Faculty Bibliography

A case of a 53-year-old woman with the epithelioid variant of mammary myofibroblastoma, which was initially misinterpreted as invasive lobular carcinoma, is presented. A needle core biopsy of the 1.6 cm mass showed interlacing bundles of epithelioid myofibroblasts amid dense fibrous tissue associated with lobular carcinoma in situ of the classical type. Most epithelioid cells showed nuclear atypia, and a few exhibited signet-ring cytology. Immunoreactivity for estrogen and progesterone receptors further compounded the deception, and the neoplasm was misinterpreted as invasive lobular carcinoma. Excisional biopsy showed a circumscribed stromal tumor with foci suspicious for invasive lobular carcinoma. The latter was excluded by cytokeratin negativity throughout the tumor. The overall histopathological appearance and immunostaining pattern was confirmatory of myofibroblastoma. This case report emphasizes the potential for mistaking epithelioid myofibroblastoma for invasive lobular carcinoma--particularly in the setting of limited sampling, hormone-receptor immunoreactivity of the lesional cells, and synchronous lobular carcinoma in situ.

Papillary thyroid carcinoma (PTC) is a common malignancy with multiple variants, some of which are rarely encountered in routine surgical pathology practice. PTC with exuberant nodular fasciitis-like stroma (PTC-NFS) or PTC with fibromatosis-like stroma (PTC-FMS) is one such variant. We report a case of PTC-NFS, a tumor characterized by an abundant stromal component with an intervening epithelial component with the typical morphologic features of conventional PTC. We review the literature on this rare variant, discuss the importance of a thorough search for epithelial components within any fibroproliferative lesion of the thyroid, and address the diagnostic difficulties created by the tumor's extensive stromal component.

AIMS/OBJECTIVE:Atypical ductal hyperplasia (ADH) rarely arises in gynaecomastia. We set out to understand more clearly the clinical, histological and immunohistochemical features of ADH in this setting. METHODS AND RESULTS/RESULTS:Twenty-five cases of ADH arising in gynaecomastia, nine cases of ductal carcinoma in situ (DCIS) and 36 cases of gynaecomastia with usual ductal hyperplasia (UDH) were studied. Reviews of clinical, morphological and immunohistochemical findings were performed. The extent of cytokeratin 5/6 (CK5/6) luminal epithelial cell staining was assessed (0% = 0, < 10% = 1, 10-50% = 2 and > 50% = 3). Oestrogen receptor (ER) was evaluated using the H-scoring system. The average age of ADH patients was 35 years (range 14-78). ADH was bilateral in 20% and less frequent in active gynaecomastia (24%). ADH often showed a cribriform pattern (72%), with less nuclear variation/size and similar frequency of mitoses than UDH cells. CK5/6 luminal epithelial staining was decreased in ADH (68%) versus UDH (11%). ADH showed high ER expression compared to UDH (H score > 270 in 88% and 14%, respectively). CONCLUSIONS:ADH in gynaecomastia can be distinguished from UDH by morphological and immunohistochemical features. We also identified a subset of young patients (< 25 years) with extensive bilateral ADH. More studies are needed to characterize this patient subset more clearly.

OBJECTIVES: The distinction between metastatic breast carcinomas (BCs) and primary lung carcinomas (PLCs) can be difficult. This study tested the utility of trefoil factor 1 (TFF1) for this purpose and compared it with mammaglobin and GATA protein binding 3 (GATA-3). METHODS: Tissue microarrays containing 365 BCs and 338 PLCs were stained with TFF1, mammaglobin, and GATA-3, and an H-score was calculated. Sensitivity, specificity, and accuracy were calculated, and logistical regression analysis was performed. RESULTS: Accuracy of correctly classifying the tumor type was 81.9%, 71.3%, and 64.0% for GATA-3, mammaglobin, and TFF1, respectively. Odds ratios for selecting BCs were 25.69, 93.15, and 4.17, respectively, with P values less than .001. With a single exception, the best immunopanel included GATA-3 and mammaglobin in all comparisons. CONCLUSIONS: TFF1 demonstrated breast specificity but was inferior to mammaglobin and GATA-3. Therefore, its routine clinical use may not be justified. TFF1 showed little benefit when added to an immunopanel.

INTRODUCTION: The purpose of the study was to determine predictors of recurrence for patients treated with neoadjuvant chemotherapy (NAC) and mastectomy according to the use of postmastectomy radiation therapy (PMRT). PATIENTS AND METHODS: An analysis of 161 clinically staged T1 to T3/N0 to N3 patients treated with NAC and mastectomy with and without PMRT at our institution from 2003 to 2010 was conducted. The Kaplan-Meier product limit method was used to estimate survival and time to recurrence rates and the log-rank test was used to compare groups. A Cox proportional hazard regression analysis was carried out for time to recurrence, radiation therapy, and their interaction in the model. RESULTS: The median follow-up period was 48 months and 18 patients developed a recurrence. The 5-year recurrence rate and overall survival was 16.1% (95% confidence interval [CI], 9.6%-26.3%) and 93.6% (95% CI, 88.2%-97.0%), respectively. Patients who underwent PMRT had a decreased risk of recurrence compared with patients who did not (hazard ratio [HR], 0.25; 95% CI, 0.097-0.661; P < .005). The 5-year disease-free survival (DFS) rate for those who received PMRT was 91.3% (95% CI, 82.8%-95.7%) and 64.8% (95% CI, 37.8%-82.4%) for those who did not (P = .0126). Among all clinicopathologic factors examined, pathologic T stage (ypT) and pathological N stage (ypN) significantly correlated with the risk of recurrence (P < .05). Patients with any pathological nodal disease had an increased risk of recurrence compared with patients who were pathologically node-negative (HR, 7.196; 95% CI, 2.05-25.264; P < .002). CONCLUSION: Patients treated with NAC and mastectomy, but without PMRT had a higher risk recurrence with increasing ypT and ypN stages. PMRT might increase DFS.

The abdominal mesenteries are important peritoneal structures that give rise to a wide spectrum of abnormalities, including solid mesenteric masses. Despite similarities in appearance, solid masses in the mesentery may have diverse etiologies, ranging from benign to highly malignant. While metastases are the most common cause of solid masses in the mesentery, other less common conditions are also important diagnostic considerations. This article reviews four pathologic entities (sclerosing mesenteritis, carcinoid tumors, desmoids tumors, and gastrointestinal stromal tumors) that may be manifested on abdominal imaging examinations by one or more mesenteric masses. These four pathologic entities are used to present a systematic approach to the radiographic characterization of solid mesenteric masses based on the morphology of the lesions, locoregional effects, and distant findings on various abdominal imaging examinations.

Breast cancer patients who receive radiation therapy or develop chronic lymphedema following axillary dissection can develop secondary mammary angiosarcomas (ASs) and, additionally, atypical vascular lesions (AVLs) in the former group. Recently, MYC amplification by fluorescence in situ hybridization (FISH) has been identified in secondary mammary AS but not in AVL and most primary mammary AS as well as AS of other sites. We studied MYC amplification and MYC protein expression in 7 radiation-induced AVLs, 9 secondary mammary ASs, 17 primary mammary ASs, and 20 primary ASs of other sites by FISH analysis and immunohistochemistry. All 9 secondary mammary ASs showed gene amplification and protein expression, whereas neither was found in any of 7 AVLs. No MYC amplification or protein expression was identified in any of the 17 primary mammary ASs. Among primary ASs of other sites, 1 cardiac AS and 1 skin AS showed gene amplification and protein expression. The remaining 18 did not show amplification (90%), but some demonstrated protein expression (39%). We conclude that MYC amplification by FISH is present in secondary mammary AS but not in AVL. We also found MYC amplification in 1 primary skin AS and 1 primary cardiac AS. There was 100% concordance between MYC amplification and protein expression in all AVL, primary mammary AS, and secondary mammary AS, whereas only 65% concordance was found in AS of other sites. MYC protein expression in AS can be helpful in certain diagnostic scenarios in the breast but not in other sites.

MRI of the breast is an increasingly employed modality for breast imaging due to its relatively high sensitivity for the detection of breast carcinoma. Cumulative data indicate that MRI of the breast has relatively higher sensitivity, but lower specificity than mammography. However, data regarding the diagnostic yield for particular types of breast lesions detected via breast MRI remain scant. Over a 3.5-year period, we evaluated histological findings of 192 needle core biopsies of MRI detected breast lesions. In this series, the positive predictive value of MRI detected lesions for breast carcinoma was 20%. Invasive carcinoma was diagnosed in 16/192 (8%) and in situ carcinoma in 22/192 (11%). The most commonly detected histological finding was cystic apocrine hyperplasia (19%), a benign entity.