To identify the minimum time necessary for consistent immunohistochemical estrogen receptor (ER) results in our laboratory, we evaluated results in timed fixation blocks and cases with disparate and similar needle core biopsy and partial mastectomy specimens. Tissue sections of 24 ER-positive, invasive breast carcinomas were fixed for 3, 6, 8, and 12 hours and 1, 2, and 7 days. ER values were quantified using the Q score (0-7). In timed fixation blocks, the mean Q score per block was 2.46 for blocks fixed for 3 hours, 5.75 for blocks fixed for 6 hours, and 6.70 for blocks fixed for 8 hours (P < .001). The difference between the case maximum and mean block Q scores was a plateau of almost 0 at 6 to 8 hours of formalin fixation. For needle core biopsy specimen fixation times, the means for specimens with ER-disparate and ER-similar results were 1.2 and 6.3 hours, respectively (P = .01). The minimum formalin fixation time for reliable immunohistochemical ER results is 6 to 8 hours in our laboratory, regardless of the type or size of specimen.

To identify the minimum time necessary for consistent immunohistochemical estrogen receptor (ER) results in our laboratory, we evaluated results in timed fixation blocks and cases with disparate and similar needle core biopsy and partial mastectomy specimens. Tissue sections of 24 ER-positive, invasive breast carcinomas were fixed for 3, 6, 8, and 12 hours and 1, 2, and 7 days. ER values were quantified using the Q score (0-7). In timed fixation blocks, the mean Q score per block was 2.46 for blocks fixed for 3 hours, 5.75 for blocks fixed for 6 hours, and 6.70 for blocks fixed for 8 hours (P < .001). The difference between the case maximum and mean block Q scores was a plateau of almost 0 at 6 to 8 hours of formalin fixation. For needle core biopsy specimen fixation times, the means for specimens with ER-disparate and ER-similar results were 1.2 and 6.3 hours, respectively (P = .01). The minimum formalin fixation time for reliable immunohistochemical ER results is 6 to 8 hours in our laboratory, regardless of the type or size of specimen.

We studied 31 T1 N0 M0 peripheral adenocarcinomas diagnosed by wedge resection and treated by lobectomy. Factors recorded were pleural surface-based, gross cut-surface, and microscopic margin distances; morphologic features of the adenocarcinomas; microscopic extension distance of beyond gross perimeter of neoplasm; and presence of residual adenocarcinoma in the lobectomy specimen. All staple-line margins in the wedge and lobectomy specimens underwent complete histologic examination. The mean pleural surface-based, gross cut-surface, and microscopic margin distances in wedge resections were 13.1, 4.1, and 2.3 mm, respectively. The mean microscopic wedge resection margin distance was 11 mm smaller than the pleural surface-based measured margin. The mean microscopic lepidic growth beyond the gross perimeter of the neoplasm was 7.4 mm. Fourteen lobectomy specimens (45%) included adenocarcinoma. The mean microscopic wedge resection specimen margin distances in cases with and without residual adenocarcinoma in the lobectomy specimens were 0.7 and 2.4 mm, respectively (P < .001). Incomplete excision may contribute to higher locoregional recurrence rates following limited resection surgery. Two processes affected wedge resection margin distances: stapling-induced parenchymal stretching, resulting in overestimation of pleural surface-based distances, and microscopic extension of adenocarcinoma beyond the gross perimeter of the neoplasm.

We studied 31 T1 N0 M0 peripheral adenocarcinomas diagnosed by wedge resection and treated by lobectomy. Factors recorded were pleural surface-based, gross cut-surface, and microscopic margin distances; morphologic features of the adenocarcinomas; microscopic extension distance of beyond gross perimeter of neoplasm; and presence of residual adenocarcinoma in the lobectomy specimen. All staple-line margins in the wedge and lobectomy specimens underwent complete histologic examination. The mean pleural surface-based, gross cut-surface, and microscopic margin distances in wedge resections were 13.1, 4.1, and 2.3 mm, respectively. The mean microscopic wedge resection margin distance was 11 mm smaller than the pleural surface-based measured margin. The mean microscopic lepidic growth beyond the gross perimeter of the neoplasm was 7.4 mm. Fourteen lobectomy specimens (45%) included adenocarcinoma. The mean microscopic wedge resection specimen margin distances in cases with and without residual adenocarcinoma in the lobectomy specimens were 0.7 and 2.4 mm, respectively (P < .001). Incomplete excision may contribute to higher locoregional recurrence rates following limited resection surgery. Two processes affected wedge resection margin distances: stapling-induced parenchymal stretching, resulting in overestimation of pleural surface-based distances, and microscopic extension of adenocarcinoma beyond the gross perimeter of the neoplasm.