Giant lactating adenoma

Abstract

Lactating adenoma is a rare benign breast lesion that most often presents as a small (up to 3 cm), solid, well-circumscribed, solitary, painless, mobile, lobulated mass. The highest incidence occurs in primiparous women (20 to 40 years old) during the third trimester of pregnancy. However, in the rare case presented herein, in addition to its giant size (more than 10 centimeters on palpation), this lactating adenoma is distinctive due to the presence of multiple nodules, poorly defined ultrasonographic margins, worrisome radiologic features, growth since early pregnancy, presence of infarction and association with chronic mastitis. From the clinical-radiologic perspective, the differential diagnoses included abscess associated with puerperal mastitis, phyllodes tumor, and galactocele. Biopsy was performed, and pathologic examination revealed the classic characteristics of lactating adenoma with multiple infarcted areas, leading to an unexpected confirmed case of giant lactating adenoma.

Keywords: Breast; Breast neoplasms; Lactation Disorders.

Figure 1. Gross view of the surgical specimens. A – External surface; The larger mass measured 11 x 10 x 6 cm, while the smaller mass measured 3.0 x 4.5 x 2.0 cm. Both were well-defined brown and lobulated nodules with pseudo-capsule. B – Cut section of the larger mass; Heterogeneous solid mass with small peripheral cysts and central, white chalk-like necrotic area (scale bar = 11 cm).

Figure 2. Photomicrograph of the surgical specimen. A – Lactating adenoma; proliferation of intralobular tubules and acini, closely packed and intermixed with delicate fibrous stroma. Some acini with lumina containing eosinophilic secretions (H&E, 40x); B – Microscopic appearance of grossly chalk-like area demonstrating coagulative necrosis and a hyperbasophilic rim of dystrophic calcification (H&E, 40x).