AIMS: Encapsulated @entity1377 (EPC) is a recognized special type of @entity0 . Despite compelling evidence indicating its invasive nature, although not of a conventional form, the current consensus is to manage EPC as an in-situ disease, based on its indolent clinical behaviour. Although most EPCs are recognized to be of low and intermediate grade, a distinct proportion of these @entity5 do show high cytonuclear grade features. The existence and behaviour of these rare high-grade variants remains to be defined. We aim to characterise these @entity5 and provide evidence to guide their management. METHODS AND RESULTS: In this study, we have identified 12 high-grade EPCs without associated conventional stromal invasion. To further characterize these high-grade @entity5 , a series of invasive @entity1377 (n  =  30) were assessed for the coexistence of EPC. The literature was also reviewed. Approximately 3% of pure EPCs showed high-grade features as defined by nuclear pleomorphism and increased mitotic activity. These @entity5 not only showed histological features associated with @entity146 , but were also often hormone receptor-negative, tended to be of larger size, and were more frequently associated with stromal invasion. Of the 10 @entity1 with follow-up data, one with pure high-grade EPC developed recurrence and died of her disease. CONCLUSION: High-grade EPC is rare, and its histological features and more @entity146 clinical behaviour suggest that consideration should be given to managing it in a similar fashion to conventional forms of invasive @entity0 , based on established clinicopathological parameters.

High-grade encapsulated XXXX : an under-recognized entity.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1377 :: ('MESH:D002291', 'Disease') :: ['papillary carcinomas', 'papillary carcinoma'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast carcinoma'] @entity146 :: ('MESH:D001523', 'Disease') :: ['aggressive', 'aggressive behaviour'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumours']
@entity0 :: (MESH:D001943,Disease) :: ['papillary carcinoma of the breast']
