Struma ovarii should be suspected whenever encountering a complex multiloculated lobulated cystic ovarian mass with multiple cysts of varying signal intensity, sizes and a lacelike pattern of enhancement ^1-4.

The comet tail artefact seen on ultrasound, as well as the variable signal intensity on MRI were consistent with gelatinous intralesional colloid.

Struma ovarii is a rare, usually benign ovarian monodermal teratoma predominantly consisting of thyroid follicular tissue and colloid contents. 5-10% of struma ovarii tumors are reported to be malignant, histopathologically revealing papillary thyroid carcinoma ¹.

Most are discovered incidentally as the majority of lesions are asymptomatic, unless the tumor is very large, resulting in ovarian torsion. Around 5% of struma ovarii patients may present with signs of thyrotoxicosis. Ascites and elevated CA 125 may also be encountered ¹.

Our patient's thyroid function test and tumor markers were normal.