Severe Virilization in a Girl With the Homozygous G200SNicotinamide Nucleotide Transhydrogenase Mutation Is Surprisingly Caused by Rare Bilateral Para-Overian Adrenal Rest Tumors

Abstract

Background: Patients with NNT (Nicotinamide Nucleotide Transhydrogenase) gene mutations, a rare cause of glucocorticoid and mineralocorticoid deficiency require hormone replacement therapy. Adrenal Rest Tumor (ART) in females is very rare (<20 cases world-wide) and was reported only in noncompliant patients with congenital adrenal hyperplasia having extremely elevated ACTH levels. This study characterizes the clinical characteristics, the pathophysiology and the molecular ontogeny of a unique ART in a female with adrenal failure due to the G200S mutation in NNT. Clinical presentation and Method: A 15-year-old girl, with homozygous G200S NNT-mutation that caused adrenal insufficiency reappeared to follow-up after several years with severe virilization and elevated serum testosterone (28.3 nmol/l) and ACTH (> 1500 pmol/l) levels. Pelvic MRI and Ultrasound demonstrated one sided para-ovarian 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 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 corticotroph marker-ACTH. The staining for ovarian characteristic markers such as PAX 8 was negative. Studying mRNA extracted from the tissue by RT-PCR revealed the presence of CYP17A1, CYP21A2 and MC2R (ACTH receptor) cDNA confirming typical adrenocortical transcriptional pattern in the tissue. cDNA of POMC was not detected suggesting that in spite of dense ACTH staining the tissue is not classically originated from pituitary corticotrophs. Methylome studies to further characterise the tissue are underway. Conclusion: This study exemplifies severe virilization that resulted from a unique and rare type of ART in ovarian related tissue that was caused by incompliance to treatment in a patient with NNT gene mutation. Given the ubiquitous expression of NNT and its reported pathophysiology as free radicals scavenger in all adrenocortical layers, it is surprising to have high ACTH induced severe virilization in spite of severe NNT dysfunction and adrenal insufficiency. This study may indicate timely testosterone screening in females with NNT mutation and when increased they should probably be laparoscopically surveyed for ART even when not detected by imaging. How NNT mutation damages mineralo and glucocorticoid secreting cells while androgen secreting cells are rescued is a theme for further studies.