Spectrum of Germ Cell Tumors: From Head to Toe

Abstract

Germ cell tumors (GCTs) occur most frequently in the gonads and are relatively rare in other sites, such as the pineal gland, neurohypophysis, mediastinum, and retroperitoneum. GCTs are thought to originate from primordial germ cells, which migrate to the primitive gonadal glands in the urogenital ridge. Extragonadal GCTs might also originate from these cells when the cells are sequestered during their migration. Pathologic subtypes of GCTs vary, and the prevalence of mixed tumors is high. These factors produce a diversity of radiologic findings and make prospective radiologic diagnosis difficult in many cases. However, similar radiologic findings have been observed in pathologically equivalent tumors in varying sites. Seminomas appear as uniformly solid, lobulated masses with fibrovascular septa that enhance intensely. Nonseminomatous GCTs appear as heterogeneous masses with areas of necrosis, hemorrhage, or cystic degeneration. Fat and calcifications are hallmarks of teratomas, most of which are benign. In immature teratomas, scattered fat and calcification within larger solid components are occasionally seen. These imaging characteristics reflect the pathologic features of each tumor, and histologically similar GCTs at varying sites have similar radiologic features. Knowledge of the pathologic appearances of GCTs and their corresponding radiologic appearances will allow radiologists to diagnose these tumors correctly.

A calcific pelvic mass in a woman with chronic spinal pain: a case of mature cystic teratoma

“…Extragonadal germ cell tumors occur in the median line of the body, with the anterior mediastinum, sacrococcygeal region, pineal gland, and neurohypophysis being common sites. 7 Mature cystic teratomas are benign teratomas that develop from an individual nontransformed germ cell after the first meiotic division. 5,9 The cystic component of these masses is commonly a greasy liquid composed of keratin, sebum, and hair encased in a firm capsule of variable thickness.…”

“…6 Mature teratomas are principally cystic and lined by epithelium. 7 Because of the predominance of skin elements, mature cystic teratomas are also referred to as dermoid cysts. 4 Mature cystic teratomas, in their pure form, are always benign, although they may rarely undergo malignant transformation.…”

Extragonadal teratomas of the adult abdomen and pelvis: a pictorial review

“…6 In prepubertal children, the immature elements within a teratoma are not associated with malignant behaviour; however, in adults, mediastinal immature teratomas can be aggressive with a poor prognosis. 1,7 More rarely, teratomas may contain frankly malignant components of several tissue lineages.…”

“…It should be noted that immature teratomas without prominent solid components can occasionally be seen. 6 Alpha-fetoprotein tumour markers can be of assistance in distinguishing malignancy but may be only raised in up to 50% of the cases. 6 MALIGNANT TRANSFORMATION Malignant transformation in MCT is rare and reported to be between 1% and 12.5% for sacrococcygeal lesions.…”

“…6 Alpha-fetoprotein tumour markers can be of assistance in distinguishing malignancy but may be only raised in up to 50% of the cases. 6 MALIGNANT TRANSFORMATION Malignant transformation in MCT is rare and reported to be between 1% and 12.5% for sacrococcygeal lesions. 4 The most common malignancies arising in teratomas are squamous carcinoma, carcinoid tumour and adenocarcinoma, 4 with neuroendocrine carcinoma and extramammary Paget's disease also rarely described.…”