Case 90

A 46-year-old male with a diagnosis of testicular mixed germ cell tumor of choriocarcinoma and mature cystic teratoma. He was found to have a large inguinal lymph node.

1. How would you sign out this case?

   A: metastatic germ cell tumor

   B: metastatic malignant teratoma

   C: mature teratomatous elements involving lymph nodes

   D: metastatic mucinous adenocarcinoma

   
   
   
   

Answer

The case was called mature teratomatous elements in 2 lymph nodes as it does not demonstrated any malignant features as well as any area of choriocarcinoma. However, the presence of it in lymph node is very unusual and certainly raises the possibility of LN metastasis.

Per CAP protocol: Pure teratomatous metastasis, unless accompanied by somatic-type malignancy, is generally treated by surgical excision alone, whereas patients who have other residual germ cell tumor components are usually treated with additional chemotherapy.

• Mature teratomas are a common post-chemotherapy finding in metastatic NSGCT.

• They arise due to:

  • Selective resistance of teratoma to chemotherapy

  • High chemosensitivity of embryonal components

• Growing Teratoma Syndrome (GTS):

  • Defined by an enlarging residual mass

  • Histologically confirmed mature teratoma

  • Normal tumor markers (e.g., AFP, hCG)

• GTS is rare but clinically important.

• Metastatic mature teratomas must be resected:

  • Due to potential for malignant transformation

  • Risk of local invasion

• CT imaging is the modality of choice for post-treatment surveillance.

• Surveillance should include all potential metastatic sites.

Reference: https://documents.cap.org/protocols/Testis.RPL_4.2.1.0.REL_CAPCP.pdf?_gl=1*1kptco8*_ga*MTI2Mjc4MjcwMS4xNzE5NjcwNTUw*_ga_97ZFJSQQ0X*MTc0MzYwOTkyOC40MS4wLjE3NDM2MDk5MzMuMC4wLjA.

Case credit: UCSD Pathology

Author: Wangpan Jackson Shi, MD