Imaging and Preoperative Diagnosis

Before a diagnosis is confirmed by pathology, your medical team uses specialized imaging and visualization tools to “see” inside the uterus. While these tests are highly advanced, they are preoperative—meaning they provide strong clues but cannot give a 100% certain diagnosis without a tissue sample ^[1].

The FIGO PALM-COEIN Framework

To organize the many causes of abnormal bleeding, doctors use a system called PALM-COEIN ^[2].

• PALM covers structural causes you can see on an image: Polyps, Adenomyosis, Leiomyoma (fibroids), and Malignancy ^[3].
• The “A” category is dedicated to adenomyosis, but there is no specific category just for adenomyoma. Your bleeding cause may be classified under “A” or “L” depending on the radiologic and pathologic interpretation ^[4][3].

Transvaginal Ultrasound (TVUS)

A transvaginal ultrasound is usually the first step. Radiologists now use a standardized language called MUSA (Morphological Uterus Sonographic Assessment) to describe what they see ^[5].

Key features that may be noted include:

• Heterogeneous Myometrium: The muscle of the uterus looks “patchy” or uneven rather than smooth and uniform ^[6].
• Myometrial Cysts: Small, fluid-filled pockets within the uterine muscle ^[5].
• Fan-shaped Shadowing: Linear shadows that look like a handheld fan ^[5].
• Irregular Morphology: Unlike fibroids, which usually have very sharp borders, an adenomyoma may have ill-defined margins ^[1].

Note: These are primarily signs of adenomyosis or nonspecific myometrial change. They are suggestive features, not diagnostic markers that reliably distinguish an adenomyoma from a fibroid ^[1].

The Role of MRI

If an ultrasound is unclear, an MRI provides a high-resolution “map.” MRI is particularly good at looking at the junctional zone (JZ)—the border where the uterine lining meets the muscle ^[7].

• JZ Morphology: An MRI look for an irregular or thickened junctional zone. Doctors look for “fingerlike” projections or an irregular inner border ^[7].
• T2-Hyperintense Foci: These are bright spots on the MRI scan that represent tiny areas of bleeding or fluid (cysts) within the mass ^[8].
• Mapping for Surgery: MRI helps the surgeon see exactly where the mass is located—whether it is intramural (inside the wall) or submucosal (pushing into the cavity)—which dictates how it can be removed ^[9].

When Imaging and Biopsy Disagree: Hysteroscopy

Sometimes, a standard office biopsy (like a Pipelle sampling) comes back “normal” even though an ultrasound clearly shows a mass. This happens because a blind biopsy might only catch the healthy background lining and miss the mass itself ^[9].

In these cases, a hysteroscopy is an excellent tool for direct assessment of the uterine cavity ^[10].

• Direct Vision: A thin camera is inserted through the cervix, allowing the doctor to see the mass directly ^[9].
• Targeted Sampling: Instead of a blind sweep, the doctor can take a sample directly from the suspicious area.
• Identifying APAs: This is crucial for identifying Atypical Polypoid Adenomyoma (APA) ^[9][11].

However, it is important to know that hysteroscopy cannot directly visualize an intramural lesion that is deep in the muscle. A normal hysteroscopy does not rule out a deep lesion, and whole-lesion removal is generally not possible through hysteroscopy when the lesion is deep. Histopathology—not hysteroscopic appearance—is the ultimate diagnostic standard ^[12].