ESPE Abstracts

Introduction: Peutz-Jeghers syndrome (PJS) is a disorder characterized by autosomal dominant inheritance, hamartomatous polyps in the gastrointestinal system, mucocutaneous pigmentation, and a predisposition to malignancies, caused by mutations in the STK11 gene. In male patients, large cell calcifying Sertoli cell tumors associated with prepubertal gynecomastia can be observed. We present a case of prepubertal gynecomastia that led to a diagnosis of PJS during follow-up.

Case: A 6-year-old male patient presented with a two-year history of bilateral breast enlargement. Physical examination revealed a height of 126.5 cm (1.63 SD), weight of 23.5 kg (0.49 SD), body mass index of 14.69 kg/m² (-0.61 SD), bilateral stage 3 gynecomastia, and hyperpigmented freckling on the lips. Testicular volumes were 6/5 ml with a stretched penile length of 5.7 cm. Complete blood count, biochemistry, and thyroid function tests were normal. Hormonal profile showed FSH < 0.3 IU/L, LH 0.43 IU/L, total testosterone <2.5 ng/dL, estradiol 12.9 ng/dL, AFP 2.35 µg/L (<3.63), beta-HCG <0.2 IU/L, DHEASO4 12.4 µg/L, prolactin 24.4 mcg/L, with a bone age of 10 years. LH-RH stimulation test results were prepubertal. Scrotal ultrasonography showed bilateral microlithiasis and coarse calcified areas in the upper and lower poles. Breast ultrasonography revealed 1 cm of fibroglandular breast tissue bilaterally. Detailed questioning revealed that the patient’s father had undergone polyp removal post-intussusception and his grandfather died from colon cancer. A rectal polyp biopsied when the patient was two years old was assessed as a juvenile polyp. An endoscopy performed as part of the PJS diagnostic process revealed five broad-based polyps measuring 1.5 cm in the stomach and smooth-surfaced, stalked polyps measuring 2 cm in the jejunum, pathologically classified as hyperplastic. Testicular biopsy showed immature testicular tissue. Karyotype analysis confirmed 46,XY (SRY+). DNA sequencing of the STK11 gene did not identify any mutations; therefore, MLPA was planned due to the clinical consistency with PJS. To prevent progression of gynecomastia and advanced bone age, treatment with 2.5 mg/day of letrozole was initiated. After seven months, regression of gynecomastia and halting of bone age advancement were observed.

Conclusion: Peutz-Jeghers Syndrome (PJS) is a rare but important consideration in cases of prepubertal gynecomastia. This case highlights the effectiveness of letrozole, an aromatase inhibitor, in halting the progression of gynecomastia and advanced bone age associated with PJS. Early intervention can significantly improve outcomes in young patients with this rare condition.

Keywords: Peutz-Jeghers syndrome, prepubertal gynecomastia, large cell calcifying Sertoli cell tumor, letrozole