Germ-cell tumors of the central nervous system in Peking Union Medical College Hospital: A 20-year clinicopathologic review

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Germ-cell tumors of the central nervous system in Peking Union Medical College Hospital: A 20-year clinicopathologic review

Central nervous system (CNS) germ-cell tumors (GCTs) are rare but impactful cancers that primarily affect children and adolescents. While research from Japan and other East Asian countries shows these tumors are more common in males and often arise in the pineal or sellar regions, large-scale data on Chinese patients have been limited. To fill this gap, a team from Peking Union Medical College Hospital (PUMCH) in Beijing analyzed 20 years of pathology records to characterize the clinicopathologic features of CNS GCTs in their patient population.

Led by Zhen Huo, a pathologist in PUMCH’s Department of Pathology (part of the Chinese Academy of Medical Sciences & Peking Union Medical College), the study reviewed 163 CNS GCT cases diagnosed between 1999 and 2019. All cases were confirmed by optical microscopy and immunohistochemical (IHC) staining—tests that use antibodies to identify tumor-specific proteins.

Key Findings: Tumor Types and Patient Demographics

The 163 patients ranged in age from 3 to 45 years (average: 16.4 years), with a slight female predominance (89 females vs. 74 males)—a contrast to most global studies, which report more males. Here’s how the tumors broke down:

  • Germinoma: The most common type (76.1%, 124 cases). Germinomas are highly sensitive to radiation, with cure rates exceeding 90% when treated early.
  • Teratoma: 14.7% (24 cases), including mature (21 cases, non-cancerous), immature (2 cases, partially developed), and 1 case with malignant transformation (benign tissue turning cancerous).
  • Mixed GCT (MGCT): 8% (13 cases), combining two or more GCT types (e.g., germinoma + teratoma + yolk sac tumor).
  • Rare types: Embryonal carcinoma (0.6%, 1 case) and yolk sac tumor (YST, 0.6%, 1 case). No pure choriocarcinoma (a fast-growing GCT) was found.

Germinoma: The Most Common and Treatable Type

Germinomas were not only the most frequent pure tumor but also a key component of mixed GCTs (134 total cases with germinoma). All tested positive for three critical markers:

  • CD117: A protein on germ cells.
  • OCT3/4: A stem cell marker.
  • Placental alkaline phosphatase (PLAP): A marker for germ cells.

Most germinomas (108 cases) arose in the sellar/suprasellar region—the area around the pituitary gland—with smaller numbers in the pineal gland (6 cases), basal ganglia (5 cases), or other brain regions. The sex ratio for pure germinomas was 49 males to 75 females, reinforcing the study’s unexpected female predominance.

Teratoma: Spinal Location and Mature Tissues

Teratomas—tumors that form multiple tissue types (e.g., hair, cartilage, muscle)—were most common in the intravertebral (spinal) region (14 cases). Most were mature (21 cases), meaning tissues were fully developed and non-cancerous. Teratoma patients were older on average (24.5 years) than those with germinomas.

Mixed GCTs: Younger Patients and Complex Combinations

Mixed GCTs (13 cases) included combinations of germinoma, teratoma, YST, choriocarcinoma, and embryonal carcinoma. These tumors affected younger patients (average age: 10 years) and were most common in the sellar (6 cases) or pineal (4 cases) regions. One mixed GCT contained choriocarcinoma cells, which tested positive for human chorionic gonadotropin (hCG)—a hormone linked to pregnancy.

Rare Tumors: Embryonal Carcinoma and YST

The two rarest tumors were both found in 13-year-old males:

  • Embryonal carcinoma: Located in the sellar/suprasellar region, tested positive for AE/AE3 (a broad cancer marker) and CD30 (a marker for aggressive germ cells).
  • YST: Found in the sellar region, positive for alpha-fetoprotein (AFP) (a liver/germ-cell cancer marker) and SALL4 (a stem cell marker).

How These Findings Compare to Global Data

The study aligned with global trends in one key way: CNS GCTs are most common in adolescents. But it stood out in two critical areas:

  1. Female predominance: Most studies (including Japan’s) report more males, but PUMCH’s cohort had slightly more females.
  2. Sellar region as top location: While pineal GCTs are common in other East Asian populations, PUMCH saw more sellar region tumors—likely due to referral patterns to a top pituitary specialty hospital.

Clinical Takeaways

For patients and clinicians, the study underscores:

  • Germinoma’s curability: Thanks to radiation sensitivity, early diagnosis saves lives.
  • Importance of IHC: Markers like CD117 and OCT3/4 are critical for accurate diagnosis.
  • Chinese patient uniqueness: The female predominance and sellar location highlight the need for population-specific research.

All patients provided consent for their clinical information to be used in the study. The authors declared no conflicts of interest.

This study was published in the Chinese Medical Journal in 2020. You can access the full paper at doi.org/10.1097/CM9.0000000000000606

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