Tumours in children and adolescents with Turner syndrome and Klinefelter syndrome: a retrospective Chinese cohort study.

Purpose: To analyse the incidence and characteristics of tumours diagnosed during childhood or adolescence in patients with Turner syndrome (TS) and Klinefelter syndrome (KS).

Methods: A retrospective analysis was conducted on clinical information of children diagnosed with TS and KS between 2010 and mid-2024. Meanwhile, the number of children with concomitant tumours was determined, and the incidence was analysed.

Result: A total of 23 individuals (median age 10 years, range: after birth to 16 years) with tumours were identified among the 657 children with TS and KS (median age=9 years, range: birth to 18 years), resulting in a tumour incidence of 3.50%. Within a cohort of 560 TS cases (median age 9 years, range: birth to18 years), 20 (3.57 %) were diagnosed with tumours. In a cohort of 97 KS cases (median age 4.3 years, range: 1-16 years), three (3.09 %) cases were diagnosed with tumours. The most common tumours in TS were osteochondroma (n=7) and haemangioma (n=6), with an estimated incidence of 1.25% and 1.07%, followed by gonadoblastoma (n=2), with an incidence of 0.36% in all TS and 4.44% in TS presenting with Y-chromosome material. In patients with KS, haemangioma (n=1), acute lymphoblastic leukaemia (n=1) and germ cell tumours (n=1) were observed. The co-occurrence of hepatic haemangiomas, mixed-phenotype acute leukaemia in TS, and the karyotypes (48,XXY,+21) of patient with intracranial germ cell tumours have not been previously reported.

Conclusion: Early-diagnosed TS and KS present with a variety of tumours in affected children, with osteochondromas representing the most prevalent in early diagnosed TS.