MALIGNANT GONADAL TUMOUR IN TRISOMY 21 WITH COMPLETE SEX REVERSAL

Abstract

INTRODUCTION/BACKGROUND
Trisomy 21 is a chromosomal disorder with a high incidence worldwide. It is associated with characteristic physical features, delay in development and some congenital organ defects. However, disorder of sex development (DSD) is not usually seen in patients with Down Syndrome.

CASE
A 14-year-old phenotypically female with Down syndrome presented with a two-month history of progressive abdominal swelling, constipation and weight loss. At birth, typical Down Syndrome facial features were present and the female gender was assigned. The karyotype result of 86 cells showed 47XY, +21 with +SRY gene via FISH study. Pelvic ultrasound at 2 months showed the presence of a uterus and 2 ovaries. A β-hCG stimulation test performed exhibited a suboptimal response: serum testosterone increased to 1.2 nmol/L from a baseline of 0.7 nmol/L. The patient subsequently failed to turn up after a planned diagnostic laparoscopy was cancelled. At the current presentation, the patient was short and thin. Female pubertal changes were present. The abdomen was distended with a firm rounded palpable mass measuring 20 x 15 cm. There were no findings of clitoromegaly nor palpable gonads. Primary gonadal failure was evident from high serum gonadotropins and disproportionately low levels of oestrogen and testosterone. Abdomen CT showed a highly vascularised mass arising from the anterior abdomen with multiple septations of mixed cystic and solid components with calcifications; the uterus and two ovaries were seen. Laparotomy revealed a huge mass measuring 15 cm x 16 cm x 6 cm and two gonad-like structures with bridging Müllerian structures and abnormal-looking lymph nodes. Histopathology revealed dysgerminoma and gonadoblastoma of the huge mass and the gonads and metastatic changes in the lymph nodes. A PET scan showed metastasis to the right lung. The patient underwent chemotherapy subsequently.

CONCLUSION
DSD in Down Syndrome with Y chromosome is at high risk of gonadal tumour. Prevention and early detection are possible with the continuation of surveillance and meticulous assessments.