Breast hamartoma: reassessment of an under-recognised breast lesion.

AIMS: Breast hamartomas are an under-recognised lesion because they lack a distinctive microscopic appearance. Microscopic diagnosis can often conclude 'no significant lesion' or 'normal breast tissue', leading to repeated biopsies and diagnostic delay. We describe the histological, immunohistochemical and radiological features of breast hamartomas with the aim of identifying specific signs to facilitate their diagnosis and to differentiate them from normal breast and fibroepithelial lesions. METHODS AND RESULTS: Forty-seven breast hamartomas were reassessed (histological diagnosis and imaging features). An immunohistochemical study [oestrogen receptor (ER), progesterone receptor (PR), CD34, high-mobility group A2 (HMGA2)] was performed. On breast imaging, hamartomas most often presented as probably benign solid masses with circumscribed margins and variable densities. Histologically, breast hamartomas resembled normal breast, although their stromal component was predominant, separating randomly scattered epithelial elements with areas of pure collagenous stroma. Pseudoangiomatous stromal hyperplasia (PASH) was present in 93.6% of cases and CD34 antibody highlighted intralobular, perilobular and interlobular distribution of CD34-positive fibroblasts. By comparison, CD34 was mainly expressed in the intralobular normal breast tissue stroma. Hamartoma stromal cells expressed HMGA2, ER and PR in 79%, 66% and 76.3% of our cases, respectively, compared to 7.7%, 23% and 19% in normal breast tissue, respectively (P < 0.0001; P = 0.0005; P < 0.0001). CONCLUSIONS: After ascertaining that core needle biopsy is effectively intralesional, breast hamartomas can be diagnosed with confidence by taking into account the presence of stromal changes, PASH, interlobular distribution of CD34-positive fibroblasts, HMGA2 and hormonal receptor stromal expression.

Management of radial scars/complex sclerosing lesions of the breast diagnosed on vacuum-assisted large-core biopsy: is surgery always necessary?

AIMS: The diagnosis of radial scars/complex sclerosing lesions (RSs/CSLs) onpercutaneous biopsy carries a risk of histological underestimation. Consequently, surgical excision is often performed in order to exclude a possible associated malignancy. The aim of this study was to assess the rate of 'upgrade to carcinoma' upon subsequent surgical excision of RS/CSL cases diagnosed on vacuum-assisted large-core biopsy (VALCB). We also analysed the risk factors for upgrade in order to determine a subset of patients who could avoid surgery and benefit from conservative management with clinical and imaging follow-up. METHODS AND RESULTS: This was a retrospective observational single-centre study on 174 consecutive RS/CSL cases diagnosed on VALCB from May 2008 to October 2015. Univariate analysis was performed to identify clinical, radiological and histological risk factors for upgrade. Surgical excision was performed following VALCB diagnosis of 88 RS/CSL cases with or without associated atypia. The overall rate of surgical upgrade to carcinoma was 9.1% (8/88). None of the benign biopsies without atypia was surgically upgraded. Additional to atypia, risk factors for upgrade were non-incidental finding of the RS/CSL, the mammographic appearance, and the number of fragments obtained during the biopsy procedure (P < 0.05). CONCLUSION: We demonstrate that VALCB revealing an RS/CSL is reliable for excluding malignancy when there is no associated atypia and when radiological and histological findings are concordant. In such cases, surgery can be avoided in favour of clinical and imaging follow-up. When an RS/CSL is associated with atypia, the decision to perform surgical excision depends on other associated risk factors.