Macroadenoma biochemical behavior in pediatric patients with Cushing's disease differs from adult cases
NASHVILLE, Tenn. — Cushing’s disease in children is associated with similar biochemical measures whether the disease is due to macroadenomas or microadenomas, according to a presentation at the AACE 24th Annual Scientific & Clinical Congress.
This contrasts with the disease behavior in adults, in whom macrodenomas demonstrate less glucocorticoid suppression and adrenocorticotropic hormone (ACTH) response to laboratory tests than do microadenomas, according to researchers.
“Children with pituitary macroadenomas are more likely to have the classical response to Cushing's disease functional testing as microadenomas,” Ricardo Correa, MD, a clinical and research endocrinology fellow at National Institutes of Health, told Endocrine Today.
Correa and colleagues conducted a retrospective review of patients with Cushing’s disease who were younger than 18 years when they were admitted to the NIH between 1997 and 2014. All Cushing’s diagnoses were confirmed by pathology.
Pituitary macroadenoma was identified in 13 patients (69% female) and microadenoma in 74 (58% female). The groups had similar mean age (14 years) and BMI (31.8 kg/m2 and 30.2 kg/m2 for macroadenoma and microadenoma, respectively). The macroadenoma group had a median (25% to 75%) 24-hour urine free cortisol of 263.60 mcg/24 hr (range 170.7-528) compared with 371.6 mcg/ 24 hr (range 244.2-625.3) in the microadenoma group (P = 0.47). Median 24-hr urinary 17-hydroxysteroid excretion in the macroadenoma group was 12.6 mg/24 hr (range 8.9-42.5) and 31.6 mg/24 hr (range 4.3-39.9) in the microadenoma group.
Mean morning serum cortisol was 38.9 ± 40.4 mcg/dL compared with 20.2 ± 15.8 mcg/dL in the macroademona and microadenoma groups, respectively (P = 0.16). Mean morning basal plasma ACTH was 106.3 ± 112.3 pg/mL compared with 49.9±44.3 pg/mL for the macroadenoma and microadenoma groups, respectively (P = 0.11), while ACTH responses to the ovine corticotropin-releasing hormone test revealed no statistically significant differences. Using the high dose dexamethasone suppression test, 58% (7/12) suppressed more than 69% in the macroadenoma group compared to 69% (44/64) in the microadenoma group (P = .51).
“Studies in adult patients have demonstrated that macroadenomas have less glucocorticoid suppressibility after the high-dose dexamethasone suppression test and attenuated ACTH response to CRH compared to pituitary microadenomas,” according to Correa. “However, the present study shows that this is not true in children; although patients with macroadenomas had a tendency for higher baseline serum ACTH and cortisol levels, their responses to dynamic testing were similar to those with microadenomas.”
Correa R, et al. Abstract #803. Presented at: AACE 24th Annual Scientific & Clinical Congress; May 13-17, 2015; Nashville, Tenn.
Disclosure: The researchers report no relevant financial disclosures.