Flame-shaped breast | Radiology Signs

Answer:

The flame-shaped or dendritic pattern is a spiculated, branching subareolar density with linear, finger-like projections radiating from the nipple into the surrounding fat, typically toward the upper-outer quadrant. It is the appearance of the chronic, fibrotic phase of gynecomastia, usually once the process has been present for more than a year, and it is the pattern most easily mistaken for carcinoma because of its spiculated margins. It is one of three recognised patterns. The nodular pattern is a fan- or funnel-shaped subareolar density, centred on the nipple, whose margins blend imperceptibly into the surrounding fat rather than forming a discrete mass; it is the appearance of florid gynecomastia, typically within the first year of onset. The diffuse glandular pattern resembles a heterogeneously dense female breast and is associated with exogenous oestrogen. The features that distinguish gynecomastia from male breast carcinoma are position and margin: gynecomastia is symmetric about the nipple, has no true mass and no distortion, whereas carcinoma is typically eccentric to the nipple, forms a discrete mass with irregular or spiculated margins, and may show microcalcifications, skin or nipple retraction and axillary adenopathy. Ultrasound is used to problem-solve, showing a subareolar hypoechoic star-shaped lesion with finger-like projections (“spider legs”) in the dendritic pattern, or a fan- or disc-shaped hypoechoic nodule in the nodular pattern, without a discrete mass. The underlying cause should be sought clinically, since gynecomastia reflects an altered oestrogen to androgen ratio from puberty, senescence, hepatic or renal failure, hypogonadism, testicular or adrenal tumours and a long list of drugs including spironolactone, digoxin, cimetidine and antiretrovirals.

Why is it called so?

The finger-like projections of dense fibrous tissue radiate from the nipple into the fat like the tongues of a flame.

Pathophysiology

Gynecomastia is proliferation of the ductal and stromal components of the male breast driven by an increase in the ratio of oestrogen to androgen activity. In the early florid phase there is ductal epithelial hyperplasia with a loose, oedematous, highly vascular periductal stroma, which is why the tissue is soft and tender and blends into the surrounding fat, giving the fan-shaped nodular density. If the stimulus persists beyond about a year the stroma becomes densely fibrotic and hyalinised and the ducts branch and radiate within it, producing the spiculated, flame-shaped dendritic pattern with its finger-like projections. Because ductal proliferation is centred on the nipple where the ducts converge, the process is always subareolar and symmetric about the nipple, which is the anatomical basis for the key distinction from carcinoma.

Alternative names: Dendritic gynecomastia pattern; spider-leg or finger-like subareolar density

Other associated named signs: Nodular pattern and diffuse glandular pattern of gynecomastia

References

1. Lattin GE Jr, Jesinger RA, Mattu R, Glassman LM. From the radiologic pathology archives: diseases of the male breast: radiologic-pathologic correlation. Radiographics. 2013;33(2):461-89. PMID: 23479708.