The "Double Ovary" Sign: A Unique Sonographic Observation in Isolated Fallopian Tube Torsion.

Isolated fallopian tube torsion (IFTT) is a rare subset of adnexal torsion. Timely diagnosis of IFTT is essential for preservation of the fallopian tube. However, a pre-operative diagnosis is challenging due to nonspecific symptoms and findings on physical exam. In addition, ultrasound (US) is typically the initial imaging modality in this setting and adnexal torsion may not be considered when normal ovaries are seen. In this small case series, we introduce the "double ovary" sign, a unique observation on US characterized by two adjacent structures: the ovary and the twisted fallopian tube giving rise to an ovary-like, cystic structure. We present three cases in which IFTT was diagnosed preoperatively.