Fibroma (Ovarian), Thecoma, and Fibrothecoma

Synonyms/Description

Thecoma, fibroma, and fibrothecoma are all tumors belonging to the thecoma-fibroma group of stromal tumors (per the World Health Organization classification of ovarian sex cord–stromal tumors).

Etiology

Thecoma-fibroma tumors are a closely related group of benign tumors that arise from ovarian stroma and are often difficult for the imager and even pathologist to distinguish. The fibroma contains spindle cells, and is the most common type of sex cord-stromal tumor, accounting for 6% of all ovarian tumors. They are usually asymptomatic although they can be large.

The thecoma arises from theca (stroma) cells and can produce estrogen, much like the granulosa cell tumors, thus sometimes presenting with abnormal uterine bleeding. Many of these tumors are a mixture of cell types and are called fibrothecoma.