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granulosa-theca cell tumor

Monday 13 February 2006

granulosa-stromal cell tumors

Digital case

- JRC:18776 : Adrenal gland granulosa, theca tumor (F, 52 y/o)

Granulosa cell tumors (GCTs) are composed of granulosa cells, theca cells, and fibroblasts in varying amounts and combinations. The term "granulosa-theca cell tumor" had been applied to all tumors in which both cell types were identified, regardless of the amounts present.

Young and Scully proposed a system that required a tumor to be composed of at least 25% of the second cell type before the tumor could be designated as a true "granulosa-theca cell tumor".

Granulosa cells

Granulosa cells are capable of releasing estrogen. The hormone may produce precocious puberty in children and cause endometrial hyperplasia in women.

Granulosa cell tumors are slow growing tumors. 5-25% of these tumors exhibit malignant behavior. On the other hand, the pure thecomas are benign.

Macroscopy

Grossly, tumors can be cystic, solid, or a mixture of both. On cut section, they usually are multicystic and may contain areas of hemorrhage.

Solid tumors appear grayish if they are nonsteroidogenic or yellow if they are steroid-producing neoplasms.

Androgen-producing tumors more commonly are unilocular or solid in contrast to the multilocular tumors that make up most granulosa cell tumors (GCTs).

Microscopy

GCTs are composed of granulosa cells, theca cells, and fibroblasts in varying amounts and combinations.

The term granulosa-theca cell tumor had been applied to all tumors in which both cell types were identified, regardless of the amounts present.

Young and Scully proposed a system that required a tumor to be composed of at least 25% of the second cell type before the tumor could be designated as a true "granulosa-theca cell tumor".

Otherwise, the tumor would be designated as a granulosa cell tumor or a theca cell tumor based on the predominant cell type. This has led to some confusion in the literature because some theca cell tumors, which are essentially benign neoplasms, have been given the dual designation of granulosa-theca cell tumors, suggesting a malignant potential among this benign group of tumors.

AGCTs have multiple histomorphologies, including well-differentiated and less well-differentiated types.

The well-differentiated group is composed of microfollicular, macrofollicular, trabecular, and insular patterns.

Microfollicular is the most common pattern of all of these subtypes and contains characteristic Call-Exner bodies. These bodies consist of small rings of granulosa cells surrounding eosinophilic fluid and basement membrane material.

Macrofollicular GCTs are composed of a large cyst or collection of large cysts, each lined by a single layer of granulosa cells. Trabecular and insular patterns have cells arranged in nests and bands, with an intervening fibrothecomatous stroma found in the trabecular type.

The less well-differentiated group includes diffuse and watered-silk (moiré) or gyriform patterns. Monotonous sheets of cells arranged in no distinguishable pattern characterize the diffuse subtype.

Watered-silk and gyriform patterns have cells that often line up single-file in undulating lines.

The nuclear appearance is the same in both groups of adult GCTs. The nuclei usually are large pale ovoid or angular structures containing nuclear grooves that give them a "coffee-bean" appearance.

Usually only a small amount of cytoplasm is present, although luteinization of the tumor, characterized by larger amounts of dense cytoplasm with occasional vacuoles, sometimes can be found. Mitotic figures generally are few in number, and only mild nuclear atypia is found in most cases.

Nuclear appearance and mitotic rate often are the key elements differentiating GCTs from other malignant tumors.

Low-grade stromal sarcomas, small cell carcinomas, carcinoid tumors, and melanomas may look similar to GCTs on low power, but these other tumors lack nuclear grooves, are more hyperchromatic, and often contain more mitotic figures than GCTs.

Juvenile-type granulosa cell tumor (JGCTs)

JGCTs have little morphologic similarity to those of the adult type. However, their gross appearance can be similar to AGCTs in that they often are a mixture of solid and cystic components with many areas of hemorrhage.

Microscopically, they have a distinct appearance with round hyperchromatic nuclei, most often lacking the nuclear grooves found in the adult type.

Nuclear atypia often is more severe with more mitotic figures than are found in the adult type, consistent with their more aggressive phenotype. The cytoplasm often is more abundant and dense in JGCTs.

Thecomas

Thecomas usually are tan or yellow with an average size of 7-8 cm. These tumors are bilateral in fewer than 3% of cases.

Microscopically, they are composed of round or ovoid cells with pale nuclei and a lipid-rich cytoplasm. Mitoses usually are less than 4 per 10 high-power fields. Hyaline bands often are found interspersed between cells.

Luteinized thecomas also contain cells with a lipid-rich cytoplasm but are set within a more fibromatous stroma.

Most of these tumors are hormone-producing tumors and cause postmenopausal bleeding in as many as two thirds of patients. Luteinized thecomas also may be androgenic and, if so, tend to occur in younger women.

Types

- adult-type granulosa-cell tumor (AGCT)
- juvenile-type granulosa cell tumor (JGCT)
- fibroma-thecoma tumor groups

Synopsis

- most commonly oberved tumors in post-menopausal women
- usually unilateral.
- solid tumor with a white-yellow cut surface

- Microscopically

  • association of granulosa cells (granulosa cell tumor), theca cells (thecoma) or various proportions of both cells.
  • tumor cells may be luteinized.
  • The granulosa cells are cuboidal to polygonal cells that are arranged in cords, sheets or strands.
  • The theca cells are spindle cells and are arranged in sheets.

See also

- testicular tumors
- ovarian tumors