ESPE Abstracts

Background: Patients with NNT (Nicotinamide Nucleotide Transhydrogenase) gene mutations, a rare cause of glucocorticoid and mineralocorticoid deficiency. Adrenal Rest Tumor (ART) in females, reported so far only in noncompliant patients with congenital adrenal hyperplasia and elevated ACTH levels, is very rare (<20 cases world-wide). This study characterizes the pathophysiology, the molecular ontogeny and methylation analysis of a unique ART in a female with adrenal failure due to the G200S mutation in NNT.

Clinical presentation: A 15-year-old girl, with homozygous G200S NNT-mutation followed for adrenal insufficiency reappeared to follow-up with severe virilization and elevated serum testosterone (28.3 nmol/l) and ACTH (> 1500 pmol/l). Pelvic MRI and Ultrasound demonstrated one sided paraovarian round tumor with pathological vascularization. Laparoscopic exploration revealed bilateral para ovarian mesosalpinx masses involving the serosa of the Fallopian tube, (3 and 1 cm in diameter). The testosterone level normalized within one day after surgical removal of those masses (0.2 nmol/l).

Results: Histopathology demonstrated a pattern of adrenal rest tissue with strong intracellular positive staining for adrenal markers such as SF-1, calretinin, MART1, inhibin and the pituitary marker ACTH. The staining for ovarian marker PAX 8 was negative. Studying mRNA extracted from the tissue by RT-PCR revealed the positive Gene expression of Cyp17a1, Cyp21a2 and Mc2r cDNA but not Pomc suggesting adrenal but not pituitary origin of the tissue. We further profiled the epigenomic profile using the Infinium MethylationEPIC array. Surprisingly, the tumor methylome age was estimated as 40-year-old. The methylation pattern resembled mostly adrenal tissue but was not identical. In part, it expressed unique ovarian methylation pattern.

Conclusion: This study exemplifies severe virilization that resulted from a unique and rare type of ART in ovarian related tissue in a girl with NNT mutation. The laparoscopic surgicalfindings indicate that imaging techniques may be insufficient and call for laparoscopy when clinical findings are suggestive to save fertility. Using histopathology markers cDNA studies and methylation studies, our study shows for the first time that female ART albeit expressing mostly adrenal methylation pattern, is not identical and expresses specific ovarian methylation pattern as well. The growth of a functional androgen producing “tumor” indicates that functional NNT protein is NOT required for androgen synthesis in contrast to glucocorticoids. Identifying the specific methylation pattern, the hypomethylated genes in ART compared to ovarian and adrenal tissue and the reason for its older age as was demonstrated in our research calls for further research.