypothyroidism compared to patients with macroadenoma (1/7 vs 13/20 respectively, P = 0.033). The rates of persistent corticotropic deficiency or secondary hypothyroidism were comparable between patients that underwent surgery compared to patients that did not (10/17 vs 4/10, respectively, P = NS). 1/7 of patients with microadenoma and 3/20 with macroadenoma had persistent central diabetes insipidus (P = NS). Only 2 patients with macroadenomas had persistent visual field defects at the last follow-up visit.

Discussion: Long term pituitary hormone deficiencies are more common in pituitary apoplexy patients with macroadenomas. Apoplexy of pituitary microadenoma seems to carry a more favorable prognosis.