Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder characterized by multiple gastrointestinal hamartomatous
polyps, mucocutaneous pigmentation and increased predisposition to
neoplasms. Endocrine manifestations in PJS include
gynecomastia and advanced bone age due to
estrogen production by large-cell calcifying Sertoli cell
tumors (LSCT). We present two 9-year-old male monozygotic twins, with PJS, bilateral progressive prepubertal
gynecomastia and testicular bilateral multifocal calcifications, suggesting a diagnosis of LSCT. Their father had PJS but no history of
gynecomastia or testicular calcifications. No mutations were found in the tumor suppressor gene LKB1/STK11, which is responsible for about 60% of PJS cases. The genotype of the
aromatase cytochrome P450 19, a key
enzyme involved in
estrogen biosynthesis, was the same in the father and his twins. To reduce
gynecomastia and delay skeletal maturation, the children started treatment with
anastrozole, an
aromatase inhibitor. Growth velocity decreased and
gynecomastia diminished. After 2 years of treatment,
anastrozole is still currently used at a dosage of 1 mg once daily with no side effects. In this study, a couple of monozygotic twins with PJS, prepubertal
gynecomastia and LSCT is reported for the first time and
anastrozole appears to be an efficacious medical treatment, as an alternative to
orchidectomy, to control the effects of
estrogen excess.