Clinical presentation and classification
Fibroid symptoms directly depend on the mass effect and node location. Patients may experience menorrhagia (menorrhagia), pain, infertility (infertility), as well as urinary tract compression symptoms. A serious complication is the torsion of a node on a thin stalk, presenting as an "acute abdomen".
Topographically, three main types of nodes are distinguished:
- Submucosal (submucosal) — grow into the uterine cavity, distorting it.
- Intramural (intramural) — located within the muscular layer (myometrium).
- Subserosal (subserosal) — extend outward beyond the serosal membrane.
Imaging principles
Ultrasound examination is the initial and baseline method. On ultrasound, the uterus appears enlarged, with bumpy contours. A typical node is visualized as a hypoechoic solid mass with distinct margins. If calcifications are present in the tissue (as a result of necrosis), they produce posterior acoustic shadowing.
Magnetic resonance imaging (MRI) is used as a second-line method to clarify the diagnosis (especially in differential diagnosis with adenomyosis) and plan minimally invasive interventions (myomectomy, embolization, or MR-guided FUS ablation). On coronal T2-weighted images (T2WI), a typical fibroid demonstrates lower signal intensity compared to normal myometrium.
Computed tomography (CT) is not used for targeted detection of fibroids; nodes are often an incidental finding (via uterine contour distortion and calcifications). Hysterosalpingography (HSG) demonstrates filling defects of the uterine cavity, but is no longer recommended for evaluating submucosal masses.
Types of myoma node degeneration
During growth, nodes may undergo various structural changes, which radically alter their MRI appearance.
| Type of degeneration | MRI: T1WI | MRI: T2WI | Features |
|---|---|---|---|
| Conventional | Intermediate | Low | Enhances less than the myometrium |
| Cystic | Isointense | High | Anechoic zones on ultrasound, do not enhance with contrast |
| Red | High | Variable | Dark hemosiderin rim on T2 |
| Hyaline | Iso/intermediate | Low | Ultrasound appearance like a typical myoma |
| Myxoid | Low | Very high | Layered contrast enhancement |
| Lipoleiomyoma | High | Moderate/high | Signal drop on fat-saturation sequences |
Differential diagnosis challenges
A special diagnostic challenge is posed by cellular fibroids (cellular fibroids). As a rule, these are solitary masses that demonstrate high signal on T2-WI, actively enhance with contrast, and show restricted diffusion.
This pattern makes them extremely similar to early stages of leiomyosarcoma. The key differential diagnostic sign is the absence of hemorrhage foci — they are not characteristic of cellular leiomyoma, but frequently accompany the malignant process.
To memorize degenerations on MRI: "Red — bleeds (bright on T1), Cystic — water (bright on T2), Lipoleiomyoma — fat (darkens on fat-sat)".
Class and exam questions
What is the specific MRI sign of subserursal myoma torsion?
Sagittal scans visualize the "swirl sign" (swirl sign) in the area of the twisted stalk, as well as the appearance of free fluid in the pelvic cavity.
How to distinguish an endometrial polyp from a submucosal myoma node?
It is best to use sonohysterography: fluid introduced into the uterine cavity clearly outlines the polyp. In addition, color Doppler mapping often visualizes a central feeding vessel within the polyp.
What else to study on this topic
- Radiological patterns of endometrial hyperplasia and carcinoma.
- Differential diagnosis of uterine fibroids and adenomyosis.
- Application of sonohysterography in gynecology.
- MR appearance of uterine developmental anomalies (uterus didelphys) and hematometrocolpos.
- Effect of tamoxifen on endometrial structure (formation of polyps and cystic changes).
Master the entire topic in the "Diagnostic Radiology" course
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- Complete study guide on "Uterine Fibroids" and another 2,199 pages on the subject
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Other topics in the section "Diagnostic Radiology of the Abdominal Organs"
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