Fibroadenoma: Clinical sciences

A fibroadenoma is one of the most common benign tumors of the breast and occurs frequently in patients between the ages of 15 and 35 years. Fibroadenomas arise from stromal and epithelial connective tissue cells, which contain receptors for both estrogen and progesterone, which makes these tumors sensitive to hormonal changes. Although the exact etiology of fibroadenomas is unknown, reproductive hormones play a role in their development as they appear during the reproductive years, enlarge during pregnancy, and eventually regress after menopause. Fibroadenomas can be classified as simple, complex, or giant.

Alright, when a patient presents with signs and symptoms of a fibroadenoma, the first step is to obtain a focused history and physical examination. Patients typically present with a breast lump that’s usually painless. In addition, your patient may report changes in size throughout their menstrual cycle, as well as increase in size during pregnancy, or a decrease in size after menopause. On physical examination, you can expect to find a solitary, palpable, unilateral breast mass. The lesion is usually solid, firm, and rubbery in nature with regular borders. In addition, the mass is mobile and non-tender. Although the lesion can be located anywhere in the breast, it is most commonly found in the upper outer quadrant.

Based on your history and physical exam findings, you should suspect a fibroadenoma. Next, order some imaging to get a better idea of what’s going on. If your patient is younger than 35 years, you can order a breast ultrasound; but, if your patient is 35 years of age or older, you should obtain both a breast ultrasound and a mammogram.

Here’s a clinical pearl! Breast findings on imaging can be categorized with a standardized system called BI-RADS, which stands for Breast Imaging-Reporting and Data System. The imaging findings are assigned into categories labeled as 0 to 6. First, 0 means incomplete, which needs additional imaging or comparison with previous images if available. Next, 1 is negative, meaning that mammography is normal, with no findings like masses or calcification; while 2 indicates findings are completely benign, meaning that mammography reveals findings with no probability of malignancy; a category of 0, 1, and 2 can only be used when undergoing routine screening.

On the other hand, 3 is probably benign, meaning that mammography may reveal a finding with minimal malignant potential of less than 2%, so these patients should get follow-up imaging. Next, 4 is suspicious for malignancy, meaning that mammography may reveal a finding with malignant potential between 2 to 94%, where biopsy will likely be indicated. Then, a category of 5 is highly suspicious of malignancy, with malignant potential over 95%. Lastly, 6 is known malignancy that has been proven with biopsy, and requires definitive management with surgery, chemotherapy, or radiation.

Alright, let’s go back to ultrasound and mammogram. Now, if imaging results are normal and there are no findings that would indicate a breast fibroadenoma, then you consider an alternative diagnosis. Of note, this would be considered BI-RADS category 1.

However, in cases where a fibroadenoma is present, ultrasound and mammogram can be used to help classify fibroadenomas, and certain features may indicate if the fibroadenoma is simple, complex, or giant. On the ultrasound, you could see an oval or round lesion, which is generally well-circumscribed and has uniform hypoechogenicity. Similarly, a mammogram can show a well-circumscribed oval mass that is either hypodense or isodense to the surrounding breast glandular tissue. The lesion can appear macrolobulated or with partially obscured margins. If you see these findings on imaging, you can suspect a simple fibroadenoma.

Asymptomatic patients can be considered BI-RADS category 3, so you can follow up with a repeat ultrasound in 6 months to assess stability. If there are no changes on the follow-up ultrasound, your patient can return to routine annual screenings, which include clinical breast exams and serial ultrasounds every 6 months for the first year, and then again at the second year mark.

However, if your patient is symptomatic, reports pain and discomfort, or if the fibroadenoma is enlarging, an ultrasound-guided core needle biopsy can be done to see if it is some other type of malignant lesion. If the biopsy reveals a well-circumscribed, non-encapsulated lesion with both stromal and glandular elements, your diagnosis of a simple fibroadenoma is confirmed.

Now, since fibroadenomas are benign and don’t increase the risk of developing breast cancer, most cases can be managed with observation and reassurance; while indications for surgical removal include atypia, unusual pathologic features, symptomatic cases, or cosmetic concerns.