Echogenic rind on breast ultrasound holds diagnostic significance

The presence of an echogenic rind surrounding suspicious breast masses on ultrasound may serve as a more specific sign of malignancy, according to research published September 17 in the American Journal of Roentgenology.

Echogenic rinds are thick hyperechoic bands that surround a mass, often disrupting the texture of surrounding tissue. They can be found most often in invasive ductal and lobular carcinomas, wrote a team led by Derek Nguyen, MD, from Duke University in Durham, NC. The group noted that including the rind in size measurements reduces tumor underestimation compared to surgical pathology.

“These results provide insights into the clinical implications of an echogenic rind on ultrasound,” the Nguyen team wrote.

The BI-RADS 6th edition is expected to include language related to breast ultrasound, which the team highlighted will include an echogenic rind as a new associated feature.

Nguyen and colleagues evaluated whether including this feature improves breast malignancy diagnosis. They also studied associations between the pathologic tumor characteristics of an echogenic rind and a suspicious mass on breast ultrasound.

Using a retrospective data set, the researchers included 511 women with an average age of 52 in their study. The women had 583 suspicious masses in total (BI-RADS 4 or 5), 249 of which were diagnosed as breast malignancy.

Diagnostic transverse ultrasound image of the left breast in a 64-year-old woman shows irregular hypoechoic nonparallel mass with indistinct margins corresponding to palpable finding, assessed as BI-RADS category 4. Both readers assessed mass as having associated echogenic rind with complete circumferential extent (arrowheads). Ultrasound-guided biopsy of mass yielded diagnosis of invasive ductal carcinoma (intermediate grade, luminal A molecular subtype, no lymphovascular invasion).ARRS

Two radiologists independently reviewed ultrasound examinations for echogenic rinds (requiring ≥25% circumferential extent) associated with masses. They also measured masses with and without the inclusion of echogenic rinds.

The presence of an echogenic rind yielded high specificity values, including 81% and 85% for readers one and two, respectively. However, it also led to modest sensitivity, 58% for reader one and 51% for reader two.

The presence of an echogenic rind also showed significant associations with invasive cancer and invasive cancer molecular subtype for both readers. This feature is more often found in invasive ductal and lobular breast cancers and in HER2-enriched and luminal A subtypes.

In 168 resected malignancies, the team assessed the difference between pathologic tumor size (average, 19 mm) and ultrasound-based mass size, without and with inclusion of echogenic rinds. For reader one, the differences were 4 mm and 3 mm, while reader two indicated differences of 7 mm and 5 mm, respectively.

The study authors highlighted that despite the results, accuracy for a diagnosis of breast malignancy “was not improved by requiring a greater circumferential extent to define the presence of an echogenic rind.”

“Interreader agreement was moderate for the presence of an echogenic rind and minimal for classification of an echogenic rind’s circumferential extent,” they added.

Still, the team recommended that radiologists should consider including any identified echogenic rind in their routine ultrasound measurements for suspicious masses.

“By more reliably delineating tumor margins and disease extent, such measurements could aid surgical planning, particularly for breast-conserving surgeries,” the group wrote.

Read the full study here.