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sex cord-stromal tumors

Thursday 14 January 2010

Sex Cord-Stromal Tumors; ovarian sex cord-stromal tumors; Sex cord–gonadal stromal tumour

WKP

Definition : Sex cord–gonadal stromal tumour (or sex cord–stromal tumour) is a group of tumors derived from the stromal component of the ovary and testis, which comprises the granulosa, thecal cells and fibrocytes.

In contrast, the epithelial cells originate from the outer epithelial lining surrounding the gonad while the germ cell tumors arise from the precursor cells of the gametes, hence the name germ cell.

In humans, this group accounts for 8% of ovarian cancers and under 5% of testicular cancers.

Localization

- ovarian sex cord-stromal tumors
- testicular sex cord-stromal tumors

Definition

Sex cord-stromal tumors are groups of tumors composed of granulosa cells, theca cells, Sertoli cells, Leydig cells, and fibroblasts of stromal origin, singly or in various combinations.

According to the WHO, sex cord-stromal tumors are classified into the following categories:

- ovarian granulosa-stromal cell tumors
- ovarian granulosa cell tumor group

  • adult-type ovarian granulosa cell tumor
  • juvenile-type ovarian granulosa cell tumor

- ovarian thecoma-fibroma group
- ovarian thecoma , not otherwise specified

  • typical ovarian thecoma
  • luteinized ovarian thecoma

- ovarian fibroma

- Stromal tumor with minor sex cord elements
- Sclerosing stromal tumor
- Signet ring cell stromal tumor
- Unclassified (fibrothecoma)
- Sertoli-stromal cell tumors
- Sertoli-Leydig cell tumors group (androblastomas)
- Well differentiated
- Of intermediate differentiation

- Variant with heterologous elements
- Poorly differentiated (sarcomatoid)
- Variant with heterologous elements
Retiform
Variant with heterologous elements

- Sertoli cell tumors
- Stromal-Leydig cell tumor
- Sex cord-stromal tumors of mixed or unclassified cell types
- Sex cord tumor with annular tubules
- Gynandroblastoma
- Sex cord-stromal tumor, unclassified
- Steroid cell tumors
- Stromal luteoma
- Leydig cell tumor group
- Hilus cell tumor
- Leydig cell tumors nonhilar type
- Leydig cell tumors, not otherwise specified
- Steroid cell tumors, not otherwise specified
- Well differentiated
- Malignant

Epidemiology

Sex cord-stromal tumors account for approximately 8% of all ovarian tumors.

Immunochemistry

Markers with variable specificity for sex cord-stromal lineage:

- inhibin
- calretinin
- MART-1/melan-A
- CD99
- steroidogenic factor 1 (SF1, SF-1, adrenal 4-binding protein)
- WT1

Types of ovarian sex cord stromal tumors:

- adult granulosa cell tumor
- Sertoli cell tumor
- Sertoli-Leydig cell tumor
- steroid cell tumor
- fibroma/fibrothecoma

All cases in each type of sex cord-stromal tumor express SF-1.

Inhibin and calretinin are expressed in all groups of tumors but with a lesser frequency (56% to 100% and 36% to 100% of cases, respectively).

All types of tumors except steroid cell tumor express WT1.

Fibroma/fibrothecoma is the only type of tumor that did not express CD99.

The only tumor groups that show expression of MART-1 are Sertoli-Leydig cell tumor (restricted to the Leydig cell component) and steroid cell tumor (94% and 96% of cases, respectively).

The type of sex cord-stromal tumor that was least frequently positive for several of the different markers studied was fibroma/fibrothecoma.

Among all tumor groups combined, inhibin and WT1 are the 2 markers showing the most diffuse expression.

Likewise, the single marker showing the most optimal combination of diffuse and strong staining (immunohistochemical composite score: possible range, 1 to 12) varies between tumors (19033865):
- adult granulosa cell tumor-inhibin (score 10.0);
- Sertoli cell tumor-WT1 (score 10.8);
- Sertoli-Leydig cell tumor (Sertoli cell component)-WT1 (score 10.4);
- steroid cell tumor-inhibin (score 11.2);
- fibroma/fibrothecoma-WT1 (score 8.9).

Most immunohistochemical sex cord-stromal markers have sufficient sensitivity for sex cord-stromal lineage.

Although each of the different types of sex cord-stromal tumors has a slightly unique immunoprofile in terms of frequency and extent of expression, these differences are relatively minor for most types of tumors with certain exceptions (eg, WT1 is not diagnostically useful in steroid cell tumor; CD99 is not diagnostically useful in fibroma/fibrothecoma; the only sex cord-stromal tumor for which MART-1 is diagnostically useful is steroid cell tumor; inhibin and calretinin are less diagnostically useful in fibroma/fibrothecoma than in the other types of tumors, but expression in fibrothecoma was higher than in fibroma).

SF-1 is the most sensitive sex cord-stromal marker among the most common types of sex cord-stromal tumors.

The most informative sex cord-stromal markers to be used for the distinction from nonsex cord-stromal tumors are inhibin, calretinin, SF-1, and WT1 (the exact number of markers to be used should be based on the degree of difficulty of the case and level of experience of the pathologist).

However, the utility of immunohistochemistry for the diagnosis of fibroma/fibrothecoma is somewhat limited.

See also

- ovarian tumors
- sex cord stromal tumors

References

- Identification of the most sensitive and robust immunohistochemical markers in different categories of ovarian sex cord-stromal tumors. Zhao C, Vinh TN, McManus K, Dabbs D, Barner R, Vang R. Am J Surg Pathol. 2009 Mar;33(3):354-66. PMID: 19033865