i) Granulosa-Stromal Tumours

Types

Granulosa cell tumours include an adult (95%) and juvenile (5%) type. They contain at least 10% granulosa cells. They may contain theca or fibrous cells.
Thecomas contain theca cells and a fibrous component.
Fibroma and fibrosarcoma resemble their soft tissue counterparts.

Epidemiology

Granulosa cell tumours are the most common type (about 2% of all ovarian tumours). Thecomas are rare (0.5% of sex cord-stromal tumours). Fibromas are the most common sex cord-stromal tumour, making up 4% of diagnoses. Common to these tumours is their age range, where they mostly occur in post-menopausal women. Less than 10% of cases occur in under 30 year olds.

Aetiology

Aetiology is unknown in most cases. A minority of cases occur in the nevoid basal cell carcinoma syndrome (Gorlin syndrome); about 75% of female patients develop multifocal and bilateral fibromas of the ovary.

Clinical features

Granulosa cells and thecomas may produce oestrogen and cause post-menopausal bleeding; in pre-menopausal women they may cause amenorrhoea; in pre-pubertal girls they can cause precocious puberty. A number will present with an abdominal mass, particularly those that are not hormone secreting. Fibromas often present with an abdominal mass, incidentally, or with ascites. A rare clinical syndrome is Meig's syndrome, which consists of ascites and pleural effusion in association with a fibroma of the ovary; these resolve when the lesion is removed.

Pathological features

Granulosa cell tumours

Granulosa cell tumours are often large at presentation. They are yellow to tan. The microscopic features include a population of granulosa cells, which are small round blue cells with a nuclear groove. There are several architectural patterns, including a microfollicular pattern which contains Call-Exner bodies, which appear similar to rosettes. The granulosa cells lie within a thecofibromatous stroma (see below). The juvenile variant contains cells with prominent cytoplasm and no nuclear grooves.

Thecoma

Thecomas are stromal tumours that contain a mixture of theca cells and fibromatous tissue. They are bright yellow macroscopically. Microscopically, the theca cells are usually large, with a vacuolated lipid rich cytoplasm and small nucleus.

Fibroma

Fibromas are tumours that lack granulosa and theca cells, instead consisting purely of spindle cells often arranged in a storiform pattern. They are white and firm on macroscopic appearance.

Fibrosarcoma

This is the most common sarcoma of the ovary, which is fortunately rare.


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