Consensus document on preoperative diagnostic procedures in breast lesions

Abstract

Currently, percutaneous sampling via core needle or vacuum-assisted biopsy is the primary choice to guide the management of patients with clinical or screen-detected breast lesions. Preoperative biopsies allow physicians to get pathological diagnoses as well as key prognostic and predictive data about the nature of the investigated process. Namely, adequate biopsy sampling is crucial for assigning lesions to one diagnostic category (B1-B5). Similarly, evaluating morphological (histotype, vascular invasion, necrosis, etc.) and immunohistochemical/molecular features (ER, PR, Ki-67, and HER2) is the key to address the most effective therapies, especially in the neoadjuvant setting. The multidisciplinary team should always discuss the results of percutaneous biopsies, whose global integration with clinical and radiological findings will drive the adoption of specific treatment options, particularly for uncertain (B3) and suspicious/malignant (B4-B5) lesions.

In the present work, we report a comprehensive overview of breast percutaneous biopsy techniques, diagnostic categories, and multidisciplinary management based on widely acknowledged evidence of good clinical practice.

Keywords: breast cancer; consensus; multidisciplinary management; preoperative biopsy.

Figure 1.

Biopting sampling fragments, providing material poorly representative for biomarkers evaluation (A) Low-power microphotograph of another core-needle biopsy, collecting four highly cellular representative cores, suitable for biomarker evaluation (B). Higher magnification reveals a micropapillary invasive breast carcinoma (C).

Figure 2.

Mammogram showing an architectural distortion, seen as focal spiculated retraction on detailed viewing, classified by the radiologist as BI-RADS 4B (A). Histological examination of the VAB sampled area (B) revealed foci of desmoplastic stroma (C) embedding angulated glandular structures staining negative for the myoepithelial marker calponin (D), consistent with tubular carcinoma. The preoperative diagnosis was then confirmed at surgical resection: in this latter, a fibrosclerotic area with finger-like margins recalling mammographic findings was observed (B, E), enclosing malignant well-differentiated glands with intraluminal apical snouts (arrow) (F).

Figure 3.

VAB examples of FEA (A, B) showing ductal structures lined by multiple layers of monomorphic roundish cells with apical snouts and monomorphic low-grade atypia. Low (C) and medium-power (D) pictures from another case, revealing, close to FEA foci, a glandular proliferation with architectural growth pattern (solid, cribriform, and micropapillary) and atypia equal to low-grade DCIS. Such a lesion was technically diagnosed as AIDEP/ADH on CNB due to its size (< 2 mm) as sampling limitations prevented precise assessment of its extent.

Figure 4.

Mammogram showing an asymmetric area of increased density with sparse microcalcifications (arrow, classified by radiologist as BI-RADS 4B) (A). Microcalcifications were confirmed by radiography of the VAB cores (arrow).(B). At microscopic examination, adjacent to an intraluminal dystrophic calcification (inset) (C), an incidental acinar proliferation (arrow) consistent with classic LN/classic lobular carcinoma in situ was identified (D). The inset underscores E-cadherin negativity of the classic LN cells.

Figure 5.

Biopsy sample of a papillary proliferation displaying fibrovascular structures enriched in stroma (A) lined by epithelial cells with no evidence of atypia (inset). The definitive diagnosis of benign papillary lesion was established on the surgical specimen, supported by the distribution of basal markers IHC staining (not shown) (B). Another biopsy sample showing ductal spaces filled with an epithelial-rich proliferation (C) made up of atypical cells covering thin fibrovascular cores (D). The morphological findings were consistent with a papillary DCIS, further supported by p63 and cytokeratin 14 staining (not shown).

Figure 6.

Mammogram showing sparse microcalcifications and a clusterof coarse heterogeneous calcifications (arrow), classified by the radiologist as BI RADS 4B (A), with the cluster excised by VAB procedure (B). Focal-shaped accumulations of mucin with abundant calcifications (C) in absence of epithelial cells (D), characteristic of a mucocele-like lesion, were noticed at the histological exam of bioptic material. Low (E) and high-power (F) microphotographs from another bioptic case displaying a malignant invasive mucinous carcinoma, characterized by aggregates of carcinomatous cells floating within mucin, associated with scattered peri- and intratumoral psammoma-like calcifications.

Figure 7.

Biopsy fragments of a vascular lesion lined by flat cells without cytological atypia (A), which was later diagnosed as capillary hemangioma on surgical resection (B, C). Although such morphological findings were suggestive of a benign disease, it was prudentially placed into the B3 category due to the difficulty of assessment of cytologycal atypia in vascular channels and of the relationship with the adjacent adipose tissue. Histological features (inset) of another vascular lesion: despite otherwise bland cytological atypia, the suspicion of its malignant nature was raised by the direct infiltration of the surrounding adipose tissue (D). Histological images from the corresponding surgical specimen (E, F), showing, adjacent to well-differentiated areas, highly cellular foci made up of spindle cells with severe cytological atypia (F). Such morphological findings were consistent with the definitive diagnosis of angiosarcoma.

Figure 8.

Densely cellular cores (inset) made up of atypical epithelioid cells associated with melanin pigment, consistent with metastatic malignant melanoma. The neoplastic cells stained positive for Melan-A and HMB45 (not shown).

Figure 9.

Biomarker discordance between primary breast tumor and axillary lymph nodal metastasis: H&E sections displaying an invasive lobular carcinoma with histiocytoid features in the primary tumor (A), compared to no-special type morphology in the nodal localization (B). Immunohistochemically, the neoplastic cells from the primary tumor revealed faint and incomplete membranous HER2 staining (score 1 +) (C), opposite to strong and complete expression (score 3 +) within the nodal metastasis (D).

Figure 10.

Mammogram showing a single cluster of coarse heterogeneous microcalcifications (arrow, BI-RADS 4B) (A) undergoing VAB. Low (B) and high-power magnification (C, D) histological pictures depicting dilatated ductal structures filled with eosinophilic secretion and microcalcifications lined by a single layer of foamy epithelial cells without cytological atypia and a hobnail appearance. Such morphological features were consistent with pseudolactational cystic changes.