The origins of early breast carcinoma

Uniqueness of ductal carcinoma in situ of the breast concurrent with papilloma: implications from a detailed topographical and histopathological study of 50 cases treated by mastectomy and wide local excision

AIMS

To clarify the diagnostic clues of ductal carcinomas in situ (DCIS) associated with papilloma and optimal clinical management of papilloma diagnosed on core needle biopsy (CNB).

METHODS AND RESULTS

A total of 50 surgically resected cases were examined histopathologically and topographically. Thirty-nine cases (78%) spread in segmental fashion. Papilloma and DCIS were intermingled closely in 44 cases (88%), occupying the same areas in varying proportions from DCIS-predominant to papilloma-predominant. The two components occupied discrete areas and collided focally in six cases (12%). Most were non-high-grade. Cribriform and solid architectures with fibrovascular stroma were frequent. The cribriform pattern was unique, consisting of fused tubules separated by fibrovascular stroma. Intraductal myoepithelial cells were present to varying degrees in 40 cases (80%). In 38 cases (76%), points were identified where papilloma and DCIS coexisted or collided within a single lumen (CC point). Forty-eight cases (96%) had either intraductal myoepithelial cells or CC points, implying that DCIS and papilloma existed in the same duct system. Radiology showed segmental abnormalities in 83% of the available cases.

CONCLUSIONS

Intraductal myoepithelial cells do not always guarantee benignity. Surgical resection is recommended for papilloma in CNB when radiology shows segmental abnormalities.

Breast MR imaging: normal anatomy

Dynamic contrast-enhanced magnetic resonance (MR) imaging of the breast is a useful tool for the assessment of both structural and functional anatomy. A basic approach to the interpretation of normal anatomy on breast MR imaging is reviewed in this article.

Malignant transformation and stromal invasion from normal or hyperplastic tissues: true or false?

Carcinogenesis is believed to be a multi-step process, progressing sequentially from normal to hyperplastic, to in situ, and to invasive stages. A number of studies, however, have detected malignancy-associated alterations in normal or hyperplastic tissues. As the molecular profile and clinical features of these tissues have not been defined, the authors invited several well-recognized pathologist, oncologists, biologist, surgeons, and molecular biologist to offer their opinion on: (1) whether these tissues belong to a previously unrevealed malignant entity or focal alterations with no significant consequence? (2) whether these alterations are linked to early onset of cancer or cancer of unknown primary site, and (3) how to further define these lesions?

In situ malignant transformation and progenitor-mediated cell budding: two different pathways for breast ductal and lobular tumor invasion

The human breast lobular and ductal structures and the derived tumors from these structures differ substantial in their morphology, microenvironment, biological presentation, functions, and clinical prognosis. Based on these differences, we have proposed that pre-invasive lobular tumors may progress to invasive lesions through "in situ malignant transformation", in which the entire myoepithelial cell layer within a given lobule or lobular clusters undergoes extensive degeneration and disruptions, which allows the entire epithelial cell population associated with these myoepithelial cell layers directly invade the stroma or vascular structures. In contrast, pre-invasive ductal tumors may invade the stroma or vascular structures through "progenitor-mediated cell budding", in which focal myoepithelial cell degeneration-induced aberrant leukocyte infiltration causes focal disruptions in the tumor capsules, which selectively favor monoclonal proliferation of the overlying tumor stem cells or a biologically more aggressive cell clone. Our current study attempted to provide more direct morphological and immunohistochemical data that are consistent with our hypotheses.

Redefining lumpectomy using a modification of the "sick lobe" hypothesis and ductal anatomy

Objectives. The “Sick Lobe” hypothesis states that breast cancers evolve from entire lobes or portions of lobes of the breast where initiation events have occurred early in development. The implication is that some cancers are isolated events and others are truly multi-focal but limited to single lobar-ductal units. Methods. This is a single surgeon retrospective review of early stage breast cancer lumpectomy patients treated from 1/2000 to 2/2005. Ductal endoscopy was used direct lumpectomy surgical margins by defining ductal anatomy and mapping proliferative changes within the sick lobe for complete excision. Results. Breast conservation surgery for stage 0–2 breast cancer with an attempt to perform endoscopy in association with therapeutic lumpectomy was performed in 554 patients (successful endoscopy in 465 cases). With an average followup of >5 years for the entire group, annual hazard rate for local failure in traditional lumpectomy without ductal mapping was 0.97%/yr. and for lumpectomy with ductal mapping and excision of entire sick lobe was 0.18%/yr. With endoscopy, 42% of patients were found to have extensive disease within their “sick lobe.” Conclusions. Targeting breast cancer lumpectomy using endoscopy and excision of regional associated proliferation seems associated with lower recurrence in this non-randomized series.

Subgross morphology, the sick lobe hypothesis, and the success of breast conservation

Breast carcinoma has a complex subgross morphology in the majority of cases. The malignant transformation usually involves a single breast lobe and may demonstrate peripheral, segmental, or lobar growth patterns in the in situ phase. During the invasive phase, the tumor may grow beyond the borders of the affected lobe. The dimensions of the involved lobe and the pattern of its involvement determine the extent of the disease in the early phase, with the size, type, and position of the invasive foci being additional determinants in more advanced cases. Breast carcinomas of limited extent (occupying a tissue area <40 mm) are proper candidates for breast-conserving surgery. In other cases, careful individual preoperative assessment of disease extent is necessary in making decisions about the most appropriate surgical approach, taking into account the position of the lesion(s) within the breast, the dimensions of the breast, and patient preference.

Molecular phenotypes of unifocal, multifocal, and diffuse invasive breast carcinomas

We analyzed the subgross distribution of the invasive component in 875 consecutive cases of breast carcinomas using large-format histology sections and compared the immunophenotype (estrogen and progesterone receptor expression, HER2 overexpression and expression of basal-like markers, CK5/6, CK14, and epidermal growth factor receptor) in unifocal, multifocal, and diffuse tumors. Histology grade and lymph node status were also analyzed. Unifocal invasive carcinomas comprised 58.6% (513/875), multifocal invasive carcinomas 36.5% (319/875), and diffuse invasive carcinomas 4.9% (43/875) of the cases. The proportion of lymph node-positive cases was significantly higher in multifocal and diffuse carcinomas compared to unifocal cancers, but no other statistically significant differences could be verified between these tumor categories. Histological multifocality and diffuse distribution of the invasive tumor component seem to be negative morphologic prognostic parameters in breast carcinomas, independent of the molecular phenotype.

The role of radiological-pathological correlation in diagnosing early breast cancer: the pathologist's perspective

Early breast carcinoma, defined as purely in situ cancer and invasive carcinomas < 15 mm, represents the most frequent category of breast carcinomas in diagnostic routine in a regularly screened population. These tumors are usually detected with mammography screening and are preoperatively characterized with radiological imaging. The role of pathology in preoperative settings is to help understand the subgross morphology and to confirm malignancy in biopsy material. Postoperatively, the pathologist needs to verify the size of the cancer (defined as the largest dimension of the largest invasive focus), the extent of the disease (defined as the area or the volume of the breast tissue containing all the malignant foci), the distribution of the in situ and invasive lesions (as unifocal, multifocal, or diffuse), and intratumoral and intertumoral heterogeneity (in addition to determining margin status, histologic tumor type, hormone receptor status, and other parameters). Despite their small size, early breast carcinomas often exhibit complex morphology as they are multifocal/diffuse in about 60% and extensive (occupying an area ≥ 4 cm) in 40% of the cases. Routine use of large-format histopathology technique is a prerequisite for detailed correlation of the radiologic and histopathologic findings and for the correct assessment of these parameters. Breast pathologists must be aware of the advantages and disadvantages of the different imaging modalities and have detailed information about the radiological findings before work-up of the operative specimen. Multidisciplinary preoperative and postoperative tumor board meetings are essential in guiding the pathologists and in confirming the radiological findings. Interdisciplinary diagnosis is inevitably becoming the new gold standard in the diagnosis and management of early breast carcinomas.