Germ cell tumors are a group of neoplasms that develop from the primary germ cells of the gonads. They can occur both in the testicles or ovaries, and extragonadally. The manifestations depend on the localization. With superficially located neoplasms, visible deformation is observed, with nodes in the ovary, pain, dysuria and menstrual cycle disorders are noted. With disease of the mediastinum, shortness of breath occurs, with intracranial lesions, focal and cerebral symptoms are revealed. The diagnosis is made taking into account the symptoms, X-ray data, ultrasound, CT, MRI and other techniques. Treatment – surgery, chemotherapy, radiotherapy.
General information
Germ cell tumors are a group of benign and malignant neoplasms arising from primary germ cells, which are the precursors of the testicles and ovaries. Due to the migration of such cells during embryogenesis, pathology can develop outside the gonads: in the mediastinum, sacrococcygeal region, brain, retroperitoneal space and other anatomical zones. Primary extragonadal neoplasms account for 5% of the total number of germ cell tumors.
The ratio between the number of extra- and intragonadal neoplasias changes with age. In young children, lesions of the sacrococcygeal zone predominate, as they grow older, the frequency of neoplasms in the testicles and ovaries increases. Disease of all localizations account for 3% of the total number of oncological diseases in children, germinogenic neoplasms of the ovaries – 2-3% of all malignant neoplasms of the ovaries in women, germinogenic lesions of the testicle – 95% of the total number of testicular tumors in men. The treatment is carried out by specialists in the field of oncology, gynecology, urology and other fields of medicine.
Causes
Germ cell tumors arise from germ germ cells, which are formed in the yolk sac at the initial stages of embryogenesis, and then migrate through the embryo’s body to the urogenital scallop. During migration, some of these cells may linger in various anatomical zones, which subsequently causes the formation of germ cell tumors of extra-gonadal localization. Normally, germinogenic cells turn into mature cells of the testicles and ovaries, however, under certain conditions, such cells can remain in their embryonic state and, under the influence of negative external and internal factors, give rise to gonadal neoplasms.
It has been established that disease are often diagnosed in patients with various genetic abnormalities, for example, Klinefelter syndrome. A hereditary predisposition is revealed, which may or may not be combined with chromosomal disorders. A characteristic feature of germ cell tumors is an isochromosome resulting from the doubling of the short arm and the loss of the long arm by the 12th chromosome, however, other chromosomal abnormalities may be detected. There is a frequent combination of germ cell tumors with other oncological lesions, including leukemias, lymphomas and neuroblastomas. The probability of germinogenic testicular neoplasia increases with cryptorchidism.
The histological type of germ cell tumors depends on age. Benign teratomas are more often diagnosed in newborns, neoplasia of the yolk sac is detected in young children, malignant teratomas and dysgerminomas are detected in adolescents, seminomas in adults, etc. The factors contributing to the activation of growth and malignant transformation of germ germ cells have not yet been clarified. It is assumed that the impetus for the development of germ cell tumors in children may be chronic diseases of the mother or the mother taking certain medications.
Classification
There are several classifications of germinogenic neoplasia, compiled taking into account the morphological characteristics of the neoplasm, location and features of the course of the disease. According to the WHO classification, the following morphological types of germ cell tumors are distinguished:
- Germinoma (dysgerminoma, seminoma)
- Embryonic cancer
- Neoplasia of the yolk sac
- Spermatocyte seminoma
- Chorioncarcinoma
- Polyembryoma
- Teratoma, including mature, immature, with a certain orientation of tissue differentiation (carcinoid, ovarian struma), malignant.
- Mixed germinogenic tumor, which is a combination of several histological variants of neoplasia.
- The source of germin is the primary germ cells, the source of the remaining neoplasms are the elements of the environment of such cells.
Taking into account localization, gonadal and extragonadal germ cell tumors are distinguished. Extragonadal neoplasia is divided into extracranial and intracranial. In addition, malignant and benign germinogenic neoplasia, as well as primary and recurrent neoplasms, are isolated.
Symptoms
The features of the course of the disease are determined by the localization, size and degree of malignancy of neoplasia. Typical symptoms of germinogenic ovarian tumors are abdominal pain of varying intensity in combination with menstrual disorders. In children, the latter sign is absent, which causes a lack of alertness regarding the lesion of the internal genitalia at the initial stages of the disease. With the progression of germ cell tumors, these symptoms are joined by an increase in the abdomen and urination disorders. During palpation at the initial stages, a rounded, moderately mobile node with clear contours is determined. Subsequently, the node increases in size, there is an increase and deformation of the abdomen. In the later stages, ascites and disorders of the functions of various organs due to distant metastasis are detected.
Germ cell tumors are manifested by an increase in the corresponding half of the scrotum, a feeling of heaviness and bursting. Soreness or hypersensitivity of the affected area is noted by about 25% of patients. Palpation will determine the tumor-like formation or uniform enlargement of the testicle. In 5-10% of patients with germ cell tumors, hydrocele is detected, in 10-14% – gynecomastia. With lymphogenic and distant metastasis, an increase in inguinal lymph nodes, neurological disorders, bone pain, back pain and abdominal pain are possible.
Germ cell tumors of the mediastinum, as a rule, are localized behind the sternum. Benign neoplasms (teratomas) are characterized by slow growth, malignant neoplasms (teratoblastomas and other neoplasias) are characterized by aggressive spread and rapid germination of nearby organs. The most common manifestations of germ cell tumors are shortness of breath, cough and chest pain. When the superior vena cava is compressed, there is noise in the head, headache, tinnitus, disorders of consciousness, drowsiness and visual disturbances. Convulsions are possible. In malignant germ cell tumors, hyperthermia, fever, weight loss and dysfunction of various organs due to germination or distant metastasis are observed.
Retroperitoneal form are asymptomatic for a long time. They may manifest dyspepsia, abdominal pain, dysuria, shortness of breath, edema and varicose veins of the lower extremities. With malignant lesions in the late stages, symptoms of cancer intoxication are revealed. Germ cell tumors of the sacrococcygeal zone are usually diagnosed in young children and proceed benign. With large neoplasias, pain and weakness in the lower extremities, defecation disorders and dysuria are observed. Bleeding and necrosis are possible. Intracranial germ cell tumors are more often localized in the area of the epiphysis, sometimes in the hypothalamus or pituitary gland. They are manifested by headache, nausea, vomiting and disorders of the movements of the eyeballs.
Diagnosis and treatment
The diagnosis is made taking into account complaints, the results of a physical examination and additional research data. Depending on the location of neoplasia, a rectal examination or vaginal examination may be required. Patients are prescribed ultrasound, CT and MRI of the affected area. The content of alpha-fetoprotein in the blood serum is evaluated. In malignant germ cell tumors, chest x-ray, ultrasound and MRI of abdominal organs, ultrasound of lymph nodes, scintigraphy of skeletal bones and other diagnostic procedures are performed to exclude lymphogenic and distant metastases. The type of neoplasia is determined taking into account the data of histological examination.
Benign germ cell tumors are excised, combined treatment is prescribed for malignant neoplasms, including surgery (for resectable neoplasms), chemotherapy and radiotherapy. In the presence of single metastases in the lungs and liver, their surgical removal is possible. With low efficacy of aggressive semin therapy, in some cases, high-dose radiotherapy is carried out with subsequent bone marrow transplantation, however, the effectiveness of this method in germ cell tumors is still difficult to assess due to insufficient number of observations.
The prognosis for benign neoplasia is usually favorable. Malignant germ cell tumors were previously considered as prognostically unfavorable, but the use of combination therapy allowed to increase the five-year survival rate in this pathology to 60-90%. Survival is affected by the type and prevalence of germ cell tumors, the radicality of surgical intervention, the presence or absence of metastases.