Pubertal gynaecomastia is common, occurring in up to 65% of healthy teenage boys. So how should we pick up those with significant pathology?

Here Vaidyanathan & Kaplowitz describe an otherwise healthy male aged 17 years 7 months, with sparse body hair, Tanner stage 3 breast development, Tanner 3 pubic hair and testes 15ml bilaterally. Blood levels were luteinising hormone (LH) 14.4µU/l, follicle-stimulating hormone 7.7µU/l, testosterone 1660ng/dl, oestradiol 64pg/ml, and karyotype was 46,XY.

Because of the under-virilisation, persistent gynaecomastia, high testosterone, elevated LH and oestradiol, a diagnosis of partial androgen insensitivity syndrome (PAIS) was considered. A novel A721T missense mutation was detected in the androgen receptor gene. The variant has been denoted as c.2161G>A at the c.dna level. The patient underwent bilateral mastectomy and decided against testosterone therapy.

Clearly this is a rare diagnosis, with PAIS having a prevalence of 1 in 20,000. This is another rare but important cause to consider when seeing patients with gynaecomastia.

Read the full article in Endocrinology, Diabetes & Metabolism Case Reports doi:10.1530/EDM-18-0128