A germinoma is a type of germ-cell tumor, which is not differentiated upon examination. It may be benign or

malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

Cause

Germinomas are thought to originate from an error of development, when certain primordial germ cells fail to migrate properly. Germinomas lack histologic differentiation, whereas nongerminomatous germ-cell tumors display a variety of differentiation. Like other germ-cell tumors, germinomas can undergo malignant transformation.

Histology

The tumor is uniform in appearance, consisting of large, round cells with vesicular nuclei and clear or finely granular

cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ...

that is eosinophilic. On gross examination, the external surface is smooth and bosselated (knobby), and the interior is soft, fleshy, and either cream-coloured, gray, pink, or tan. Microscopic examination typically reveals uniform cells that resemble primordial germ cells. Typically, the stroma contains

lymphocyte A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), an ...

s, and about 20% of patients have sarcoid-like granulomas.

Diagnosis

Metastasis has been noted in about 22% of cases at time of diagnosis. Males are roughly twice as commonly affected in developing germinomas. They are most commonly diagnosed between the ages of 10 and 21. Often, serum and spinal fluid tumor markers of alpha-fetoprotein and beta-HCG are tested. Pure germinomas are not associated with these markers. Nongerminomatous germ-cell tumors may be associated with increased markers such as alpha-fetoprotein with yolk sac tumors, as well as embryonic cell carcinomas and immature teratomas and beta-HCG, which occur in choriocarcinomas. In one to 15% of germinomas, a low level of beta-HCG may be produced. Although controversial, HCG-secreting germinomas may be more aggressive than nonsecreting ones.

Classification

The term "germinoma" most often refers to a

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

in the

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

that has a

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at large ...

identical to two other tumors, dysgerminoma in the

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

and seminoma in the testis. Since 1994, MeSH has defined germinoma as "a

neoplasm of the germinal tissue of the

gonad A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gon ...

s, mediastinum, or pineal region" and within its scope included both dysgerminoma and seminoma. Collectively, these are the seminomatous or germinomatous tumors.

Locations

Ovary (dysgerminoma) and testis (seminoma)

Dysgerminoma is the most common type of

germ-cell ovarian cancer. Dysgerminoma usually occurs in

adolescence Adolescence () is a transitional stage of human Developmental biology, physical and psychological Human development (biology), development that generally occurs during the period from puberty to adulthood (typically corresponding to the age o ...

and early adult life; about 5% occur in prepubertal children. Dysgerminoma is extremely rare after age 50. It occurs in both ovaries in 10% of patients and, in a further 10%, a microscopic tumor is in the other ovary.

Seminoma A seminoma is a germ cell tumor of the testicle or, more rarely, the mediastinum or other extra-gonadal locations. It is a Malignancy, malignant neoplasm and is one of the most treatable and curable cancers, with a survival rate above 95% if di ...

is the second-most common testicular cancer; the most common is mixed, which may contain seminoma. Abnormal gonads (due to gonadal dysgenesis and

androgen insensitivity syndrome Androgen insensitivity syndrome (AIS) is a condition involving the inability to respond to androgens, typically due to androgen receptor dysfunction. It affects 1 in 20,000 to 64,000 XY (karyotype, karyotypically male) births. The condition result ...

) have a high risk of developing a dysgerminoma. Most dysgerminomas are associated with elevated serum lactic dehydrogenase, which is sometimes used as a tumor marker. Metastases are most often present in the lymph nodes.

Intracranial germinoma

Intracranial germinoma occurs in 0.7 per million children. As with other germ-cell tumors (GCTs) occurring outside the gonads, the most common location of intracranial germinoma is on or near the midline, often in the pineal or suprasellar areas; in 5-10% of patients with germinoma in either area, the tumor is in both areas. Like other GCTs, germinomas can occur in other parts of the brain. Within the

, this tumor is most common in the hypothalamic or hypophyseal regions. In the

thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...

and basal ganglia, germinoma is the most common GCT. The diagnosis of an intracranial germinoma usually is based on biopsy, as the features on neuroimaging appear similar to other tumors. Cytology of the cerebrospinal fluid often is studied to detect metastasis into the spine. This is important for staging and radiotherapy planning. Intracranial germinomas have a reported 90% survival to five years after diagnosis. Near total resection does not seem to influence the cure rate, so gross total resection is not necessary and can increase the risk of complications from surgery. The best results have been reported from craniospinal radiation with local tumor boost of greater than 4,000 centigray (cGy).

Treatment

Germinomas, like several other types of GCTs, are sensitive to both

chemotherapy Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (list of chemotherapeutic agents, chemotherapeutic agents or alkylating agents) in a standard chemotherapy re ...

and

radiotherapy Radiation therapy or radiotherapy (RT, RTx, or XRT) is a treatment using ionizing radiation, generally provided as part of cancer therapy to either kill or control the growth of malignant cells. It is normally delivered by a linear particle ...

. For this reason, treatment with these methods can offer excellent chances of long-term survival, even cure.

Prognosis

Although chemotherapy can shrink germinomas, it is not generally recommended alone unless radiation has contraindications. In a study in the early 1990s, carboplatinum, etoposide, and bleomycin were given to 45 germinoma patients, and about half the patients relapsed. Most of these relapsed patients were then recovered with radiation or additional chemotherapy.

References

External links

{{Tumor markers, state=collapsed Rare cancers Pediatrics Gynaecological cancer Male genital neoplasia Germ cell neoplasia