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ovarian dysgerminoma

Thursday 22 December 2005

Definition: a primitive germ cell tumor, similar to testicular seminoma. A dysgerminoma is a type of germ cell tumor; it usually is malignant and usually occurs in the ovary.

Dysgerminoma (seminoma) has fibrous septae infiltrated by lymphocytes. It also tends to arise out of intratubular germ cell neoplasia. If syncytiotrophoblast is present, it may have elevated hCG.

Digital cases

- JRC:258 : Ovarian dysgerminoma

Images

- ovarian dysgerminoma with "indian file" pattern

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 body.

Dysgerminoma accounts for less than 1% of ovarian tumors overall.

Dysgerminoma usually occurs in adolescence and early adult life; about 5% occur in pre-pubertal children. Dysgerminoma is extremely rare after age 50.

Dysgerminoma occurs in both ovaries in 10% of patients and, in a further 10%, there is microscopic tumor in the other ovary.

Abnormal gonads (due to gonadal dysgenesis and androgen insensitivity syndrome) have a high risk of developing a dysgerminoma.

Most dysgerminomas are associated with elevated serum lactic dehydrogenase (LDH), which is sometimes used as a tumor marker.

Synopsis

- 90% are apparently unilateral, but occult foci of dysgerminoma can be detected by biopsy of the contralateral ovary in 10% of cases
- monotonous proliferation of primitive germ cells
- connective tissue septa containing variable amounts of chronic inflammatory cells

Epidemiology

- Usually teenage girls or young women.
- 2% ovarian neoplasms.
- 1/2 of malignant germ cell neoplasms.
- Gonadal dysgenesis may be setting for some.

Clinical

- If confined to the ovary and @<@10 cms. cure can be achieved with surgery alone
- Exquisitely radiosensitive if metastatic.
- For more information on prognosis and treatment, consult the NCI web site.

They are exceptionally associated with hypercalcemia.

Metastases are most often present in the lymph nodes.

Macroscopy

- Usually unilateral and confined to ovary.
- Homogenous tan, fleshy lesion.
- Usually without hemorrhage or necrosis.

On gross examination, dysgerminomas present with a smooth, bosselated (knobby) external surface, and is soft, fleshy and either cream-coloured, gray, pink or tan when cut.

Microscopy

- Identical to seminoma.
- Cells in nests separated by delicate fibrovascular septae.
- Septae may contain lymphocytes or even granuloma.
- Cells have round to oval nuclei, relatively clear cytoplasm, and well defined cell borders.
- The neoplastic cells have large nuclei with mild irregularity of the nuclear outline.
- Nucleoli can be seen.
- The cells have mostly clear cytoplasm.
- The cell borders are well demarcated.

Microscopic examination typically reveals uniform cells that resemble primordial germ cells. Typically, the stroma contains lymphocytes and about 20% of patients have sarcoid-like granulomas.

Immunohistochemistry

- vimentin +
- PLAP + (placental-like alkaline phosphatase)
- CD117 (c-kit) +
- inconstant + to - : cytokeratins, desmin, GFAP, CEA and S-100 protein

Etiology and evolution

- the vast majority have no precursor lesion
- may arise from gonadoblastoma
- may be a precursor to other primitive germ cell tumors

Associations

- Apert syndrome with germline FGFR2 mutations (17243131)

  • Apert syndrome is an autosomal dominant disorder that results from gain-of-function mutations in the FGFR2 gene.
  • FGFR2 also has been shown to be amplified in stomach and breast cancers.

Gene mutations

- c-kit (CD117, KIT)

  • Ovarian dysgerminomas are characterised by frequent KIT mutations and abundant expression of pluripotency markers. (17274819)

Other localizations

- mediastinal dysgerminoma

Treatment

Dysgerminomas, like other seminomatous germ cell tumors, are very sensitive to both chemotherapy and radiotherapy.

For this reason, with treatment patients’ chances of long term survival, even cure, is excellent.

See also

- germinal tumors

  • seminoma and dysgerminoma

- ovarian germ cell tumours (OGCTs)

References

- Ovarian dysgerminoma and Apert syndrome. Rouzier C, Soler C, Hofman P, Brennetot C, Bieth E, Pedeutour F. Pediatr Blood Cancer. 2008 Mar;50(3):696-8. PMID: 17243131

- Ovarian dysgerminomas are characterised by frequent KIT mutations and abundant expression of pluripotency markers. Hoei-Hansen CE, Kraggerud SM, Abeler VM, Kaern J, Rajpert-De Meyts E, Lothe RA. Mol Cancer. 2007 Feb 2;6:12. PMID: 17274819 (Free)