Uterine lipoleiomyomas result from degeneration of smooth muscle cells in an ordinary leiomyoma and represent a rare benign tumour of the uterus 1.
Lipoleiomyomas have a reported incidence of 0.03-0.20% and are typically found in postmenopausal patients with typical uterine leiomyomas 2.
Although most patients are asymptomatic, they can present with symptoms similar to leiomyomas of the same size and location. Symptoms include, but are not limited to, abdominal/pelvic pain, palpable mass and menstrual abnormalities.
Many considered a uterine lipoleiomyoma as a distinct variety of leiomyoma. Histologically, it is composed of variable amounts of adipocytes and smooth muscle cells, separated by thin fibrous tissue. The exact aetiology is not well known, but is thought to represent fatty metaplasia of the smooth muscle cells of a leiomyoma. Lesions can vary in size from a few mm to a few cm.
Advanced imaging of these lesions allows for differentiation from cystic ovarian neoplasms, which may require surgical therapy 3.
- hyperechoic with a partially hypoechoic rim
- the rim likely represents a layer of myometrium surrounding the fatty central component 3
- posterior acoustic attenuation
- often poor vascularity on colour Doppler examination
- predominantly fat-containing mass arising from uterus
- often contains areas of soft tissue density
Secondary to the predominant fatty component in the lesion, hyperintensity is seen on T1 weighted sequences and chemical shift artifacts are noted. Additionally, fat suppression techniques can be useful in verifying the diagnosis - most of the lesion shows fat suppression 3. Signal characteristics are therefore:
- T1: hyperintensity
- T1 FS: hypointensity (saturates out)
- T2: hyperintensity
- T2 FS or STIR: hypointensity (saturates out)
Treatment and prognosis
Treatment is similar to leiomyomas and is dependent on the clinical symptoms and the size/location of the lesion. Uterine artery embolization or surgical excision can be performed, as indicated 1. In general, they are benign tumours with favourable prognosis.
General imaging differential consderations include:
- benign cystic ovarian teratoma
- malignant degeneration of cystic teratoma
- non-teratomatous lipomatous ovarian tumour
- pelvic lipoma
- pelvic liposarcoma
- very rare lipomatous tumours of the uterus: angiomyolipoma, fibromyolipoma, myelolipoma
Ultrasound - gynaecology
- ultrasound (introduction)
- acute pelvic pain
- chronic pelvic pain
- Mullerian duct anomalies
- ovarian follicle
- ovarian torsion
- pelvic inflammatory disease
- ovarian cysts and masses
- ovarian cyst
- corpus luteum
- haemorrhagic ovarian cyst
- ruptured ovarian cyst
- ovarian epithelial tumours
- granulosa cell tumours of the ovary
- paraovarian cyst
- polycystic ovaries
- ovarian hyperstimulation syndrome
- post-hysterectomy ovary
- fallopian tube
- 1. Prieto A, Crespo C, Pardo A et-al. Uterine lipoleiomyomas: US and CT findings. Abdom Imaging. 25 (6): 655-7. Abdom Imaging (link) - Pubmed citation
- 2. Tsushima Y, Kita T, Yamamoto K. Uterine lipoleiomyoma: MRI, CT and ultrasonographic findings. Br J Radiol. 1997;70 (838): 1068-70. Br J Radiol (abstract) - Pubmed citation
- 3.Avritscher R, Iyer RB, Ro J et-al. Lipoleiomyoma of the uterus. AJR Am J Roentgenol. 2001;177 (4): 856. AJR Am J Roentgenol (full text) - Pubmed citation