Extragonadal teratoma

Extragonadal teratoma is a rare germ cell tumor that arises outside the gonads (ovaries and testes), developing instead in midline or para-axial locations of the body. These tumors are thought to originate from primordial germ cells that failed to migrate properly during embryonic development. The most common sites include the sacrococcygeal region (particularly in neonates and infants), the anterior mediastinum, the retroperitoneum, and intracranial locations such as the pineal or suprasellar regions. Teratomas are composed of tissues derived from all three embryonic germ layers (ectoderm, mesoderm, and endoderm) and may contain mature (well-differentiated) or immature (poorly differentiated) tissue elements. The ICD-10 classification D48.7 reflects the uncertain or borderline behavior of these neoplasms. Clinical presentation varies significantly depending on the tumor's location and size. Sacrococcygeal teratomas, the most common congenital tumors, may present as a visible mass at birth or may be detected prenatally on ultrasound. Mediastinal teratomas can cause chest pain, cough, dyspnea, or superior vena cava syndrome due to compression of thoracic structures. Retroperitoneal teratomas may cause abdominal pain, a palpable mass, or gastrointestinal or urinary symptoms. Intracranial teratomas can lead to headaches, visual disturbances, endocrine dysfunction, or hydrocephalus. While mature teratomas are generally benign, immature teratomas carry a risk of malignant transformation and may contain elements of other malignant germ cell tumor types (such as yolk sac tumor or embryonal carcinoma). Treatment primarily involves complete surgical resection, which is often curative for mature teratomas. For immature teratomas or those with malignant components, platinum-based chemotherapy (typically cisplatin-based regimens such as BEP — bleomycin, etoposide, and cisplatin) is used in addition to surgery. Serum tumor markers, including alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (beta-hCG), are important for diagnosis, staging, and monitoring treatment response. Prognosis depends on the tumor's location, histological grade, completeness of surgical resection, and the presence of malignant elements. Long-term follow-up is essential due to the risk of recurrence, particularly in cases of incomplete resection.

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