Teratoma — oncology-focused definition
A teratoma is a germ cell tumor composed of multiple types of tissues derived from more than one germ layer (ectoderm, mesoderm, and endoderm).
Key Characteristics:
- Can contain: hair, teeth, bone, muscle, neural tissue, or glandular tissue.
- Germ layers involved:
- Ectoderm: skin, hair, neural tissue
- Mesoderm: muscle, bone, cartilage
- Endoderm: gut epithelium, respiratory epithelium
Clinical relevance:
- Location:
- Ovarian teratomas (most common in females)
- Testicular teratomas (males, often part of mixed germ cell tumors)
- Mediastinum, sacrococcygeal region (rare sites)
- Behavior:
- Mature teratomas → usually benign
- Immature teratomas → potentially malignant, can metastasize
- Teratomas with malignant transformation → rare, aggressive cancers arise from somatic tissue within the teratoma
Diagnostic features:
- Imaging: CT/MRI may show cystic and solid components, sometimes with calcifications.
- Serum markers: Sometimes elevated AFP or β-hCG if associated with other germ cell components.
- Histology: Shows tissue from multiple germ layers, sometimes immature neuroepithelium in malignant cases.
Key takeaway:
A teratoma is a germ cell tumor containing tissues from multiple germ layers, with behavior ranging from benign to malignant depending on maturity and histologic features.
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