A 24-year-old woman comes to the office due to a breast lump that she noticed 2 days ago. The patient's menses are regular, occurring every 26 days with 2 days of heavy bleeding and 2 days of light flow. Her last menstrual period was 3 weeks ago. She is sexually active and recently started using combined estrogen/progestin oral contraceptives. The patient is an avid jogger and wears a sports bra almost daily. Family history includes a paternal aunt diagnosed with breast cancer at age 62. Physical examination shows a 4-cm, firm, round, mobile mass in the superior outer quadrant of the right breast.
Which of the following is the most likely diagnosis in this patient?

Question

A 24-year-old woman comes to the office due to a breast lump that she noticed 2 days ago.  The patient's menses are regular, occurring every 26 days with 2 days of heavy bleeding and 2 days of light flow.  Her last menstrual period was 3 weeks ago.  She is sexually active and recently started using combined estrogen/progestin oral contraceptives.  The patient is an avid jogger and wears a sports bra almost daily.  Family history includes a paternal aunt diagnosed with breast cancer at age 62.  Physical examination shows a 4-cm, firm, round, mobile mass in the superior outer quadrant of the right breast. 
Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d893_1f2a_bc81_4b594c0b1a5f_MD0003_00 This young woman with an isolated, firm, mobile palpable breast mass most likely has a fibroadenoma, a benign breast condition common in women age <30 and often sensitive to estrogen. Increased estrogen levels can cause increased fibroadenoma growth, which can make the mass more noticeable to the patient prior to menses or with initiation of combined estrogen/progestin oral contraceptives, as in this patient. Like many benign breast masses, a fibroadenoma typically presents as a small, firm, well circumscribed, and mobile mass. Although fibroadenomas may present anywhere in the breast, they are usually solitary and commonly located in the upper outer quadrant of the breast. In contrast, a breast malignancy (eg, ductal carcinoma) is typically larger, irregularly shaped, and immobile; associated nipple discharge or lymphadenopathy may also be present (Choice A). (Choice B) Fat necrosis of the breast, which occurs due to breast injury (eg, surgery, trauma), typically presents as a unilateral, irregular, firm breast mass with possible ecchymosis of the overlying skin. (Choice D) Fibrocystic breast changes typically cause multiple, small, cyclically tender masses and diffuse nodularity in both breasts. In contrast, this patient has a unilateral, isolated mass. (Choice E) A galactocele is a milk retention cyst of the breast caused by an obstructed duct; it typically occurs in breastfeeding patients and is usually soft and cystic rather than firm. galactocele (Choice F) Mammary duct ectasia can present as a unilateral, isolated breast mass; however, these benign lesions are typically subareolar (not in the upper outer quadrants) and associated with nipple discharge due to inflammation of the subareolar breast ducts. (Choice G) Phyllodes tumors are a rare form of breast tumor that, in the early stages of growth, shares similar characteristics with fibroadenomas (ie, unilateral, isolated, firm, well circumscribed, mobile). However, phyllodes tumors typically grow much larger, resulting in changes to the shape, contour, and skin (eg, necrosis) of the affected breast. Educational objective: An isolated, firm, well circumscribed, and mobile breast mass in women age <30 is commonly a benign fibroadenoma. References: Practice bulletin no. 164: diagnosis and management of benign breast disorders. (http://www.ncbi.nlm.nih.gov/pubmed/27214189)

A 24-Year-Old Woman Comes to the Office Due to a Breast