Introduction
•While the standard of care for management of atypical papilloma at core-needle biopsy (CNB) is surgical excision due to numerous studies showing high rates of upgrade to carcinoma, surgical management after CNB diagnosis of intraductal papilloma (IDP) remains controversial
•Some studies have recommended excision of all IDPs due to reported high rates of upgrade, and inability of imaging studies to accurately classify the lesion; however, most of these series did not take into account radiologic-pathologic concordance, which may have lead to falsely high upgrade rates
•A number of radiologic an histologic features predictive of upgrade rate have been suggested: Size >/= 1.5mm on imaging, the presence of microcalcifications, and older patient age
Findings
•The study population consistent of 189 women with CNB diagnosis of IDP, and a total number of 196 IDPs. 166 women underwent excision and 24 were followed clinically and radiologically without excision
•A residual IDP was present in 107 excision specimens (62.6%)
– 39 cases (22.8%) harbored a high-risk lesion (19 cases of atypical ductal hyperplasia, 7 cases of atypical lobular hyperplasia, 4 cases of lobular carcinoma in situ, 1 columnar cell change with atypia, and 8 radial scars) that was not present in the initial CNB sample.
•The upgrade rate to carcinoma (2 invasive lobular carcinomas and 2 cases of DCIS) in the EXC specimen was 2.3% (4 of 171 cases).
– DCIS involved the residual IDP in 1 case (true upgrade). The other 3 carcinomas were at least 0.8mm from the residual IDP (incidental upgrades
•Age was not significantly related to an upgrade, but all patients with carcinoma were >/= 50 years old. All patients with upgrade were asymptomatic
•There were no statistically significant differences in the radiologic characteristics of the lesions with and without upgrade
•IDP fragmentation was the only histologic parameter associated with an upgrade. All 4 IDPs with an upgrade and 77 of 167 IDPs (46.1%) without an upgrade were fragmented (P=048). Other parameters including histologic size of the IDP, presence of microcalcifications, and complete removal were not predictive of an upgrade
Conclusions
•In this study, the authors evaluated a large cohort of patients with IDPs diagnosed with radiologic-pathologic concordant CNB. They found a 2.3% upgrade rate (4 of 171 CNBs), confirming that the upgrade rate is low in IDPs with a radiologically-pathologically concordant CNB
•Their data suggests that close radiologic follow-up constitutes appropriate management for these patients
http://www.ncbi.nlm.nih.gov/pubmed/27315013
Introduction
•Adenomyoepithelial proliferations comprise a spectrum of hyperplastic and neoplastic lesions characterized by dual differentiation into ductal (luminal) and myoepithelial cells
•The lobulated variant of adenomyoepithelioma (AME) of the breast is histologically identical to epithelial-myoepithelial carcinoma of the salivary gland (Seifert, 1998)
– Its usually benign clinical behavior is related to the smaller average size in the breast versus in the salivary gland, and the relative ease of resecting the breast tumors with negative margins
Clinical features
•AME present usually as a solitary mass lesion or discovered on imaging studies
•Most are located centrally in the breast
•They are more frequent in postmenopausal women, although they occur in all ages; rarely they are seen in men
Macroscopic features
•Most are solid, well circumscribed, with bossellated or multi-lobulated outline, and most lack a capsule; focal cystic change may occur
Histopathological features
•Most AME have a multilobulated architecture without evidence of a capsule
•Sclerosis of the central area of the tumor is common, and necrosis of the central zone can occur
•Based on architecture, AME can be classified into lobulated, papillary, tubular, and mixed patterns
•Classical low-grade or benign AME has a relatively uniform admixture of small ducts and surrounding myoepithelial cells
Immunohistochemical features
•The IHC features of AME highlight is dual epithelial and myoepithelial composition
– Myoepithelial cells can be highlighted by p63, actins (SMA, MSA), calponin, smooth muscle heavy chain myosin, and CK5/6
– The luminal ductal epithelial cells stain for low molecular weight keratins Cam5.2, CK7, CK8/18, and EMA
•Immunostains for ER and PR are either negative or weakly positive in a patchy pattern (vs low-grade ductal carcinoma
Differential diagnosis
•The differential includes papilloma with myoepithelial hyperplasia, fibroadenoma, phyllodes tumor or tubular adenoma with AME-like areas, invasive ductal carcinoma, ductal adenoma, and adenosis nodules
•Table 2 shows helpful features in distinguishing these
Malignant AME
•AME are usually slow glowing, with very low metastatic potential, but they have potential for malignant progression
•Malignant AME occurs more frequently in >60 year olds, and is a large tumor; it is often preceded by history of longstanding stable mass followed by a period of rapid growth
•Grossly, they are still partially well circumscribed, but microscopically are infiltrative; often, cystic degeneration and necrosis is seen
•The malignant components can be either ductal, myoepithelial, or both (Table 3)
Clinical behavior
•Most simple AMEs are cured by complete excision
•Local recurrence may occur, possibly related to multinodular growth or satellite nodules
•Malignant AME has greater potential to recur locally and has significant metastatic potential; histologic grade of the malignant component likely reflects the clinical behavior
Take-home messages
•AME of the breast is an uncommon benign tumor that may be mistaken for a carcinoma in core biopsies
•AME of the breast may undergo malignant transformation
•Malignancy arising within AME may be biphasic or may show either ductal or myoepithelial differentiation
•The metastatic potential of malignant AME appears to be related to the grade of the malignant component of the lesion