Seminoma
Encyclopedia
Seminoma is a germ cell tumor
(cancer) of the testis. It is one of the most treatable and curable cancers, with survival >95% in the early stages. Treatment usually requires removal of one testis, but this does not affect fertility or other sexual functioning.
Seminoma originates in the germinal epithelium
of the seminiferous tubules. About half of germ cell tumors of the testis are seminomas.
; however, in up to 11 percent of cases, there may be no mass able to be felt, or there may be testicular atrophy
. Testicular pain is reported in up to one fifth of cases. Low back pain may occur after metastasis
to the retroperitoneum
.
Some cases of seminoma can present as a primary tumour outside the testis. In the ovary
, the tumor is called a dysgerminoma
, and in non-gonad
al sites, particularly the central nervous system
, it is called a germinoma
.
s may detect the presence of placental alkaline phosphatase
(PLAP) in fifty percent of cases. Human chorionic gonadotropin
(hCG) may be elevated in some cases, but this correlates more to the presence of trophoblast
cells within the tumour than to the stage of the tumour. Serum alpha fetoprotein is not elevated in classical seminoma.
The cut surface of the tumour is fleshy and lobulated, and varies in colour from cream to tan to pink. The tumour tends to bulge from the cut surface, and small areas of hemorrhage may be seen. These areas of hemorrhage usually correspond to trophoblastic cell clusters within the tumour.
Microscopic examination shows that seminomas are usually composed of either a sheet-like or lobular pattern of cells with a fibrous stroma
l network. The fibrous septa almost always contain focal lymphocyte
inclusions, and granuloma
s are sometimes seen. The tumour cells themselves typically have abundant clear to pale pink cytoplasm containing abundant glycogen
, which is demonstrable with a periodic acid-Schiff
(PAS) stain. The nuclei are prominent and usually contain one or two large nucleoli, and have prominent nuclear membranes. Foci of syncytiotrophoblast
ic cells may be present in varied amounts. The adjacent testicular tissue commonly shows intratubular germ cell neoplasia
, and may also show variable spermatocytic maturation arrest.
POU2AF1
and PROM1 have been proposed as possible markers.
. The management of childhood seminoma is similar to that of adult seminoma. Inguinal orchiectomy
is required in almost all cases.
5-year survival rate is approximately 90% as of 2008.
A study of 31 men with metastatic germ cell tumor
of the testis and delayed orchidectomy found that in men with pure seminoma, chemotherapy alone was sufficient to eliminate the cancer from the testis. The authors of this study suggest that treatment of pure seminoma may not require orchidectomy. Event-free survival of this group of men at an average followup of 4 years was 81.8%.
s are not considered a subtype
of seminoma and unlike other germ cell tumours do not arise from intratubular germ cell neoplasia
.
Germ cell tumor
A germ cell tumor is a neoplasm derived from germ cells. Germ cell tumors can be cancerous or non-cancerous tumors. Germ cells normally occur inside the gonads...
(cancer) of the testis. It is one of the most treatable and curable cancers, with survival >95% in the early stages. Treatment usually requires removal of one testis, but this does not affect fertility or other sexual functioning.
Seminoma originates in the germinal epithelium
Germinal epithelium (male)
The germinal epithelium is the innermost layer of the testicle.Germinal epithelium is also known as the wall of the seminiferous tubule within the testes. It is cells in the epithelium are connected via tight junctions....
of the seminiferous tubules. About half of germ cell tumors of the testis are seminomas.
Presentation
The average age of diagnosis is 40 years. This is about 5 to 10 years older than men with other germ cell tumors of the testes. In most cases, they produce masses that are readily felt on testicular self-examinationTesticular self-examination
Because testicular cancer is a significant killer of teenage boys and younger men , doctors recommend monthly self-examination.Men from puberty onwards should examine their testes after a hot shower or bath, when the scrotum is looser...
; however, in up to 11 percent of cases, there may be no mass able to be felt, or there may be testicular atrophy
Testicular atrophy
Testicular atrophy is a medical condition in which the male reproductive organs diminish in size and may be accompanied by loss of function. This does not refer to temporary changes, such as those brought on by cold.Some medications can cause testicular atrophy...
. Testicular pain is reported in up to one fifth of cases. Low back pain may occur after metastasis
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
to the retroperitoneum
Retroperitoneum
The retroperitoneal space is the anatomical space in the abdominal cavity behind the peritoneum. It has no specific delineating anatomical structures...
.
Some cases of seminoma can present as a primary tumour outside the testis. In the ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
, the tumor is called a dysgerminoma
Dysgerminoma
A dysgerminoma is a type of germ cell tumor; it usually is malignant and usually occurs in the ovary.A tumor of the identical histology but not occurring in the ovary may be described by an alternate name: seminoma in the testis or germinoma in the central nervous system or other parts of the...
, and in non-gonad
Gonad
The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes...
al sites, particularly the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
, it is called a germinoma
Germinoma
A germinoma is a type of germ cell tumor which is not differentiated upon examination. It may be benign or malignant.-Classification:The term germinoma most often has referred to a tumor in the brain that has a histology identical to two other tumors: dysgerminoma in the ovary and seminoma in the...
.
Diagnosis
Blood testBlood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....
s may detect the presence of placental alkaline phosphatase
Alkaline phosphatase
Alkaline phosphatase is a hydrolase enzyme responsible for removing phosphate groups from many types of molecules, including nucleotides, proteins, and alkaloids. The process of removing the phosphate group is called dephosphorylation...
(PLAP) in fifty percent of cases. Human chorionic gonadotropin
Human chorionic gonadotropin
Human chorionic gonadotropin or human chorionic gonadotrophin is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast .. Some tumors make this hormone; measured elevated levels when the patient is not...
(hCG) may be elevated in some cases, but this correlates more to the presence of trophoblast
Trophoblast
Trophoblasts are cells forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. They are formed during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg...
cells within the tumour than to the stage of the tumour. Serum alpha fetoprotein is not elevated in classical seminoma.
The cut surface of the tumour is fleshy and lobulated, and varies in colour from cream to tan to pink. The tumour tends to bulge from the cut surface, and small areas of hemorrhage may be seen. These areas of hemorrhage usually correspond to trophoblastic cell clusters within the tumour.
Microscopic examination shows that seminomas are usually composed of either a sheet-like or lobular pattern of cells with a fibrous stroma
Stroma (animal tissue)
In animal tissue, stroma refers to the connective, supportive framework of a biological cell, tissue, or organ.The stroma in animal tissue is contrasted with the parenchyma.Examples include:* Stroma of iris...
l network. The fibrous septa almost always contain focal lymphocyte
Lymphocyte
A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...
inclusions, and granuloma
Granuloma
Granuloma is a medical term for a tiny collection of immune cells known as macrophages. Granulomas form when the immune system attempts to wall off substances that it perceives as foreign but is unable to eliminate. Such substances include infectious organisms such as bacteria and fungi as well as...
s are sometimes seen. The tumour cells themselves typically have abundant clear to pale pink cytoplasm containing abundant glycogen
Glycogen
Glycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...
, which is demonstrable with a periodic acid-Schiff
Periodic acid-Schiff
Periodic acid-Schiff is a staining method used to detect glycogen and other polysaccharides in tissues. The reaction of periodic acid oxidizes the diol functional groups in glucose and other sugars, creating aldehydes that react with the Schiff reagent to give a purple-magenta color...
(PAS) stain. The nuclei are prominent and usually contain one or two large nucleoli, and have prominent nuclear membranes. Foci of syncytiotrophoblast
Syncytiotrophoblast
Syncytiotrophoblast is the epithelial covering of the placenta villous tree. It is a unique tissue in that it is a multi-nucleated, terminally differentiated syncytium, extending to 13m^2...
ic cells may be present in varied amounts. The adjacent testicular tissue commonly shows intratubular germ cell neoplasia
Intratubular germ cell neoplasia
Intratubular germ cell neoplasia, abbreviated ITGCN or IGCN and also known as testicular intratubular germ cell neoplasia and intratubular germ cell neoplasia of the testis, is considered a precursor lesion for many types of testicular germ cell tumors.The common, unspecified variant of the entity...
, and may also show variable spermatocytic maturation arrest.
POU2AF1
POU2AF1
POU domain class 2-associating factor 1 is a protein that in humans is encoded by the POU2AF1 gene.-Interactions:POU2AF1 has been shown to interact with POU2F1 and SIAH1.-Further reading:...
and PROM1 have been proposed as possible markers.
Treatment
In recent years, these tumors have been shown to have dramatic sensitivity to both radiotherapy and cytotoxic chemotherapyChemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
. The management of childhood seminoma is similar to that of adult seminoma. Inguinal orchiectomy
Inguinal orchiectomy
Inguinal orchiectomy is a surgical procedure to remove a testicle and the full spermatic cord through an incision in the abdomen. Orchiectomy is one form of castration. The procedure is generally performed by a urologist. Often it is performed as same-day surgery, with the patient returning home...
is required in almost all cases.
5-year survival rate is approximately 90% as of 2008.
A study of 31 men with metastatic germ cell tumor
Germ cell tumor
A germ cell tumor is a neoplasm derived from germ cells. Germ cell tumors can be cancerous or non-cancerous tumors. Germ cells normally occur inside the gonads...
of the testis and delayed orchidectomy found that in men with pure seminoma, chemotherapy alone was sufficient to eliminate the cancer from the testis. The authors of this study suggest that treatment of pure seminoma may not require orchidectomy. Event-free survival of this group of men at an average followup of 4 years was 81.8%.
Relation to spermatocytic seminoma
Spermatocytic seminomaSpermatocytic seminoma
Spermatocytic seminoma is a neoplasm of the testis , and classified as a germ cell tumour.The name of the tumour comes from the similarity between the small cells of the tumour and secondary spermatocytes.-Relation to seminoma:Spermatocytic seminoma is not considered a subtype of seminoma and,...
s are not considered a subtype
Subtype
In programming language theory, subtyping or subtype polymorphism is a form of type polymorphism in which a subtype is a datatype that is related to another datatype by some notion of substitutability, meaning that program constructs, typically subroutines or functions, written to operate on...
of seminoma and unlike other germ cell tumours do not arise from intratubular germ cell neoplasia
Intratubular germ cell neoplasia
Intratubular germ cell neoplasia, abbreviated ITGCN or IGCN and also known as testicular intratubular germ cell neoplasia and intratubular germ cell neoplasia of the testis, is considered a precursor lesion for many types of testicular germ cell tumors.The common, unspecified variant of the entity...
.