Histologic Classification
Mature Teratomas
Immature Teratomas
Malignant Germ Cell Tumors
The childhood extracranial germ cell tumors comprise a variety of histologic
diagnoses and can be broadly classified into mature or immature teratomas and
malignant germ cell tumors (GCT).
Mature Teratomas
Mature teratomas generally occur in the ovary or at extragonadal locations and are the most common histological subtype of childhood GCT.[1-3] These teratomas usually contain well-differentiated tissues from the ectodermal, mesodermal, and endodermal germ cell layers, and any tissue type may be found among the tumor. Mature teratomas are benign, though some mature and immature teratomas may secrete enzymes or hormones, including insulin, growth hormone, androgens, prolactin, and vasopressin.[4-6]
Immature Teratomas
Immature teratomas also contain tissues from all three germ cell layers, but immature tissues, primarily neuroepithelial, are present. Immature teratomas can be graded from 0 to 3 based on the amount of immature tissue found in the tumor specimen.[7] Tumors of higher grade are more likely to have foci of yolk sac tumor.[8] Immature teratomas occur primarily in young children at extragonadal sites and in the ovaries of girls near the age of puberty, but there is no correlation between tumor grade and patient age.[8,9]
Malignant Germ Cell Tumors
GCT outside the central nervous system contain frankly malignant tissues of germ cell origin, or rarely, tissues of somatic origin. Isolated malignant elements may constitute a small fraction of a predominantly immature teratoma.[9,10] Malignant germ cell elements of children, adolescents, and young adults can broadly be classified by location (see Tables 2 and 3).
Table 2. Histology of Malignant Germ Cell Tumors in Young Children
Malignant Germ Cell Elements
|
Location
|
T = Testicular; O = Ovarian; E = Extragonadal
|
Yolk Sac Tumor |
T, O, E |
Dysgerminoma (rare in young children) |
O |
[Note: Modified from (Perlman EJ and Hawkins EP. Pediatric and Developmental Pathology 1, 328-335, 1998.)]
Table 3. Histology of Malignant Germ Cell Tumors in Adolescents and Young Adults
Malignant Germ Cell Elements
|
Location
|
T = Testicular; O = Ovarian; E = Extragonadal
|
Seminoma |
T |
Dysgerminoma |
O |
Germinoma |
E |
Yolk Sac Tumor |
T, O, E |
Choriocarcinoma |
T, O, E |
Embryonal Carcinoma |
T |
Mixed Germ Cell Tumors |
O, E |
[Note: Modified from (Perlman EJ and Hawkins EP. Pediatric and Developmental Pathology 1, 328-335, 1998.)]
Yolk sac tumors produce alpha-fetoprotein (AFP), while germinomas (seminomas and dysgerminomas), and especially choriocarcinomas, produce beta-human chorionic gonadotropin, resulting in the elevated serum levels of these substances. Most children with malignant GCT will have a component of yolk sac tumor and have elevations of AFP,[11,12] which is serially monitored during treatment to help assess response to therapy.[9-11]
Adolescents and young adults present with more germinomas (testicular and mediastinal seminomas in males and ovarian dysgerminomas in females). These tumors are usually treated with chemotherapy but are also sensitive to radiation therapy.
References
-
Göbel U, Calaminus G, Engert J, et al.: Teratomas in infancy and childhood. Med Pediatr Oncol 31 (1): 8-15, 1998.
[PUBMED Abstract]
-
Rescorla FJ: Pediatric germ cell tumors. Semin Surg Oncol 16 (2): 144-58, 1999.
[PUBMED Abstract]
-
Harms D, Zahn S, Göbel U, et al.: Pathology and molecular biology of teratomas in childhood and adolescence. Klin Padiatr 218 (6): 296-302, 2006 Nov-Dec.
[PUBMED Abstract]
-
Tomlinson MW, Alaverdian AA, Alaverdian V: Testosterone-producing benign cystic teratoma with virilism. A case report. J Reprod Med 41 (12): 924-6, 1996.
[PUBMED Abstract]
-
Lam SK, Cheung LP: Inappropriate ADH secretion due to immature ovarian teratoma. Aust N Z J Obstet Gynaecol 36 (1): 104-5, 1996.
[PUBMED Abstract]
-
Kallis P, Treasure T, Holmes SJ, et al.: Exocrine pancreatic function in mediastinal teratomata: an aid to preoperative diagnosis? Ann Thorac Surg 54 (4): 741-3, 1992.
[PUBMED Abstract]
-
Norris HJ, Zirkin HJ, Benson WL: Immature (malignant) teratoma of the ovary: a clinical and pathologic study of 58 cases. Cancer 37 (5): 2359-72, 1976.
[PUBMED Abstract]
-
Heifetz SA, Cushing B, Giller R, et al.: Immature teratomas in children: pathologic considerations: a report from the combined Pediatric Oncology Group/Children's Cancer Group. Am J Surg Pathol 22 (9): 1115-24, 1998.
[PUBMED Abstract]
-
Marina NM, Cushing B, Giller R, et al.: Complete surgical excision is effective treatment for children with immature teratomas with or without malignant elements: A Pediatric Oncology Group/Children's Cancer Group Intergroup Study. J Clin Oncol 17 (7): 2137-43, 1999.
[PUBMED Abstract]
-
Göbel U, Calaminus G, Schneider DT, et al.: The malignant potential of teratomas in infancy and childhood: the MAKEI experiences in non-testicular teratoma and implications for a new protocol. Klin Padiatr 218 (6): 309-14, 2006 Nov-Dec.
[PUBMED Abstract]
-
Mann JR, Raafat F, Robinson K, et al.: The United Kingdom Children's Cancer Study Group's second germ cell tumor study: carboplatin, etoposide, and bleomycin are effective treatment for children with malignant extracranial germ cell tumors, with acceptable toxicity. J Clin Oncol 18 (22): 3809-18, 2000.
[PUBMED Abstract]
-
Marina N, Fontanesi J, Kun L, et al.: Treatment of childhood germ cell tumors. Review of the St. Jude experience from 1979 to 1988. Cancer 70 (10): 2568-75, 1992.
[PUBMED Abstract]
Back to Top
< Previous Section | Next Section > |