ESPE Abstracts

Background: Management of gynaecomastia in adolescent males with Partial Androgen Insensitivity Syndrome (PAIS) remains a clinical conundrum. The main mode of treatment is mastectomy, while literature on pharmaceutical management is limited. This case series evaluates outcome of 3 children treated with tamoxifen.

Case 1: A 16-year-old-boy with genetically confirmed PAIS, presented with bilateral gynaecomastia at 11 years of age. He had severe under-virilization of genitalia at birth and stretched phallic length (SPL) remained at 2 cm despite testicular enlargement and elevated serum testosterone levels. Tamoxifen 10 mg daily was started at the age of 13 years. Pre-treatment palpable glandular breast tissue measured 8×10 cm bilaterally with contours compatible with Tanner Stage-3. Tamoxifen therapy curtailed further progression of breast development, and substantially reduced granularity. Tamoxifen was continued for 3 years without significant side effects. Currently mastectomy is being contemplated due to persistence of gynaecomastia and considering patient’s preference.

Cases 2 and 3: Two brothers with 46XY DSD (presumed PAIS), currently aged 16 and 14 years, born with micropenis and penoscrotal hypospadias, were also given a trial of tamoxifen. Elder sibling presented with gynaecomastia at 13.5 years with bilateral testicular volumes of 6-8 ml, SPL of 4.5 cm and elevated serum testosterone levels. By 14 years’ breast tissue had increased to 5×5 cm bilaterally. Subsequently tamoxifen 10mg daily was started and continued for 2 years. In the first year of therapy, breast tissue reduced to 3×3 cm, and remained stable thereafter. The younger brother was commenced on tamoxifen at the age of 13 years when he presented with bilateral gynaecomastia (right breast 3 × 4 cm; left breast 2×2 cm). He has been on therapy for one year, with gradual regression of glandular breast tissue (right breast 2.5 × 3 cm, left breast non-palpable). At present, his testicular volume is 10-12 cm bilaterally, with a SPL 3 cm and pubic hair compatible with Tanner Stage 2. Both brothers report a reduction in psychological distress, lack of adverse effects and would like to continue therapy for longer.

Discussion: Treatment of gynaecomastia in PAIS, by irreversible procedures such as mastectomy, is best deferred until they develop a stable gender identity, and are mature enough to participate in informed decision making. Early use of tamoxifen appears to a viable interim measure to reduce progression of gynecomastia and provide psychological relief to affected adolescents.