Faculty Bibliography

In diagnostic breast pathology, there is no reliable applicable immunostain to help discern atypical and in situ apocrine lesions from benign apocrine tissue. At present, the diagnosis of non-invasive apocrine lesions remains challenging with current diagnoses rendered based on discrete morphologic characteristics on conventional hematoxylin and eosin staining. Interobserver variability is significant even among subspecialists partly due to lack of adjuvant diagnostic immunohistochemical stains. Herein, we set to elucidate the potential utility of EZH2 and Ki-67 immunostains as tangible tools in non-invasive apocrine proliferations. A cohort of apocrine breast lesions [Benign apocrine hyperplasia (BAH), n = 10; Atypical apocrine hyperplasia (AAH), n = 16; Apocrine ductal carcinoma in situ (ADCIS), n = 12] were subjected to EZH2 immunostaining and analyzed via H-scoring of nuclear expression. Mean H-scores for EZH2 progressively increased from BAH (23.5), to AAH (47.4) and ADCIS (196.4), and showed a significant difference utilizing the Kruskal-Wallis test (p < 0.0001). Further interrogation of Ki-67 demonstrated incremental expression from BAH to AAH and ADCIS at 1.6 %, 4.7 % and 24.7 %, respectively (p < 0.0001, Kruskal-Wallis test), suggesting an association with increased proliferation. Our results demonstrate that a combination of EZH2 and Ki-67 immunostaining may be employed in differentiating among challenging apocrine breast lesions and suggest a putative diagnostic utility for EZH2 and Ki-67 in non-invasive apocrine breast lesions.

Background: Diagnosis of microinvasion (MI) in breast core needle biopsy (CNB) can be challenging particularly in a background of carcinoma in situ (CIS) involving sclerosing lesion with periductal fibrosis and lymphocytic infiltrate. Immunohistochemical stains (IHC) for myoepithelial cells aid in confirming MI. Surgical management of MI deviates from CIS as the former includes sentinel lymph node biopsy (SLNB) while the latter typically includes SLNB only when total mastectomy (TM) is planned. We investigated the utility of IHC in diagnosing MI in our CNBs and its impact on final histopathology on surgical excision.
Design(s): We conducted a search for cases of CIS with foci suspicious for MI, in which IHC for calponin and p63 was used to confirm MI (defined as invasive carcinoma <=1 mm) between January 2010 and June 2019. CIS included ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). MI cases diagnosed based on routine histology were also collected for the same time period. Only cases with follow up excision data were included. Cases with synchronous invasive carcinoma were excluded. Clinicopathologic data including age, size, laterality, resection type, SLNB status and biomarker profiles were compared. Graphpad Prism software was used for statistical analysis.
Result(s): We identified 106 cases of CIS (102 DCIS, 4 LCIS), where IHC was used to confirm MI (MI-IHC hereafter). Mean age was 58 years. Of the 106 cases MI-IHC was identified in 24 cases (23%). See table. All 24 MI-IHC cases had SLNB (100%). Of the 82 CIS cases, 39 had SLNB (48%). Relative risk of finding invasive carcinoma/MI on resection in MI-IHC was 1.8 (p=0.03) compared to CIS. There was no correlation between the biomarker profile with the resection outcome in either CIS (p=0.5, Fisher's exact test) or MI-IHC cases (p=3.4, Chi-square test). We identified 7 cases of MI, diagnosed on routine histology without IHC, of which 5 (71%) had invasive carcinoma/MI and 2 (29%) had CIS or no residual carcinoma on resection. Mean size of invasive carcinoma and CIS on resection in this group was 11 mm and 25 mm, respectively. The resection outcome between MI-IHC and MI based on routine histology was not significant (p=0.6). (Table presented)
Conclusion(s): IHC helped diagnose MI in CNB for CIS in 23% of cases. Compared to CIS, the diagnosis of MI-IHC carried a relative risk of 1.8 in finding invasive carcinoma/MI on resection. There was no difference in the significance of the method used for the diagnosis of MI

Background: Intraoperative evaluation of the nipple/subareolar tissue (N/SAT) has been used by surgeons to assess for occult nipple involvement by malignancy and guide the decision-making process for nipple preservation during nipple sparing mastectomies (NSM). The aim of our study is to evaluate significance and accuracy of frozen section (FS) results compared to final pathology/permanent sections.
Design(s): We retrospectively reviewed records of patients that underwent NSM with FS of the N/SAT from 2014 to 2018. Positive FS or final pathology results include atypical hyperplasia, in situ and invasive carcinoma.
Result(s): Over a 5-year period a total of 339 NSM cases utilized FS to evaluate the N/SAT. Of the total 339 cases, 85(25%) were prophylactic and 254(75%) were therapeutic mastectomies. All 85 prophylactic mastectomies were negative (benign) on FS and final diagnosis. Among 254 therapeutic mastectomies, 217(85.4%) showed negative (benign) intraoperative FS with concordant benign final pathology; 22(8.7%) showed positive intraoperative FS with concordant positive final pathology; 15(5.9%) were false negative (benign) on FS and positive on final permanent sections (figure 1). Positive results consisted of atypical ductal or lobular hyperplasia (5, 27.8%), in situ ductal or lobular carcinoma (11, 61.1%) and invasive carcinoma (1, 5.6%). One false positive case showed "atypical intraductal proliferation" at FS and was diagnosed as intraductal papilloma on final pathology; the nipple was not removed at the time of surgery. Of the 37 cases with positive final nipple pathology, 14(37.8%) had intraoperative resection of the nipple/areola complex (NAC), 9(24.3%) required an additional surgery for removal of NAC and 13(35.1%) had no additional procedures performed. Residual pathology was identified in 9(39.1%) of the resected NAC. In our patient cohort frozen section diagnosis has a sensitivity of 58.3%, specificity of 99.5%, positive predictive value (PPV) of 95.5% and negative predictive value (NPV) of 93.5%. (Figure presented)
Conclusion(s): Intraoperative evaluation of the N/SAT is highly accurate (93.7%) and specific (99.5%) test that prevented additional surgical intervention in 8.7% of therapeutic mastectomies. At the same time, surgeons should be aware of the low/moderate sensitivity of intraoperative FS, which may be explained by processing artifacts, sampling or cautious approach not to overcall the FS findings

Background: The Mediator Complex (MED) is a large multi-subunit protein which interacts directly with RNA Polymerase II and transcription factors for general regulation of protein expression. Recently, Mediator Complex 7 (MED7) has been shown to be underexpressed in high grade invasive mammary carcinomas in comparison to lower grade invasive carcinomas. No study has yet investigated the expression of MED7 in ductal carcinoma in situ (DCIS). In our study, we set out to evaluate the biological significance of MED7 in DCIS.
Design(s): MED7 immunostaining was performed with a rabbit monoclonal antibody (EPR15410, Abcam- Ab187146, Cambridge, UK). The H-score method was utilized for quantifying MED7 nuclear expression in DCIS. This method combines nuclear staining intensity and the percentage of positive cells. Staining intensity (0-3) is multiplied by percentage of positive DCIS cells (0-100) leading to the H-score, with a range of 0-300 for each case. We investigated breast core biopsies with DCIS; 20 were high grade, 14 were intermediate grade, and 15 were low grade. The hormone receptor status of each case was also recorded. GraphPad PRISM 7.0 software was used for statistical analysis.
Result(s): The mean H-Score for high grade DCIS cases was 146, intermediate grade was 219, and low grade was 228 (p <0.0001, Kruskal-Wallis test). The mean H-score for high grade DCIS cases was significantly lower than that of low and intermediate grade DCIS (p <0.0001 and p = 0.0004, respectively, Dunn's test). The MED7 H-Score was significantly lower in ER negative cases compared to that seen in ER positive cases (p <0.0001). Area under the curve (AUC) in the ROC curve for MED7 H-Scores in high grade versus non-high grade DCIS cases was 0.9276 (p <0.0001). (Table presented)
Conclusion(s): Our results suggest that MED7 expression is significantly down regulated in high grade and ER-negative DCIS cases, thus implying a significant biological role of MED7 in the progression of DCIS. Taken together, our data establishes MED7 H-score as a tangible tool for evaluating high grade DCIS. Further studies are underway to establish a practical cut-off value for the MED7 H-Score for high grade DCIS. We believe that these important early steps investigating MED7 are crucial in clarifying its important role in the development and progression of breast and other cancers

CONTEXT.—/UNASSIGNED:Bilateral mastectomy for chest masculinization is one of the gender-affirming procedures for transmasculine individuals. OBJECTIVE.—/UNASSIGNED:To optimize gross handling protocols and assess histopathologic findings in transmasculine breast tissue specimens. DESIGN.—/UNASSIGNED:We identified all gender-affirming mastectomies from 2015 to 2018. We sequentially identified reduction mammoplasty (RM) cases for macromastia from the same period as control. Significant findings were defined as atypical ductal or lobular hyperplasia (ADH, ALH), ductal or lobular carcinoma in situ (DCIS, LCIS), or invasive carcinoma. RESULTS.—/UNASSIGNED:Significant findings were present in 6 of 211 gender-affirming mastectomies (2.8%) as follows: ADH (n = 5) and LCIS together with ALH (n = 1). By comparison, 19 of 273 RM specimens (7%) yielded significant findings as follows: ALH (n = 11), ADH (n = 4), LCIS (n = 2), DCIS (n = 1), and invasive lobular carcinoma (n = 1). In the gender-affirming group, 142 transmen underwent androgen therapy before surgery, of whom 2 had significant pathologic findings. Thirty and 41 individuals had a family history of breast cancer in the gender-affirming and RM group, of whom 1 and 3 individuals had significant pathologic findings, respectively. CONCLUSIONS.—/UNASSIGNED:Our study demonstrates that we handle transmasculine mastectomy specimens by examining 2.8 times more slides on average than for RMs, with a 2.5 times lower rate of significant pathologic findings. Prior family history of breast cancer or the use of androgen therapy before surgery in gender-affirming individuals did not increase the risk of identifying significant breast lesions. We recommend submitting 4 tissue blocks per mastectomy for individuals undergoing gender-affirming breast surgery.

Amyloidosis is characterized by extracellular deposition of insoluble protein fibrils in a beta-pleated sheet configuration. Breast amyloidosis is a rare entity which has previously been reported to present with localized involvement, or as a late manifestation of systemic amyloidosis. However, descriptions of the clinicopathologic features of localized breast amyloidosis remain limited. A retrospective search for breast amyloidosis diagnosed at our institution yielded 10 cases of breast amyloidosis. All patients were female, with a mean age of 69. Median follow-up for survival or progression was 13 months. Indications for breast or axilla biopsy included mammographic calcifications, mass, and axillary lymphadenopathy. Amyloid showed positive staining with Congo red in all cases, and amyloid typing revealed light chain lambda in 3 cases, amyloid transthyretin in 2 cases, light chain kappa in 1 case, and iatrogenic insulin-derived amyloidosis in 1 case. Amyloid occurred within axillary lymph nodes and alongside both benign and neoplastic breast tissue, including atypical ductal hyperplasia, lobular carcinoma in situ and ductal carcinoma in situ. Most cases were associated with predisposing clinical conditions, including autoimmune disease in 4 cases, B cell lymphomas in 2 cases, and diabetes mellitus treated with insulin in 1 case. In contrast to previously published case series, no patient had clinical evidence of systemic amyloidosis. Amyloidosis of the breast should be considered in the differential diagnosis of all mammographic calcifications and masses of the breast or axilla. When recognized correctly on biopsy, the diagnosis of amyloidosis can not only prevent further unnecessary surgical interventions due to radiology-pathology discordance, but initiate the necessary amyloidosis work-up. Although rare, an awareness of the clinicopathologic characteristics of this easily overlooked entity is of great importance for every practicing pathologist reviewing breast biopsies.