[107] Florid Lobular Intraepithelial Neoplasia (FL-LIN) with Signet Ring Cells (SRC), Central Necrosis and Calcifications: A Clinicopathologic and Immunohistochemical Analysis of Ten Cases

I Alvarado-Cabrero, R Valencia-Cedillo, S Barroso-Bravo. Mexican Oncology Hospital, Mexico, DF, Mexico

Background: In the most florid type of ductal involvement, LIN proliferates to form a solid mass of tumor cells that fill and expand the duct lumen. Foci such as these can develop central necrosis and calcifications, which are detectable on mammograms. The immunohistochemical expression of E-cadherin has been found to be absent in virtually all reported examples of LIN with necrosis. FL-LIN with necrosis may consist of classical or pleomorphic cell types. However, the occurrence of LIN composed entirely of signet ring cells with central necrosis is extraordinarily rare. We describe herein 10 examples of these cases, to illustrate this uncommon morphologic pattern of Lobular Intraepithelial Neoplasia.
Design: The cases were encountered during routine clinical practice of the authors performed over a 5-year period (2002-2007) at Mexican Oncology Hospital. In all cases, we analized the expression of E-cadherin(E), high-molecular-weight keratins (HMWK), Estrogen Receptor (ER), Progesteron Receptor (PR) and Her2/neu. Patients clinical information was obtained from the medical records.
Results: We reviewed 10 patients with florid LIN with SRC and central necrosis, patients ranged in age from 45 to 75 years (mean:51.2). Clinical profiles of patients were not significant different from those with classical LIN. The main indications for biopsy were calcifications (n:7) and mass (n:3). On mammography, all calcifications were clustered, punctuate, high density and smaller than or equal to 0.6mm. Luminal necrosis was present in all cases and calcifications in 7 of FL-LIN with SRC. Eight patients (80%) had associated invasive carcinoma including 5 classical lobular, and 3 invasive lobular carcinoma classical type with signet ring cells. Immunoreactivity for ER, PR and HMWK was present in 9/10(90%), 8/10(80%) and 9/10(90%) of cases respectively. All cases had complete absence of staining for E. Overexpression of Her 2/neu was absent in all 10 cases.
Conclusions: Lobular Intraepithelial Neoplasia composed entirely of signet ring cells can develop extreme ductal and lobular enlargement, central necrosis and calcifications. These cases are frequently associated with invasive lobular carcinoma.
Category: Breast

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 38, Tuesday Morning