Struma Ovarii : Microscopic Features

Comments:
Microscopic Features: Struma ovarii is composed of thyroid follicles that range from normal to hyperplastic to adenomatous in appearance. The follicles are lined by cuboidal to flat cells with clear or oxyphilic cytoplasm. The nuclei are uniform, hyperchromatic, and basally located. Mitotic activity is not increased. The follicles are filled with eosinophilic colloid and may contain birefringent calcium oxalate crystals. Parafollicular cells (C cells) are not seen. The follicles are enclosed in scant collagenous stroma in most cases, but stroma can be abundant and edematous. In rare cases, there is stromal luteinization.

The image shows thyroid follicles within the cyst wall in a case of struma ovarii.