Table 1

Clinical and ultrasound assessment results"

Table 2

Distribution of ultrasonographic features in different stages of GLM"

Figure 1

Ultrasonographic features of the Non-Mass Stage in GLM (type 1: Track Sign with High Echogenicity on the Inner Wall). (A) shows the appearance of several ducts behind the areola, exhibiting irregular dilation and thickening of the ductal walls; (B) magnified image, reveals the thickened ductal walls with a strip-like or linear high echogenicity on the inner wall. The duct wall is smooth, and lipid-containing secretions (bold arrow) are visible inside the duct. A thin, uniformly hypoechoic halo (thin arrow) surrounds the duct; (C) highlights the blue region, which represents the hypoechoic track sign due to the thickening around the duct."

Figure 2

Ultrasonographic features of the Non-Mass Stage in GLM (type 2: Track Sign with Low Echogenicity on the Inner Wall). (A) shows the appearance of several ducts behind the areola with irregular dilation and thickening of the ductal walls; (B) a magnified image, reveals the thickened ductal walls with roughened inner walls. Dense lipid-containing secretions (bold arrow) are visible within the lumen, and a floating sign is observed upon probe compression. A thick, uneven hypoechoic area (thin arrow) surrounds the duct; (C) highlights the blue region, representing the hypoechoic track sign with uneven thickening around the duct."

Figure 3

Ultrasonographic features of the Non-Mass Stage in GLM (type 3: Track Sign with isoechogenicity on the Inner Wall). (A) shows the ultrasonographic appearance of several ducts behind the areola with irregular dilation and thickening of the ductal walls; (B) a magnified image, reveals significant thickening of the walls of some ducts, with the inner walls becoming thickened and rough, presenting as isoechoic (triangle arrow). No anechoic secretion is observed within the lumen (bold arrow). The surrounding ductal wall is notably thickened, presenting as an uneven hypoechoic area (thin arrow)."

Figure 4

Ultrasonographic features of the Non-Mass Stage in GLM (type 4: Track Sign with Periductal Abscess Formation). (A) shows the ultrasonographic appearance of several ducts behind the areola with irregular dilation. The inner wall of the duct displays linear high echogenicity (triangle arrow), while the surrounding ductal wall is markedly thickened and presents as an extremely hypoechoic area (thin arrow). The stroma around the duct shows decreased echogenicity, slightly higher than that of the surrounding ductal wall (area marked with asterisks); (B) shows the same patient's ipsilateral breast, with a local quadrant demonstrating an irregular mixed echogenic area around the duct, which corresponds to fat necrosis and abscess formation (bold arrow)."

Figure 5

Ultrasonographic features of the Non-Mass Stage in GLM (type 5: coexistence of ductal inflammation, periductal Inflammation, and nodular Structures). (A) shows the sonographic appearance of several ducts behind the areola with irregular dilation. The ductal lumen is further expanded, with the inner walls thickened and rough, presenting as a ring-like high echogenicity pattern, consistent with the donut sign (triangle arrow). Two ducts merge with each other, and the surrounding ductal wall is markedly thickened, presenting as an extremely hypoechoic area (thin arrow). Another duct shows a relatively smaller diameter, with slight thickening of the ductal wall (area marked with an asterisk); (B) shows the same patient's ipsilateral breast, with a local quadrant revealing a nodular structure formed by the coexistence of dilated ducts and periductal fibrosis. Several ductal cross-sections with thickened walls are visible inside, showing high echogenicity, while the surrounding ductal area presents as hypoechoic (area marked with an asterisk)."

Figure 6

Ultrasonographic features of the Mass Stage in GLM. (A-B) show hypoechoic masses (M) with irregular, ill-defined margins. The masses exhibit angular extensions and a false burr sign, characterized by relatively uniform, slender hypoechoic projections radiating from the lesion edges (triangle arrows); (C) demonstrates abundant blood flow within and surrounding the mass, accompanied by skin thickening and edema in the affected area (asterisk); (D) shows thickening of Cooper’s ligaments in some cases (thin arrow)."

Figure 7

Ultrasonographic features of the Abscess Stage in GLM. (A-B) shows a large area of mixed echogenicity in the areolar region. The inner wall of the abscess is irregularly thickened with a rough surface (triangle arrow). Overlying skin edema and thickening are observed (asterisk). (B) shows a dilated duct extending toward the nipple is also visible (thin arrow)."

Figure 8

Ultrasonographic features of the Late Ulceration Stage in GLM. Figure 8 shows a hypoechoic area in the areolar region with relatively smooth and well-defined margins, though some portions appear blurred and irregular (triangle arrow). Surrounding this area, dilated ducts are observed communicating with the lesion and extending toward the nipple. The inner walls of the ducts are smooth, with no observable periductal thickening (thin arrow)."

Figure 9

Ultrasonographic features of the Fistula Stage in GLM. (A) shows a duct-like hypoechoic structure beneath the nipple (N) extending toward the areolar skin. The inner wall of the duct is thickened (thin arrow), and a skin ulceration is visible at the areola (asterisk); (B) demonstrates an irregular sheet-like hypoechoic area extending from the glandular layer through the adipose tissue into the subcutaneous region, with a visible skin ulceration at the surface (asterisk)."

Figure 10

Ultrasonographic features of the Complex Type in GLM (coexistence of multiple stages). (A) shows a hypoechoic nodule located posterior to the nipple (N), with indistinct margins and angular contours. Several dilated ducts are visible surrounding the lesion (bold arrows); (B) demonstrates multiple hypoechoic ducts around the mass with luminal obliteration and thickening of both the ductal walls and surrounding tissues (thin arrows)."