Papillary lesions of the breast: diagnostic imaging and contribution of percutaneous needle biopsy with 14G needle

PURPOSE: To evaluate the presence of suggestive mammographic, US, color-Doppler, RM findings of 33 PLB and to show the accuracy of the large-core biopsy in evaluating these lesions. MATERIAL AND METHODS: A retrospective review of imaging-guided large-core biopsy of 860 consecutive lesions revealed that PLB were diagnosed in 31/33 cases and 3 were suspicious papillary lesions. Surgical correlation was available for all these lesions. Mammography and US were performed in all patients, Color-Doppler in 13/33 and MR in 10/33. RESULTS: Histological findings by percutaneous biopsy demonstrated 26 (79%) benign, 3 (9%) atypical, and 4 (12%) malignant lesions. Histological findings after surgery confirmed the diagnosis for benign and malignant lesions, while of the 3 atypical lesions, 1 was benign and 2 were malignant. One encysted papillary carcinoma in situ at core-biopsy was classified as invasive papillary carcinoma after surgery. PLB were usually found (52%) in subareolar location and the mean size was 17 mm (range 5-60 mm). The most frequent mammographic appearance of benign PLB was of a well-defined (71%), oval (53%) mass. The microcalcifications had variable features; they were isolated in 3/27 (15%) cases and associated with masses in 4/27 (20%). The mammographic finding of papillary carcinoma was of a well-defined (50%) or ill-defined, oval (50%) or lobulated (50%) mass, but never of a spiculated mass. US finding of the benign PLB most commonly showed a well-defined (84%), oval (84%), complex solid/cystic (52%) mass with frequently (60%) posterior enhancement. US finding of papillary carcinoma was of a well-defined (50%) or ill-defined (50%), oval (50%) or lobulated (50%) mass, most commonly solid-inhomogenous-hypoechoic. Color-Doppler showed high blood flow in 8/10 benign PLB and in 2/3 malignant PLB. Contrast-enhanced MR imaging demonstrated usually well-circumscribed, round masses (71%). The intensity/time curve showed marked focal enhancement (peak signal intensity over 70% at the first minute) in both benign and malignant lesions. DISCUSSION: Often the patients with PBL were symptomatic (for presence of nipple discharge or palpable mass). 31/33 papillary lesions identified at the subsequent imaging-guided large-core biopsy and in the 3/33 remaining lesions percutaneous core-biopsy required a subsequent surgical biopsy for the atypical papillary lesions. US proved to have the highest sensitivity, showing the suggestive feature of a frond-like mass within a dilated duct, and color-Doppler demonstrated high blood flow (which should be considered in differential diagnosis of galactocele). Mammographic finding of papillary lesions was often consistent with benign lesions (fibroadenoma, cyst). MR confirmed the high vascularization of these lesions, showing marked enhancement of the solid component. CONCLUSIONS: US, with Color-Doppler, proved to be the most useful examination for the identification and demonstration of the solid component of these lesions, which, observed further diagnostic investigation. As no definite mammographic, sonographic or RM pattern could be identified to differentiate between benign and malignant PLB, core-biopsy was required. Percutaneous biopsy has shown to be reliable in the diagnosis of benign and malignant PLB (without any false negative): infact, any atypical lesions require surgical examination. The framing of benign and malignant PLB with imaging and core-biopsy was useful because the frequent association of benign PLB with concurrent or subsequent breast carcinoma suggests surgical excision and radiological follow-up.