MedGen

The division of a ZYGOTE into two parts that are each capable of further development into two distinct individuals, both that have the same genetic makeup. [from MeSH]

A radiosensitive malignant germ cell tumor found in the testis (especially undescended), and extragonadal sites (anterior mediastinum and pineal gland). It is characterized by the presence of uniform cells with clear or dense cytoplasm which contains glycogen, and by a large nucleus which contains one or more nucleoli. The neoplastic germ cells form aggregates separated by fibrous septa. The fibrous septa contain chronic inflammatory cells, mainly lymphocytes. [from NCI]

A rare benign proliferative disorder of the synovial membrane primarily affecting young adults (with a peak age of onset in the second to fourth decade of life) characterized by proliferative, locally invasive tumor-like lesions, usually involving a single joint, tendon sheath or bursa (most commonly the joints of the knee and hip and rarely others such as the ankle, shoulder and temporomandibular joints). It presents with pain and limitation of motion along with swelling, heat and tenderness over the involved joint, eventually leading to arthritic degeneration and significant locomotor deficit, if left untreated. PVNS can recur in patients even after treatment. [from ORDO]

Testicular germ cell tumors (TGCTs) affect 1 in 500 men and are the most common cancer in males aged 15 to 40 in western European populations. The incidence of TGCT rose dramatically during the 20th century. Known risk factors for TGCT include a history of undescended testis (UDT), testicular dysgenesis, infertility, previously diagnosed TGCT, and a family history of the disease. Brothers of men with TGCT have an 8- to 10-fold risk of developing TGCT, whereas the relative risk to fathers and sons is 4-fold. This familial relative risk is much higher than that for most other types of cancer (summary by Rapley et al., 2000). Genetic Heterogeneity of Testicular Germ Cell Tumors A locus for testicular germ cell tumors (TGCT1; 300228) has been identified on chromosome Xq27. [from OMIM]

A non-seminomatous malignant germ cell tumor characterized by the presence of large germ cells with abundant cytoplasm resembling epithelial cells, geographic necrosis, high mitotic activity, and pseudoglandular and pseudopapillary structures formation. It can arise from the testis, ovary, and extragonadal sites (central nervous system and mediastinum). [from NCI]

A malignant germ cell tumor of the central nervous system composed of large cells that proliferate in cohesive nests and sheets. In rare occasions, tumor cells may replicate the structure of the early embryo, forming ""embryoid bodies"" replete with germ discs and miniature amniotic cavities. Additional morphologic characteristics include enlarged nucleoli, abundant clear to somewhat violet-hued cytoplasm, a high mitotic rate and zones of coagulative necrosis. (Adapted from WHO) [from NCI]

An embryonal carcinoma arising from the ovary. Signs and symptoms include the presence of an abdominal mass and abdominal pain. [from NCI]

X-linked congenital generalized hypertrichosis is an extremely rare type of hypertrichosis lanuginosa congenita, a congenital skin disease, which is characterized by hair overgrowth on the entire body in males, and mild and asymmetric hair overgrowth in females. It is associated with a mild facial dysmorphism (anterverted nostrils, moderate prognathism), and, in a kindred, it was also associated with dental anomalies and deafness. [from ORDO]

A cytogenetic abnormality that refers to the allelic loss of all or part of the short arm of chromosome 12. [from MONDO]

A non-neoplastic or neoplastic disorder affecting the testis. Representative examples include torsion, infarction, germ cell tumor, sex cord-stromal tumor, lymphoma, and leukemia. [from NCI]

The presence of a neoplasm of the testis. [from HPO]

An epithelioid sarcoma involving the extremities. It usually presents as nodular masses in the dermis and subcutaneous tissues or in the tendons and fascia. It frequently recurs and metastasizes to other anatomic sites. The most common sites of metastasis are the lungs, lymph nodes, bones, and brain. [from NCI]

A malignant germ cell tumor that arises from the testis. It predominantly affects young men. Seminoma is the most frequently seen malignant testicular germ cell tumor, followed by embryonal carcinoma and yolk sac tumor. [from NCI]

A classification of testicular cancers that arise in specialized sex cells called germ cells. Nonseminomas include embryonal carcinoma, teratoma, choriocarcinoma, and yolk sac tumor. [from NCI]

A form of testicular germ cell tumor occurring in the third decade of life with a usually painless unilateral mass in the scrotum or, in some cases, with gynaecomastia and/or back and flack pain. The clinical course is more aggressive than testicular seminomatous germ cell tumors with rapid involvement of blood vessels and a poorer prognosis. Histologically, the tumour can be either undifferentiated (embryonal carcinoma), differentiated (teratoma, yolk sac tumor, choriocarcinoma), or can consist of a mixture of seminomatous and nonseminomatous components. [from ORDO]