Mediastinal tumor and Klinefelter's syndrome

Klinefelter syndrome in males with germ cell tumors: A report from the Children's Oncology Group

BACKGROUND

Males with Klinefelter syndrome (KS) (47,XXY) may be more likely to develop germ cell tumors (GCTs), particularly mediastinal GCTs. To date, there are no reports characterizing the prevalence of KS among male GCT cases.

METHODS

The authors used array genotyping data from a Children's Oncology Group epidemiology study to estimate the prevalence of KS in males with GCTs (433 males aged birth-19 years). Using Fisher's exact tests, the authors examined differences in age at diagnosis, race/ethnicity, tumor location and histology, and several birth characteristics between cases of KS-GCT and GCT cases without chromosomal abnormalities. Using publicly available data, the authors estimated the 1-year risk, risk ratio, and corresponding 95% confidence interval of GCTs among KS cases.

RESULTS

Based on analysis of array genotyping data, 3% of male GCT cases (13 cases) had KS. The additional X chromosome was of maternal origin in 7 of the 13 cases. Of these 13 KS cases, 5 of 9 KS-GCT cases with parental questionnaire data (56%) reported a diagnosis of KS. No significant differences were observed with regard to patient or birth characteristics between KS-GCT and non-KS-GCT cases. KS-GCT cases were significantly more likely to be diagnosed with mediastinal tumors than non-KS-GCT cases (P<.01). The authors estimated the risk of developing a GCT among males with KS to be 0.00025, or 1 per 4000 males (risk ratio, 18.8; 95% confidence interval, 11.7-30.0).

CONCLUSIONS

Compared with males without chromosomal abnormalities, males with KS are more likely to be diagnosed with a mediastinal GCT. The presence of KS should be considered in males with a diagnosis of mediastinal GCT. In the current study, the authors report that approximately one-third of males with mediastinal germ cell tumors have Klinefelter syndrome, and therefore screening of these individuals for the syndrome may be warranted. Males with Klinefelter syndrome are 19 times as likely as males without Klinefelter syndrome to develop germ cell tumors.

Klinefelter syndrome and mediastinal germ cell tumors

Precocious puberty is not a typical manifestation of patients with Klinefelter syndrome (KS). However, there is an increased incidence of mediastinal germ cell tumors (M-GCT) in KS, whereas the discussion of a generally higher tumor risk in this condition is still controversial. A rare subgroup of KS patients consists of prepubertal children with precocious puberty due to human chorionic gonadotropin (hCG)-producing M-GCTs. We present clinical data on a boy with KS and sexual precocity, and summarize the published data on 12 boys with KS out of 54 cases of KS and M-GCT.

CLINICAL REPORT

an 8.5-year-old boy presented with signs of precocious puberty. Laboratory analyses (suppressed gonadotropins, elevated testosterone) and thoracic CT demonstrated a beta-human chorionic gonadotropin (beta-hCG) and alpha(1)-feto protein (alpha-FP) secreting mediastinal tumor. Histological analysis showed a mixed germ cell tumor comprising choriocarcinoma (CH), embryonal carcinoma (EC), mature teratoma (MT), and yolk sac tumor (YS). He was successfully treated by surgery and adjuvant chemotherapy. Epianalysis of published cases: all KS patients (n = 12), age 4-9 years, presented with precocious sexual development (PP), whereas the older ones showed thorax-associated symptoms, mainly chest pain, dyspnea, and cough. The histological distribution was also age-dependent with mixed germ cell tumors predominantly in younger patients. Thus, M-GCTs are strongly associated with precocious puberty in young boys with KS. Therefore, a karyotype analysis should be included in the clinical work-up of boys with precocious puberty and M-GCT. There is still no convincing explanation for the association of M-GCTs and KS.

Second trimester prenatal diagnosis of epignathus teratoma in ring X chromosome mosaicism with inactive ring X chromosome

We report the second trimester prenatal echographic diagnosis of an epignathus teratoma in a female fetus with ring X chromosome mosaicism. The ring X chromosome mosaicism was present in the amniotic cell culture and in the teratoma and the ring X was inactive (X-inactive specific transcript (XIST) locus expressed). Hypoplastic left heart with valvular aortic stenosis and non-immune hydrops were additional findings, and are well-documented in Turner syndrome. The occurrence of epignathus teratoma in Turner syndrome has not been documented sofar.