Microglandular adenosis or microglandular adenoma? A molecular genetic analysis of a case associated with atypia and invasive carcinoma

The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, London, UK.
Histopathology (Impact Factor: 3.3). 11/2009; 55(6):732-43. DOI: 10.1111/j.1365-2559.2009.03432.x
Source: PubMed

ABSTRACT Microglandular adenosis (MGA) is a rare breast lesion, which has long been considered to be hyperplastic. However, atypical forms of MGA (AMGA) and invasive carcinomas arising in the background of MGA are recorded. Recent studies have suggested that MGA may be a non-obligate precursor of invasive carcinomas that are negative for hormone receptors and lack HER-2 overexpression (triple-negative phenotype). The aim of this study was to determine whether MGA is clonal and whether it harbours chromosomal aberrations similar to those found in matched invasive ductal carcinoma of no special type (IDC-NST).
We report on a case comprising MGA, AMGA and a high-grade IDC-NST. The three components were separately microdissected and subjected to genetic analysis with high-resolution microarray comparative genomic hybridisation. Identical genetic changes were detected in all components with subsequent acquisition of additional genetic aberrations in the invasive component, suggesting that MGA was the substrate for the development of the invasive carcinoma. Immunohistochemistry revealed concordant profiles across all components, characterized by triple-negative phenotype and variable positivity for basal markers.
Similar to adenomas, MGA is, at least in some cases, a clonal lesion and may be a non-obligate precursor of a subgroup of high-grade triple-negative and basal-like breast carcinomas.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Carcinoma arising in microglandular adenosis (MGACA) is an extremely rare subtype of breast carcinoma. In this study, clinicopathological analysis of MGACA from 11 Chinese patients was conducted. Microscopically, all cases showed a spectrum of structure and glandular proliferations ranging from microglandular adenosis (MGA) to atypical MGA (AMGA) to MGACA. Carcinoma components were composed of high grade ductal carcinoma in situ (DCIS) in 1 case and invasive carcinoma in 10 cases. Invasive carcinomas were grade 3 in 10 tumors and grade 2 in 1. Invasive components in 5 of 10 cases were composed of invasive carcinoma of no special type (NST), and 1 case showed partially acinic cell differentiation. In 5 cases, invasive components were mixed of NST and matrix-producing carcinoma (MPC). All epitheliums in 11 cases were triple negative (ER-, PR-, HER2-), and diffuse positive for CK and S-100 protein. No myoepithelial cells were demonstrable from MGA to invasive components with immunohistochemical staining for P63 and calponin. PAS or reticulin stain showed the presence of a basement membrane around glands in MGA, AMGA, DCIS, and its absence in invasive components. Follow-up time ranged from 10 to 64 months. One patient developed a lung metastasis 24 months after surgery, 10 patients have been alive without recurrence. Our study revealed that MGACA is a distinct subset of breast carcinoma, with triple negative phenotype, high grade nuclear and variable morphology. Despite histopathologic and immunohistochemical features usually associated with a poor prognosis, MGACA seems to have a relatively favorable outcome.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Microglandular adenosis (MGA) of the breast is a very rare and benign proliferative lesion. Most patients complain of a palpable breast mass that may arouse a clinical suspicion of breast cancer. Histopathologically, it is hard to distinguish MGA from breast cancer because of the lack of a myoepithelial layer and infiltrative proliferation. Several studies have reported a strong relationship between MGA and carcinoma arising in MGA, so the mass should be excised completely in cases of MGA determined from a core needle biopsy rather than observation. A 72-years-old woman presented with a palpable breast mass. On physical examination, a mass was palpable in the right upper outer quadrant area and somewhat fixed to the surrounding tissues and pectoralis major muscle. We could not detect any mass or dense lesion on mammography because of a grade 4 dense breast. Ultrasonographic findings revealed a low echoic lesion with indistinct margins. The result of a core needle biopsy was MGA, which was confirmed by excision. We report one case of MGA, which was believed to breast cancer clinically.
    03/2011; 14(1):72-5. DOI:10.4048/jbc.2011.14.1.72
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Breast cancer is a heterogeneous disease encompassing a variety of entities with distinct morphological features and clinical behaviors. Although morphology is often associated with the pattern of molecular aberrations in breast cancers, it is also clear that tumors of the same histological type show remarkably different clinical behavior. This is particularly true for ‘basal-like cancer’, which is an entity defined using gene expression analysis. The purpose of this article was to review the current state of knowledge of basal-like breast cancers, to discuss the relationship between basal-like and triple-negative breast cancers, and to clarify practical implications of these diagnoses for pathologists and oncologists.Keywords: basal-like; breast cancer; definition; practical review; triple-negative
    Modern Pathology 11/2010; 24(2):157-167. DOI:10.1038/modpathol.2010.200 · 6.36 Impact Factor