Low-grade ductal carcinoma in situ and invasive mammary carcinoma with columnar cell morphology arising in a complex fibroadenoma in continuity with columnar cell change and flat epithelial atypia

Sclerosing Fibroadenoma With Atypical Ductal Hyperplasia Mimicking Invasive Carcinoma: A Case Report With Diagnostic Pitfall

Fibroadenoma (FA) of the breast is a benign fibroepithelial lesion rarely showing atypical epithelial overgrowth. We present the case of a 50-year-old Japanese woman with sclerotic FA with atypical ductal hyperplasia (ADH)/ductal carcinoma in situ (DCIS). A small mass was detected during clinical examination in the upper lateral area of the left breast. Hematoxylin and eosin stain section of a breast needle core biopsy specimen showed trabecular growth of atypical epithelial cells without distinct myoepithelial lining in the sclerotic stroma. Initial pathological diagnosis of the biopsy specimen was invasive carcinoma of no special type. The surgical specimens included a well-bordered nodular lesion with similar histological findings to that of the biopsy specimen, but, the myoepithelial lining was highlighted by cytokeratin 5 (CK5) immunohistochemistry. The tumor cells were diffusely ER-positive and completely negative for CK5 in immunohistochemical staining. Final diagnosis based on the results of immunohistochemical staining and consultation between two breast pathology specialists was the lesion as sclerosing FA with ADH/DCIS. Awareness of the unique histological subtype of FA is important to avoid pathological misdiagnosis and clinical overtreatment.

A deep learning model for breast ductal carcinoma in situ classification in whole slide images

The pathological differential diagnosis between breast ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) is of pivotal importance for determining optimum cancer treatment(s) and clinical outcomes. Since conventional diagnosis by pathologists using microscopes is limited in terms of human resources, it is necessary to develop new techniques that can rapidly and accurately diagnose large numbers of histopathological specimens. Computational pathology tools which can assist pathologists in detecting and classifying DCIS and IDC from whole slide images (WSIs) would be of great benefit for routine pathological diagnosis. In this paper, we trained deep learning models capable of classifying biopsy and surgical histopathological WSIs into DCIS, IDC, and benign. We evaluated the models on two independent test sets (n= 1382, n= 548), achieving ROC areas under the curves (AUCs) up to 0.960 and 0.977 for DCIS and IDC, respectively.

Breast cancer arising within fibroadenoma: collective analysis of case reports in the literature and hints on treatment policy

Background

Breast cancer arising within a fibroadenoma (BcaFad) is rare; the rate varies from 0.002% to 0.125% in fibroadenoma specimens. Owing to its rarity, the clinicopathologic feature and treatment principle of BcaFad is still not clear. Therefore, the aim of this study was to perform a collective analysis of case reports in the literature to identify the characteristics and optimal treatment for BcaFad.

Methods

We analyzed an aggregated sample of 30 patients with BcaFad from case reports in the literature (n =24 cases) and our present study (n =6 cases). We collected and analyzed the clinicopathologic features and prognoses of patients with BcaFad, as well as treatments they received.

Results

The patients’ mean age at diagnosis was 46.9 years. Twenty BcaFad patients (66.7%) received breast-conserving surgery (BCS), and nine other patients (30.0%) were treated with mastectomy. The rate of lymph node metastasis in BcaFad patients was 23.8%. The breakdown of the histological types of BcaFad was invasive ductal carcinoma (53.3%), followed by ductal carcinoma in situ (23.3%), lobular carcinoma in situ (16.7%) and invasive lobular carcinoma (13.3%). More than half of patients with positive hormone receptor status received hormone therapy. Most BcaFad patients with lymph node metastases received chemotherapy, and 20.0% of BcaFad patients treated with BCS received further radiotherapy. Only one patient had recurrence after surgery, and another had lung metastasis when diagnosed with BcaFad.

Conclusions

Most BcaFad patients could be managed by BCS. Adjuvant radiotherapy could be performed, but was not mandatory. Chemotherapy should be considered as a treatment option in the presence of lymph node metastasis.