teratoma

Teratoma is a type of germ cell tumor arising from pluripotent cells capable of differentiating into tissues from more than one germ layer (ectoderm, mesoderm, and endoderm). Teratomas can contain a variety of mature tissues such as hair, teeth, fat, or bone, or immature or malignant tissue. They are broadly categorized as mature (benign), immature (potentially malignant), or malignant with somatic-type transformation.

Most teratomas occur in the ovaries of women (m ovarian teratoma being the most common), but they can arise in other locations, including the sacrococcygeal region in newborns, the testis, and extragonadal sites such as the mediastinum, retroperitoneum, and brain. Ovarian mature teratomas are often referred to as dermoid cysts. Immature teratomas are more common in children and adolescents and carry a higher risk of malignant behavior, while mature teratomas carry a favorable prognosis after complete surgical removal.

Pathologically, teratomas reflect tissues from multiple germ layers and may form well-differentiated elements or, in immature cases, primitive neural tissue and other immature components. Malignant transformation can occur in mature teratomas, though rarely, and may produce somatic-type cancers (e.g., squamous cell carcinoma) within the teratoma.

Clinical presentation varies by location. Ovarian teratomas may be asymptomatic or cause abdominal pain or mass effect; sacrococcygeal teratomas present as neonatal masses and can be detected prenatally. Diagnosis relies on imaging (ultrasound, MRI, CT) and, when indicated, tumor markers (AFP, hCG). Treatment for localized disease is surgical excision; chemotherapy is used for immature or malignant cases. Prognosis is excellent for surgically resected mature teratomas, while immature or malignant teratomas require ongoing oncologic management.