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Germ Cell Tumors

16

 

Paul Imbach

 

Contents

16.1

Definition ...................................................................................................................

175

16.2

Incidence

...................................................................................................................

176

16.3

Pathogenesis...............................................................................................................

176

16.4

Genetics

...................................................................................................................

177

16.5

Histological Classification .........................................................................................

177

16.6

Diagnostics.................................................................................................................

177

16.7

Therapy: Overview ....................................................................................................

178

16.8

Testicular Germ Cell Tumors and Subtypes ..............................................................

178

 

16.8.1

Testicular Yolk Sac Tumor.........................................................................

179

 

16.8.2

Testicular Teratoma....................................................................................

179

 

16.8.3

Testicular Embryonal Carcinoma ..............................................................

180

 

16.8.4

Testicular Teratocarcinoma........................................................................

180

 

16.8.5

Testicular Seminoma (in Adults) ...............................................................

180

16.9

Ovarian Tumors and Subtypes...................................................................................

180

 

16.9.1

Ovarian Teratoma.......................................................................................

181

 

16.9.2

Ovarian Dysgerminoma.............................................................................

181

 

16.9.3

Ovarian Yolk Sac Tumor............................................................................

181

 

16.9.4

Ovarian Mixed-Cell Malignant Germ Cell Tumor ....................................

182

 

16.9.5

Embryonal Carcinoma of the Ovary..........................................................

182

 

16.9.6

Ovarian Gonadoblastoma ..........................................................................

182

16.10 Extragonadal Germ Cell Tumors Subtypes ...............................................................

182

 

16.10.1

Sacrococcygeal Teratoma ..........................................................................

182

 

16.10.2

Intracranial Teratoma.................................................................................

183

 

16.10.3

Mediastinal Teratoma ................................................................................

183

16.1Definition

Tumors develop from embryonal germ cells and may have tumor constituents representing ectodermal, mesodermal, and endodermal lineages

P. Imbach et al. (eds.), Pediatric Oncology,

175

DOI 10.1007/978-3-642-20359-6_16, © Springer-Verlag Berlin Heidelberg 2011

 

176

P. Imbach

 

 

16.2Incidence

2.5% of all neoplasia in children

Annually, 2–4 children in one million less than 16 years old are newly diagnosed with germ cell tumors

Bimodal age distribution: (a) infancy and early childhood, male to female ratio 6:1, (b) increase during late childhood and adolescence, male to female ratio 1:3

Inherited syndromes may be associated with germ cell tumor often demonstrating genetic alterations such as Klinefelter syndrome, Fraser syndrome, Russell–Silver syndrome, Down syndrome, ataxia telangiectasia, and others

Site and frequency of extragonadal tumors: Ovary 25–30%, coccyx 15–20%, CNS 20–25%, mediastinum 5–7%, other sites 5–10% (vagina, uterus, prostata, retroperitoneum, thyroid)

16.3Pathogenesis

At 4th or 5th week of gestation, extraembryonic germ cells migrate to gonadal ridge of the embryo

At 6th or 7th week of gestation: after sex differentiation in the gonadal ridge

Ovarian differentiation to oocytes

Spermatocytes form if Y chromosome is present

Extragonadal germ cell tumors of children develop after aberrant migration of germ cells, resulting in germ cell tumors that can occur in any midline structure, including midbrain, mediastinum, and sacrococcyx, depending on where the aberrantly migrating germ cells settle, but these are nearly always midline.

Classification of gonadal and extragonadal tumors

AGerm cells and germinoma/dysgerminoma and embryonal yolk sac tumor (pluripotent cells):

(a)Extraembryonic structures:

Yolk sac or endodermal sinus tumor

Choriocarcinoma

(b)Embryonal ecto- ,meso- ,endodermal origin tissues represented:

Teratoma

(c)Embryonal carcinoma

BGonadal germ cells and stroma tumors (Sertoli and Leydig cells)

CEpithelial cells (ovarian origin) and granulosa cell tumor or mixed form, as well as epithelial cell tumors more common in adults

16 Germ Cell Tumors

177

 

 

16.4Genetics

Ovarian germ cell tumor of adolescents:

Mature teratoma with normal karyotype

Immature teratoma with heterogeneous karyotype: partly isochromosome 12p, either diploid (mostly in grade I or II tumors) or aneuploid (grade III tumors)

Malignant ovarian tumor: aneuploidy and isochromosome 12p and/or alteration of chromosomes 21, 1q13, and 8

Testicular germ cell tumor of adolescents:

Aneuploidy and isochromosome 12p

Loss of heterogeneity on chromosomes 12q13 and 12q22

16.5Histological Classification

Classification of gonadal/extragonadal tumors

 

 

A. Gonadal tumors

 

 

 

With germ cell characteristics

Without germ cell characteristics

Females

Males

Females

Males

Teratoma

Yolk sac tumor

Epithelial carcinoma:

Leydig cell tumor

Dysgerminoma

Embryonal

Granulosa, Sertoli,

Sertoli cell tumor

 

carcinoma

Leydig cell tumors

 

Embryonal carcinoma

Teratoma

Mixed tumor

 

Mixed-cell tumor

Teratocarcinoma

 

 

Choriocarcinoma

Gonadoblastoma

 

 

Gonadoblastoma

Seminoma (adult)

 

 

 

Choriocarcinoma

 

 

 

Mixed-cell

 

 

 

carcinoma

 

 

B. Extragonadal tumors (sacral, mediastinal, retroperitoneal, pineal region, rarely in other areas)

Teratoma ± yolk sac tissue

Teratoma ± embryonal carcinoma

16.6Diagnostics

Clinical manifestations: see particular germ cell tumors

Radiological diagnosis: ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI)

Tumor markers

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