Encapsulated Papillary Carcinoma of the Breast

Abstract

SPC is more frequently associated with coexisting conventional invasive carcinoma than IPC (P<0.05). Although the majority of papillary DCIS and some cases of IPC and SPC (both called encapsulated PC) that are surrounded by an intact layer of myoepithelial cells are considered to be true in situ lesions, PC lacking a peripheral layer of myoepithelial cells can be regarded as a special type of invasive carcinoma associated with low incidence of stromal/skeletal muscle invasion, low frequency of lymph node metastasis (3%), and infrequent development of local or distant recurrence. These lesions are therefore characterized by indolent behavior and extremely favorable prognosis. Encapsulated PC can be treated with adequate local therapy. Routine use of adjuvant therapy, particularly chemotherapy, is clearly not appropriate in view of the very low risk of subsequent events. However, hormonal therapy may be indicated in certain cases such as recurrent PC.

Invasive Lobular Carcinoma Mimicking Papillary Carcinoma: A Report of Three Cases

“…There is still controversy about the nature of papillary carcinoma (PC), but accumulating evidence indicates that PCs lacking myoepithelial cells have the biological potential to behave as an invasive disease with an expansile papillary growth pattern and indolent clinical behaviour. This is supported by the occasional development of lymphovascular invasion, lymph node metastases and recurrences in some cases with typical PC morphology [1,2,3,4,5,6,7]. PC has been reported to be of ductal origin, and, to our knowledge, all reported cases have been described as such.…”

“…There is compelling evidence to support the potential invasive nature of PC [2,4,5,6,10], but the molecular mechanisms underlying this unique growth pattern and the ultimate behaviour of these lesions remains to be defined. The current recommendation is to manage PC as an in situ disease similar to DCIS (carcinoma in situ) [4].…”

“…The current recommendation is to manage PC as an in situ disease similar to DCIS (carcinoma in situ) [4]. Although most authors [5,11] consider EPC synonymous with intracystic (encysted) PC but not SPC and these were described separately in the latest (4th) edition of the ‘WHO Classification of the Tumours of the Breast' [4], some cases show overlapping features [2]. EPCs may show solid areas and some SPCs show peripheral encapsulation and lack neuroendocrine differentiation.…”

“…Encapsulated and solid papillary carcinomas (EPCs and SPCs) of the breast are distinct histologic subtypes characterised by a well-defined, malignant, epithelial proliferation supported by fibrovascular stalks [1,2,3,4]. There is still controversy about the nature of papillary carcinoma (PC), but accumulating evidence indicates that PCs lacking myoepithelial cells have the biological potential to behave as an invasive disease with an expansile papillary growth pattern and indolent clinical behaviour.…”

Intracystic papillary carcinoma of the breast: A SEER database analysis of implications for therapy

“…Other theories consider IPC to be a tumor in transition from an in-situ to an invasive phase[10–12]. Despite the inconsistencies in establishing the true biological nature of these tumors, given their indolent nature, the WHO working group recommends classifying and treating them as them as Tis (in-situ carcinoma) for staging purposes, unless they have a clearly invasive component[8,13,14]. …”