ESPE Abstracts

Background: Testicular tumours are an unusual cause of prepubertal gynecomastia. However, in boys with Peutz-Jeghers Syndrome (PJS), a rare autosomal dominant disorder caused by mutation in LKB1/STK11 gene, is mandatory to exclude this etiology, given the well-known association between PJS and Large-Cell Calcyfing Sertoli-Cell Tumor (LCCSCT). This mutation promotes aromatase overexpression in neoplastic Sertoli-cells, leading to gynecomastia.

Case presention: We report the case of a 4-year-old boy, with genetic diagnosis of PJS, who had been presenting gynecomastia since the age of 2 and a marked height velocity (HV). He exhibited hyperpigmented lesions of the lower-lip, bilateral breast enlargement (female Tanner-B4), absent pubic/axillary hair, infantile penis and testicular volume of 4 mL. His height was 110.5 cm(+1.88SDS) and HV was 8.64 cm/year(+2.65SDS). Bone and chronological age were coincident. LHRH test was performed, excluding GnRH-dependent precocious puberty, as well as abdominal MRI, that excluded adrenals’ oestrogen-producing tumour. Testicular ultrasound evidenced bilateral size of 22×10 mm and multifocal microcalcifications. Blood tests revealed: LH<0.20 mUI/mL, FSH <0.20 mUI/mL, oestradiol<20.0 pg/mL, testosterone <3.00 ng/dL, prolactin 5.4 ng/mL, androstenedione <0.30 ng/mL and inhibin-A 4.6 pg/mL(0.9–1.7). The diagnosis of LCCSCT was made given the patient’s syndrome and the ultrasound’s description. Considering the frequent benign nature of LCCSCT, we’ve chosen to perform conservative treatment with anastrozol. One year after the start of this drug the patient evidenced a less tense Tanner-B3 and a HV of 5.68 cm/year (−0.71SDS); serum inhibin-A had become negative (<0.4 pg/mL).

Conclusion: We describe the case of a boy with one of the most precocious PJS-related gynecomastia reported in the literature associated to a marked increase in HV. It has been described that, although oestrogen level may be under the detection limit, it can be sufficient to stimulate breast tissue and growth plates, probably due to increased tissular sensitivity/bioavailability/local biosynthesis. In this patient, the aromatase inhibitor has promoted reduction of breast volume, HV and serum inhibin-A.