Endocrine Abstracts

Background: McCune Albright Syndrome (MAS) is a rare mosaic disease caused by activating mutation in GNAS, characterized by bone fibrous dysplasia, café au- lait (CAL) and hyper functional endocrinopathies (1). GIPP is the most common endocrinologic manifestation seen more frequently in girls (2). In a few studies, letrozole, tamoxifen, or fulvestrant were effective in decreasing the rate of skeletal maturation and vaginal bleeding (3,4,5).

Case Report: A 3-month-old female infant presented with vaginal bleeding for 5 days. On examination she had CAL and firm prominent breast. Investigations were consistent with GIPP. Oestradiol levels was 1552 pmol/l (<44 pmol/l) with undetectable gonadotrophins. Ultrasound showed bilateral ovarian cyst maximum diameter 7 mm. On our initial evaluation, bleeding had self-resolved and oestradiol levels were 828 pmol/l. We decided to wait and watch. At 7 months there was again breast enlargement, Oestradiol levels peaked at 8364 pmol/l. Scans showed reoccurrence of ovarian cysts, the left side larger than the right (56 mm x 49 mm x 35 mm). The uterus was enlarged for age. Tumour markers (AFP/BHCG) were negative. Skeletal survey revealed significantly advanced bone age of I year 9 months at a chronological age of 0.66 years (Z score 5.37). After MDT discussions we commenced Cyproterone acetate 10 mg BD (50 mg/m²/day) rather than Anastrozole as there was increased risk of torsion with the latter. We also involved the surgical team and agreed surveillance scans 2 weekly. Given the cyclical nature of cysts, surgical intervention would only provide short-term solution with high chance of ovarian damage. Over the coming months we continued surveillance with regular scans. Follow up oestradiol levels rose (~3000 pmol/l) with increase in ovarian cyst size. This waxing and waning pattern of the ovarian cyst despite being on Cyproterone acetate warranted further treatment. Tamoxifen was added to block the effect of oestradiol on the uterus and bone age. She has radiological evidence of fibrous dysplasia involving the orbit but no evidence of compression on optic nerve.

Conclusion: This case highlights complexity involved in management of ovarian cysts in infancy.