Submitted by Catherine Evans, MD and Thomas Learch, MD.
A 43-year-old female presents to clinic with reported history of an abdominal mass which has been growing for three years. She reports associated abdominal pressure and increased urinary frequency and denies any abdominal pain. She has history of one prior pregnancy and regular menses.
On physical exam, a large soft, mobile abdominal mass is palpated. Speculum exam shows the cervix very anterior in position located in the suprapubic area. Exam is otherwise unremarkable.
Labs are normal including negative tumor markers (CA-125, HE4, OVA1).
Multiplanar, multisequence MRI images of the abdomen and pelvis demonstrate a massive, part solid/part cystic mass within the abdomen and pelvis displacing surrounding structures. Mass demonstrates heterogenous signal intensity with areas of patchy enhancement. A myometrial claw sign is seen arising from the fundus of the uterus. The left ovary is normal in appearance with multiple small follicles. The right ovary is not discretely identified.
Differential diagnosis includes uterine mass such as pedunculated leiomyoma or leiomyosarcoma. Ovarian etiology is less likely given the “claw sign” described, however cannot be entirely excluded given that the right ovary is not definitely visualized.
The patient underwent hysterectomy with pathology demonstrating leiomyoma with hydropic degeneration, ischemia and infarction.
The “claw sign” or beak sign in radiology refers to normal parenchyma seen extending around a mass and can be a useful clue in determining whether a mass arises from a solid structure or adjacent to it. A myometrial claw sign can be helpful in determining ovarian versus adnexal origin of a pelvic mass.
Uterine leiomyomas are benign tumors of uterine smooth muscle cells and may be intramural, subserosal or submucosal in location. Subserosal fibroids can be pedunculated and can simulate an adnexal mass. Fibroids can undergo degeneration, hemorrhage, fibrosis and calcification, leading to heterogenous appearance and variable enhancement on imaging.
Leiomyosarcomas are very rare and may demonstrate irregular shape and indistinct margins on imaging, however these features are nonspecific. They often contain areas of hemorrhage and necrosis. Diagnosis is based on histology.
- Murase E, Siegelman ES, Outwater EK et-al. Uterine leiomyomas: histopathologic features, MR imaging findings, differential diagnosis, and treatment. Radiographics. 19 (5): 1179-97.
- Ueda H, Togashi K, Konishi I et-al. Unusual appearances of uterine leiomyomas: MR imaging findings and their histopathologic backgrounds. Radiographics. 1999;19 Spec No : S131-45.