Germ-Cell Tumors of the Central Nervous System in Peking Union Medical College Hospital: A 20-Year Clinicopathologic Review
Germ-cell tumors (GCTs) of the central nervous system (CNS) are rare neoplasms that primarily affect children and adolescents. These tumors share morphological, immunophenotypic, and, in some respects, genetic similarities with gonadal and other extraneuraxial germ-cell neoplasms. The diagnosis of GCTs of the CNS is relatively straightforward, with the major types being germinoma, teratoma, yolk sac tumor (YST), embryonal carcinoma, and choriocarcinoma. Neoplasms that contain multiple types of GCTs are classified as mixed GCTs (MGCTs). The peak incidence of GCTs of the CNS occurs in patients aged 10 to 14 years, with a clear majority of cases involving males. Interestingly, GCTs of the CNS appear to be more prevalent in eastern Asia compared to Europe and the United States.
The study conducted at Peking Union Medical College Hospital aimed to provide a comprehensive review of GCTs of the CNS diagnosed over a 20-year period, from 1999 to 2019. The study retrospectively analyzed 163 cases of GCTs of the CNS, focusing on their clinicopathologic features. The male-to-female ratio in this cohort was 74:89, with an age range of 3 to 45 years and an average age of 16.4 years. The most common type of GCT was germinoma, accounting for 76.1% of cases (124 cases), followed by teratoma (14.7%, 24 cases), MGCT (8.0%, 13 cases), embryonal carcinoma (0.6%, 1 case), and YST (0.6%, 1 case). No cases of pure choriocarcinoma originating in the CNS were identified.
Germinoma, the most prevalent type of GCT in this study, is known for its extreme sensitivity to radiotherapy, which contributes to high cure rates. Among the 134 cases with germinoma components (including 124 cases of pure germinoma), all were positive for CD117, octamer-binding transcription factor 3/4 (OCT3/4), and placental alkaline phosphatase. The male-to-female ratio in pure germinoma cases was 49:75, with an age range of 3 to 41 years and an average age of 15.7 years. The majority of germinomas occurred in the sellar and suprasellar regions (108 cases), with 38 cases involving only the sellar region. Other locations included the pineal gland (6 cases), basal ganglia (5 cases), periventricular region (3 cases), corpus callosum (1 case), and brain lobe (1 case). In cases involving the sellar and suprasellar regions, additional involvement of the pineal body (23 cases), hypothalamus (12 cases), ventricles (10 cases), basal ganglia (4 cases), corpus callosum (2 cases), and septum pellucidum (1 case) was observed. One case of germinoma contained syncytiotrophoblastic giant cells.
Teratomas, the second most common type of GCT in this study, were diagnosed in 24 cases, with an age range of 11 to 45 years and an average age of 24.5 years. Teratomas accounted for 0.3% of all teratoma cases during the same period. The locations of teratomas included the intravertebral region (14 cases), intrasellar region (4 cases), pineal region (3 cases), suprasellar region (1 case), left frontal base (1 case), and middle cranial fossa (1 case). Teratomas were subclassified as mature, immature, or exhibiting malignant transformation. Among the 24 cases, 21 were mature teratomas, 2 were immature teratomas with primitive neuroectodermal elements (positive for CD99 and nestin), and 1 was a teratoma with malignant transformation, specifically a carcinosarcoma.
Mixed GCTs (MGCTs) were diagnosed in 13 cases, with a male-to-female ratio of 9:4, an age range of 5 to 28 years, and an average age of 10 years. MGCTs accounted for 13% of all MGCT cases during the same period. The sites of occurrence included the sellar region (6 cases), pineal region (4 cases), spinal canal (2 cases), and posterior third ventricle (1 case). The components of MGCTs included germinoma, mature teratoma, YST, choriocarcinoma (human chorionic gonadotrophin positive), immature teratoma, malignant transformation of teratoma, and embryonal carcinoma.
One case of embryonal carcinoma was identified in a 13-year-old male, located in both the sellar and suprasellar regions. This case accounted for 1.5% of all embryonal carcinoma cases during the same period and was positive for AE/AE3 and CD30. One case of YST was identified in a 13-year-old male, located in the sellar region. This case accounted for 1% of all YST cases during the same period and was positive for alpha-1-fetoprotein and spalt-like transcription factor 4.
The data from this study suggest that GCTs of the CNS predominantly affect adolescents, which is consistent with findings from other large-scale studies. However, this study observed a slightly higher prevalence of female patients, which contrasts with other studies that report a higher incidence in males. Germinoma was the most common type of GCT of the CNS, followed by teratoma and MGCT. The sellar region was the most common site for GCTs of the CNS in this cohort, followed by the pineal region, which may be related to patient selection. The intraspinal canal was the most common site for teratomas.
In conclusion, this 20-year clinicopathologic review provides valuable insights into the characteristics of GCTs of the CNS in a Chinese population. The findings highlight the predominance of germinomas, the varied locations of these tumors, and the slightly higher prevalence in female patients compared to other studies. The data contribute to a better understanding of GCTs of the CNS and may aid in the diagnosis and treatment of these rare neoplasms.
doi.org/10.1097/CM9.0000000000000606
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