Mastopathic-type fibroadenoma and ductal adenoma of the breast with false-positive fluorodeoxyglucose positron emission tomography

Abstract

Positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) has been shown to be an effective and accurate diagnostic technique for breast cancer. However, benign breast lesions have also been reported to show a false-positive FDG uptake on PET. We present two cases of benign tumors that revealed FDG uptake on PET and were difficult to distinguish from breast cancer. A 46-year-old premenopausal woman noticed a mass in her right breast. Ultrasonography showed a hypoechoic mass with the size of 7.7 x 3.9 mm and an irregular shape in the right breast. PET demonstrated a focal accumulation of FDG with a maximum standardized uptake value (SUVmax) of 2.1. Excisional biopsy was performed, and ductal adenoma was diagnosed. In the second case, a 36-year-old premenopausal woman was pointed out as showing an abnormality in the left breast on screening mammography. Ultrasonography showed a hypoechoic mass of 1.5 x 1.2 cm in size in the left breast. The lesion was depicted as a mass with prominent enhancement on dynamic CT and a focal accumulation of FDG with SUV max of 3.5 on PET. It was diagnosed as fibroadenoma of mastopathic type histopathologically by excisional biopsy. The readers should be aware that these benign tumors may cause false-positive results on PET.

Myxomatous fibroadenoma of the breast: correlation with clinicopathologic and radiologic features

“…Forty-five Table 1). The percentages of M-FA among the pathologic subtype of FA were 53% (31/59), 14% (5/35), 0% (0/1), and 50% (9/18) for intracanalicular, pericanalicular, organoid, and mastopathic types [5], respectively. The latter type displays epithelial hyperplasia, with solid and cribriform patterns that sometimes mimic intraductal carcinoma.…”

Cytological features of myxomatous fibroadenoma of the breast

“…However, if the epithelial components show marked hyperplastic changes and it is difficult to distinguish between a benign or malignant nature, the presence or absence of metachromasia of the mucus components constitutes a very significant supporting finding. In particular, our previous study indicated that intracanalicular and mastopathic types often show hyperplastic changes of the epithelium and could sometimes be mistaken for carcinomas 6. However, these two subtypes show a high frequency (53% and 50%, respectively) of M‐FAs among FAs 4.…”

“…The latter type displays epithelial hyperplasia, with solid and cribriform patterns that sometimes mimic carcinoma. M‐FA showed a high frequency of the intracanalicular type and mastopathic type 6. It could therefore be mistaken on histological and cytological examination between carcinomas and M‐FA.…”

“…Therefore, fine‐needle aspiration biopsy (FNAC) and/or needle biopsy are needed to be differential diagnosis between them as a next step. The pathological subtype of FA is for intracanalicular, pericanalicular, organoid, and mastopathic types 6. The latter type displays epithelial hyperplasia, with solid and cribriform patterns that sometimes mimic carcinoma.…”

Unexpected focal fluorodeoxyglucose uptake in main organs; pass through or pass by?

“…These should be included in differential diagnosis. The most common benign breast tumor, fibroadenoma, often shows low FDG uptake, but it may have high uptake mimicking a malignant lesion[ 168 , 169 ]. Asymmetrical or nodular appearance of gynecomastia also can mimic malignancy.…”