ABSTRACT
PURPOSE: Infiltrating lobular carcinoma (ILC) represents approximately 10% of all breast cancers. Its detection and staging for appropriate surgical planning may be difficult on account of its unique growth pattern, including a linear file arrangement of the tumor cells and a planar growth pattern and the resulting low density of the lesions. The purpose of this study was to evaluate the clinicopathological features of an ILC of the breast including multifocality, the preoperative accuracy of the pathological diagnostic tools, and its impact on the surgical procedure. METHODS: Between 1997 and 2003 at the Asan Medical Center, a group of 63 patients with a pathologically proven invasive lobular carcinoma who had undergone surgery were included. They were all in stage I~III, and their medical records, mammographic and sonographic results, and pathologic findings were reviewed retrospectively. RESULTS: Of the 63 patients with a mean age of 48 years (range 35 to 70), multifocal lesions were identified in 27.0% by a pathological examination. For a preoperative evaluation of a multifocal lesion, the sensitivity and positive prediction value were 21.4% and 50% by mammography, and 92.9% and 52.0% by ultrasonography, respectively. Only 27.0% of all patients were confirmed as having an ILC preoperatively; surgical excision or incision biopsies 75%, core-needle biopsy 36.4%, frozen biopsy 22.7%, FNA 5.9%. Conservative surgery was performed in only 14.3% and a mastectomy was performed on 85.5%. The mean tumor size was 3.0 cm, and according to the TNM stage, stage I was found in 22.2%, stage II in 58.7%, stage III in 19.1%. ER-positive was found in 83.9% and PR-positive was found in 74.2%. Seven out of 11 patients, who underwent the planed conserving surgery, had a positive resection margin, 1 case had re- excision, 2 cases underwent mastectomies, and 4 cases underwent radiation therapy without additional surgery. CONCLUSION: Since invasive lobular carcinomas have more often multifocal lesions and a preoperative accurate evaluation may be difficult pathologically or radiologically, a careful evaluation of the accurate tumor extent as well as the multifocal lesion is needed particularly for patients with an ILC considering conserving surgery.