Жыныс жасушалары ісігі: түрлері, диагнозы және емдеуі

Germ cell tumor (GCT) is a neoplasm derived from the primordial germ cells. Germ cell tumors can be cancerous or benign. Germ cells normally occur inside the gonads (ovary and testis). GCTs that originate outside the gonads may be birth defects resulting from errors during development of the embryo.

GCTs are classified by their histology, regardless of location in the body. However, as more information about the genetics of these tumors become available, they may be classified based on specific gene mutations that characterize specific tumors. They are broadly divided in two classes:
The germinomatous or seminomatous germ cell tumors (GGCT, SGCT) include only germinoma and its synonyms dysgerminoma and seminoma. The nongerminomatous or nonseminomatous germ cell tumors (NGGCT, NSGCT) include all other germ cell tumors, pure and mixed. The two classes reflect an important clinical difference. Compared with germinomatous tumors, nongerminomatous tumors tend to grow faster, have an earlier mean age at time of diagnosis (around 25 years versus 35 years, in the case of testicular cancers), and have a lower five year survival rate. The survival rate for germinomatous tumors is higher in part because these tumors are very sensitive to radiation, and they also respond well to chemotherapy. The prognosis for nongerminomatous tumours has improved dramatically, however, due to the use of platinum based chemotherapy regimens.

Some investigators suggest that this distribution arises as a consequence of abnormal migration of germ cells during embryogenesis. Others hypothesize a widespread distribution of germ cells to multiple sites during normal embryogenesis, with these cells conveying genetic information or providing regulatory functions at somatic sites. Extragonadal GCTs were thought initially to be isolated metastases from an undetected primary tumor in a gonad, but many germ cell tumors are now known to be congenital and originate outside the gonads. The most notable of these is sacrococcygeal teratoma, the single most common tumor diagnosed in babies at birth. Of all anterior mediastinal tumors, 15–20% are GCTs of which about 50% are benign teratomas. Ovarian teratomas may be associated with anti NMDA receptor encephalitis.

Women with benign GCTs such as mature teratomas (dermoid cysts) are cured by ovarian cystectomy or oophorectomy. If the patient is in her reproductive years, an alternative is unilateral salpingoophorectomy, while the uterus, the ovary, and the fallopian tube on the opposite side can be left behind. This is not an option when the cancer is in both ovaries. If the patient has finished having children, the surgery involves complete staging, including salpingoophorectomy on both sides, as well as hysterectomy. The chemotherapy regimen most commonly used in GCTs is called PEB (or BEP), and consists of bleomycin, etoposide, and a platinum based antineoplastic (cisplatin). Targeted treatments, such as immunotherapy, hormonal therapy and kinase inhibitors, are being evaluated for tumors that do not respond to chemotherapy.

The 1997 International Germ Cell Consensus Classification is a tool for estimating the risk of relapse after treatment of malignant germ cell tumor. A small study of ovarian tumors in girls reports a correlation between cystic and benign tumors, and conversely, solid and malignant tumors. Because the cystic extent of a tumor can be estimated by ultrasound, MRI, or CT scan before surgery, this permits selection of the most appropriate surgical plan to minimize risk of spillage of a malignant tumor. Access to appropriate treatment has a large effect on outcome. A 1993 study of outcomes in Scotland found that for 454 men with nonseminomatous (nongerminomatous) GCTs diagnosed between 1975 and 1989, five year survival increased over time and with earlier diagnosis. Adjusting for these and other factors, survival was 60% higher for men treated in a cancer unit that treated the majority of these men, though the unit treated more men with the worst prognosis. Choriocarcinoma of the testicles has the worst prognosis of all germ cell cancers.