Rare, sporadic uterine leiomyomas arise in the setting of severe metabolic aberration due to somatic fumarate hydratase mutation. Germline mutations account for the Hereditary Leiomyomatosis and Renal Cell Carcinoma syndrome, which predisposes for cutaneous and uterine leiomyomas and aggressive renal cell carcinomas. Altered fumarate hydratase leads to fumarate accumulates in affected cells with formation of S-(2-succino)-cysteine, which can be detected with polyclonal antibody. High levels of these modified cysteine residues are found characteristically in fumarate hydratase-deficient cells, but not in normal tissues or tumors unassociated with Hereditary Leiomyomatosis and Renal Cell Carcinoma syndrome. We hypothesized that S-(2-succino)-cysteine-positive leiomyomas, indicating fumarate hydratase aberration, have morphologic features that differ from those without S-(2-succino)-cysteine positivity. Hematoxylin and eosin-stained slides of uterine smooth muscle tumors were prospectively analyzed for features suggesting Hereditary Leiomyomatosis and Renal Cell Carcinoma Syndrome, such as prominent eosinophilic macronucleoli with perinucleolar halos, yielding 9 cases. Germline genetic testing for fumarate hydratase mutations was performed in 3 cases. A detailed morphological analysis was undertaken, and S-(2-succino)-cysteine immunohistochemistry was performed with controls from a tissue microarray [leiomyomas (19), leiomyosarcomas (29), and endometrial stromal tumors (15)]. Of the 9 study cases, 4 had multiple uterine smooth muscle tumors. All cases had increased cellularity, staghorn vasculature, and fibrillary cytoplasm with pink globules. All cases had inclusion-like nucleoli with perinuclear halos (7 diffuse, 1 focal). All showed diffuse granular cytoplasmic labeling with the S-(2-succino)-cysteine antibody. Two of 3 tested patients had germline fumarate hydratase mutations. Only 1 leiomyoma from the tissue microarray controls was immunohistochemically positive, and it showed features similar to other immunohistochemically positive cases. Smooth muscle tumors with fumarate hydratase aberration demonstrate morphological reproducibility across cases and S-(2-succino)-cysteine immuno-positivity. Although the features described are not specific for germline fumarate hydratase mutation or the Hereditary Leiomyomatosis and Renal Cell Carcinoma syndrome, their presence should suggest fumarate hydratase aberration. Identifying these cases is an important step in the diagnostic workup of patients with possible Hereditary Leiomyomatosis and Renal Cell Carcinoma.

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Endometrial stromal sarcomas with the YWHAE-NUTM2A/B genetic fusion characteristically contain high-grade round to epithelioid cell component that is strongly and diffusely cyclin D1-positive and it may or may not show an associated low-grade fibroblastic/myxoid cell component. They are clinically more aggressive than endometrial stromal sarcomas with the JAZF1-SUZ12 genetic fusion and frequently demonstrate extrauterine extension at initial clinical presentation. In this setting, the tumor may be misdiagnosed as gastrointestinal stromal tumor. This study examines the expression of KIT and ANO1 in 14 YWHAE-NUTM2A/B tumors by immunohistochemistry. Staining localization was determined as membranous and/or cytoplasmic, and the staining intensity was assessed (negative, weak, moderate and strong). Of the 14 tumors, 6 contained only a high-grade round cell component, 2 only a low-grade fibroblastic component and 6 had both components in the slides evaluated. The high-grade round cell component displayed moderate to strong membranous/cytoplasmic KIT staining in all tumors (12 of 12). The low-grade fibroblastic cell component showed only weak cytoplasmic KIT staining in 3 of 8 tumors. In contrast, ANO1 was negative in all 14 neoplasms, irrespective of the component evaluated. Sanger sequencing analysis (exons 9, 11, 13 and 17) and Ampliseq Cancer Panel mutation screen (Ion Torrent) demonstrated no KIT mutations in three KIT-positive YWHAE-NUTM2A/B tumors. This study shows that the high-grade round cell component of YWHAE-NUTM2A/B endometrial stromal sarcoma consistently expresses KIT but lacks KIT hotspot mutations. KIT expression may represent a potential diagnostic pitfall in the evaluation of YWHAE-NUTM2A/B endometrial stromal sarcoma presenting with pelvic/ abdominal mass, particularly in situations where its uterine origin is not definitive, and thus a panel of antibodies that includes ANO1 and cyclin D1 is necessary.

Adenoid cystic, mucoepidermoid, and polymorphous low-grade carcinomas of the breast express immunohistochemical markers that characterize the intrinsic basal-like subtype of breast cancer.

Background:Automated whole slide imaging (WSI), also known as virtual microscopy is rapidly becoming an important tool in diagnostic pathology. Currently, the primary utilization of the technique is for transmission of digital images, for second opinion consultation, as well as for quality assurance and education. The high-resolution of digital images along with the refinement of technology could now allow for WSI to be used as an alternative to conventional microscopy (CM) as a first line diagnostic platform. However, the accuracy and reproducibility of the technology for the routine histopathologic diagnosis has not been established yet. This study was undertaken to compare the intra-observer variability of WSI and CM in the primary diagnosis of breast biopsies.Materials and Methods:One hundred and three consecutive core needle biopsies of breast were selected for this study. Each slide was digitally scanned and the images were stored in a shared file. Three board-certified pathologists independently reviewed the glass slides by CM first, and in an interval of 2-3 weeks for the 2nd time to establish their baseline CM versus CM reproducibility. They then reviewed the digital images of all cases following the same interval of time to compare the reproducibility of WSI versus CM for each observer. The diagnostic categories included the typical range of benign and malignant mammary lesions.Results:The intra-observer variability for CM versus CM was 4%, 7%, and 0% for observers 1, 2, and 3 respectively. The diagnostic variability for WSI versus CM was 1%, 4%, and 1% for the same observers. All diagnostic disagreements were between ductal hyperplasia and atypical ductal hyperplasia. There was no intra-observer disagreement in the diagnosis of benign versus malignant disease.Conclusions:The intra-observer variability in the diagnosis of the core needle biopsies of the breast by high-resolution, WSI was the same as conventional glass slide microscopy. These results suggest that, WSI could be used similar to CM for the initial diagnosis of breast biopsies.

Background: Alloimmunization is an adverse effect of blood transfusions. In Chile, alloimmunization frequency is not established, and for this reason the aim of this study was to investigate the prevalence and specificity of red blood cell (RBC) alloantibodies in Chilean transfused subjects. Methods: Records from 4,716 multi-transfused patients were analyzed. In these patients, antibody screening was carried out prior to cross-matching with a commercially available two-cell panel by the microcolum gel test, and samples with a positive screen were analyzed for the specificity of the alloantibody with a 16-cell identification panel. Results: The incidence of RBC alloimmunization in transfused patients was 1.02% (48/4,716) with a higher prevalence in women (40/48). We detected 52 antibodies, the most frequent specificities identified were anti-E (30.8%), anti-K (26.9%), anti-D (7.7%), and anti-Fy^a (5.8%). The highest incidence of alloantibodies was observed in cancer and gastroenterology patients. Conclusion: The data demonstrated a low alloimmunization frequency in Chilean transfused patients, principally associated with antibodies anti-E, anti-K, anti-D, and anti-Fy^a.

Given the low rate of well differentiated HER2 positive tumors, falling within the range reported for false negative IHC tests for HER2, and the absence of published data demonstrating a beneficial effect of trastuzumab therapy in this subset of patients, HER2 testing should not be considered a standard of care for all patients with well-differentiated breast cancer.

Mammaglobin A (MG-A) is purportedly useful for detecting metastatic carcinomas suspected to be of breast origin and has been advocated as a useful marker of micrometastasis in sentinel lymph nodes and minimal residual tumor in bone marrow. Little is known about its expression frequency in histologic subtypes of breast cancer. Excisional biopsy specimens from 1,079 untreated invasive mammary carcinomas were evaluated for immunohistochemical expression of MG-A. In addition to estrogen (ER) and progesterone receptors (PR) and HER2, staining for p63 and HLA-DR was used to further characterize histologic subtypes. Of the carcinomas, 36 were classified as metaplastic (based on morphologic features, ER-/PR-/HER2-, p63+), 38 as medullary (ER-/PR-/HER2-, HLA-DR+), and 1,005 as ductal, no special type (NST). All metaplastic and medullary carcinomas were negative for MG-A. Of 1,005 ductal carcinomas, NST, 492 (49.0%) were MG-A+, 62.0% with a reaction in fewer than 25% of the cells. MG-A immunohistochemical studies failed to detect all medullary and metaplastic cancers and more than 50% of ductal carcinomas, NST. In two thirds of MG-A+ ductal carcinomas, the reaction was only focal and usually in a minority of cells. These findings suggest that MG-A has limited value in identifying the mammary origin of carcinomas, particularly in small biopsy specimens used to detect metastasis or minimal residual disease.