[155] Clinical Outcome of Intracystic and Solid Papillary Carcinomas of the Breast

Roberto G Gamez, Sonia Narendra, Aziza Nassar. Mayo Clinic, Rochester, MN

Background: Papillary carcinoma (PC) of the breast accounts for 0.5 to 1% of breast cancer. The localized form of PC encompasses both the intracystic/encysted (IPC) and solid (SPC) variants, which are typically circumscribed and often encapsulated (separated from the surrounding mammary stroma by a fibrous capsule) and lack myoepithelial layer at their periphery. Hence the term encapsulated PC (EPC) has been introduced. IPC is usually confined to a dilated cystic space and is surrounded by a fibrous capsule. Compared to IPC, SPC is typically solid, characterized by mucin production and neuroendocrine features, and is more often multinodular. IPC and SPD have long been regarded as a form of in-situ carcinoma but the observation of the absence of a myoepithelial cells at the tumor stromal interface has led to the proposal that these lesions are, in fact, invasive carcinomas with an expansile growth pattern. This concept is supported by the results of some studies which reported cases of axillary nodal or distant metastases. The purpose of our study is to assess the clinical features, behavior and outcome of IPC and SPC in our population in regards to its clinical outcome in order to better understand the pathophysiology of these lesions.
Design: All cases of IPC and SPC were retrieved using SnoMed search from 1994 to 2011. The clinical-pathologic features including post-surgical treatment and outcome (recurrence, metastasis and death) were investigated and recorded. Descriptive and inferential analysis was performed.
Results: See Table 1.

Table 1. Results

Variables	IPC (21)	SPC (12)
Median age (mean)	68.7 (70.3)	72.2 (69.9)
Histologic grade	100 % low grade	91.7% low grade, 8.3% immediate grade
Mean tumor size (range)	1.4 cm (0.5- 2.5 cm)	1.8 cm (0.6 - 4.3)
Associated DCIS	38.1% (8/21)	25%(3/12)
Invasive ductal carcinoma IDC	33.3% (7/21)	50.0% (6/12)
Lymph node (LN) status (positive)	0.09% (1/11)	0.12% (1/8)
Reccurence	0.05% (1/21)	0
Mean folow up time (years)	4.2 (0-11)	1.5 (0.1-5.4)
Metastasis or death of disease	None	None

Conclusions: These lesions tend to occur in older women. Almost one third of the cases were accompanied by DCIS or IDC. Only patients with invasive disease developed LN metastasis, however recurrence is very rare and so its distant metastasis. As previously reported, these patients had excellent survival.
Category: Breast

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 46, Monday Morning