[217] Invasive Pleomorphic Lobular Carcinoma: A Clinicopathologic and Immunohistochemistry Study of 40 Cases.

LaKeta Monhollen, Carl Morrison, Foluso Ademuyiwa, Rameela Chanddrasekhar, Gregory Wilding, Thaer Khoury. Roswell Park Cancer Institute, Buffalo, NY

Background: Invasive pleomorphic lobular carcinoma (PLC) is a rare aggressive variant of invasive lobular carcinoma. Given its rarity, the clinicopathologic features of this entity are not well studied. It has been reported that this type is a good responder to trastuzumab. The purpose of this study was to review its clinicopathologic findings.
Design: Cases were collected from the clinical database and pathology department search engine in Roswell Park Cancer Institute from 1995 to 2010. Cases were either in house or referred from another hospital. Histologic features were reviewed including SBR grade, percentage of grade 3 nuclei (>10% was required to consider tumor pleomorphic), in situ component (ductal or lobular), histologic pattern, margin status, and lymphovascular invasion. Cases with available tissue blocks were constructed in tissue microarray (TMA) blocks (n= 34). E-cadherin, estrogen receptor, progesterone receptor, and HER2 by fluorescence in situ hybridization were performed on the TMA slides. Other clinicopathologic data were also collected including tumor size and stage, nodal status, therapy modality, disease free and overall survival. Fisher's exact test and Logrank test were used for statistical analysis.
Results: There were 43 cases that met our criteria. There 29 SBR grade 2 and 14 SBR grade 3. There were 5 histologic patterns (18 classic, 13 mixed, 1 nested, 8 solid, and 3 trabecular). Hormone receptors were negative in 7 (16.3%) cases and positive in 31 (72.1%) cases (5 cases had no hormone receptors data). HER2 was amplified in 10 (23.3%) cases and negative in 31 (72.1%) cases (2 cases had no HER2 data). Clinically, 9 patients had local recurrence and 10 died of disease with median follow-up of 47.7 (1.84-156.57) months. Two patients were treated with trastuzumab and 24 patients received adjuvant chemotherapy. One patient that was treated with trastuzumab developed tumor recurrence in 2 years. There was no correlation between any of the clinicopathologic parameters and clinical outcome.
Conclusions: Although PLC is a morphologic form of lobular carcinoma, it has features of ductal carcinoma NOS. It might not differ in terms of trastuzumab response from other type.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 54, Monday Afternoon


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