Fit-for-Purpose Ki-67 Immunohistochemistry Assays for Breast Cancer.

New therapies are being developed for breast cancer, and in this process, some "old" biomarkers are reutilized and given a new purpose. It is not always recognized that by changing a biomarker's intended use, a new biomarker assay is created. The Ki-67 biomarker is typically assessed by immunohistochemistry (IHC) to provide a proliferative index in breast cancer. Canadian laboratories assessed the analytical performance and diagnostic accuracy of their Ki-67 IHC laboratory-developed tests (LDTs) of relevance for the LDTs' clinical utility. Canadian clinical IHC laboratories enrolled in the Canadian Biomarker Quality Assurance Pilot Run for Ki-67 in breast cancer by invitation. The Dako Ki-67 IHC pharmDx assay was employed as a study reference assay. The Dako central laboratory was the reference laboratory. Participants received unstained slides of breast cancer tissue microarrays with 32 cases and performed their in-house Ki-67 assays. The results were assessed using QuPath, an open-source software application for bioimage analysis. Positive percent agreement (PPA, sensitivity) and negative percent agreement (NPA, specificity) were calculated against the Dako Ki-67 IHC pharmDx assay for 5%, 10%, 20%, and 30% cutoffs. Overall, PPA and NPA varied depending on the selected cutoff; participants were more successful with 5% and 10%, than with 20% and 30% cutoffs. Only 4 of 16 laboratories had robust IHC protocols with acceptable PPA for all cutoffs. The lowest PPA for the 5% cutoff was 85%, for 10% was 63%, for 20% was 14%, and for 30% was 13%. The lowest NPA for the 5% cutoff was 50%, for 10% was 33%, for 20% was 50%, and for 30% was 57%. Despite many years of international efforts to standardize IHC testing for Ki-67 in breast cancer, our results indicate that Canadian clinical LDTs have a wide analytical sensitivity range and poor agreement for 20% and 30% cutoffs. The poor agreement was not due to the readout but rather due to IHC protocol conditions. International Ki-67 in Breast Cancer Working Group (IKWG) recommendations related to Ki-67 IHC standardization cannot take full effect without reliable fit-for-purpose reference materials that are required for the initial assay calibration, assay performance monitoring, and proficiency testing.

Hypertensive crisis precatheter ablation for resistant atrial fibrillation: a case of undiagnosed bilateral pheochromocytomas.

A 63-year-old man with hypertension was referred for catheter ablation of persistent atrial fibrillation. He was diagnosed with paroxysmal atrial fibrillation approximately 6 years prior. Over the previous 12 months, his atrial fibrillation had become persistent despite medication optimisation for rate control and elective cardioversion. Sinus rhythm was restored briefly. The decision was made to pursue catheter ablation and isolation of the pulmonary veins. On anaesthetic induction, the patient suffered from a hypertensive crisis. The procedure was aborted, and the patient was admitted to hospital for investigations of secondary hypertension. Ultimately, the patient was diagnosed with bilateral pheochromocytomas. This case outlines the diagnostic challenges and cardiac comorbidities associated with bilateral pheochromocytomas.

Diagnostic Variation in p53 Usage for Endometrial Carcinoma Diagnosis: Implications for Molecular Subtyping.

Immunostaining for p53 is widely but variably used when diagnosing endometrial carcinoma (EC). Mutant-pattern p53 staining can support a diagnosis of serous carcinoma, and also serve as a surrogate test for identifying the "serous-like" subset of aggressive EC identified by The Cancer Genome Atlas characterized by high numbers of somatic copy number abnormalities. We, retrospectively, assessed WHO histotype, usage of p53 immunostaining, and p53 status in a consecutive series of biopsies showing EC from a single hospital. Of 79 ECs, 59 (75%) were low-grade EC (LGEC), 13 (16%) high-grade EC (HGEC), and 7 (9%) were serous. p53 immunostaining was performed at the time of diagnosis in 27/79 (34%) biopsies; 6/7 of serous histotype, 11/13 HGEC, and 10/59 LGEC. Mutant-pattern p53 staining was present in 6/6 serous, 2/11 HGEC, and 2/10 LGEC. The remaining 53 tumors subsequently had p53 immunostaining done; all 49 LGEC showed wild-type staining and the serous carcinoma and 1/2 HGEC showed mutant pattern staining. While there are no guidelines on using p53 in endometrial biopsies, this study shows consistent usage in high-grade histotypes and variable usage in LGEC. As 100% (7/7) of serous EC and 3% (2/59) of the LGECs showed mutant-pattern p53 staining, histotype may serve as a surrogate for p53 assessment, such that only HGEC or ambiguous carcinomas should be routinely subjected to p53 immunostaining.

Targeted Molecular and Immunohistochemical Analyses of Endometrial Clear Cell Carcinoma Show that POLE Mutations and DNA Mismatch Repair Protein Deficiencies Are Uncommon.

Endometrial clear cell carcinoma (ECCC) is an uncommon histotype without unique identified molecular alterations. Recently, The Cancer Genome Atlas molecular subtypes have been reported in ECCC. ECCC cases were collected from 11 institutions with diagnoses confirmed by morphologic review and immunohistochemistry. DNA mismatch repair (MMR) proteins, p53 expression, and ARID1A expression was assessed by immunohistochemistry on tissue microarrays. Targeted next-generation sequencing was completed for POLE, TP53, KRAS, and PIK3CA. Pathogenicity of mutations was determined using MutationTaster and PolyPhen databases. For p53, immunohistochemistry and sequencing were complimentarily used to assess the p53 status. Of 57 cases, 46 were considered prototypical ECCC by morphology and immunohistochemical profile (Napsin A-positive and ER-negative). Three cases were excluded because of insufficient sample for complete immunohistochemical analysis, and 6 had failed sequencing, resulting in 37 cases. Of the 37 remaining cases, 6/37 (16%) had predicted pathogenic mutations in the exonuclease domain of POLE with an allelic frequency >10%; however, no hot-spot mutations were identified. No cases were MMR-deficient. The gene most commonly affected was TP53 (59%, 22/37), followed by KRAS (13%, 2/15) and PIK3CA (13%, 2/15). The current study is the largest molecular analysis of pure ECCC reported to date. When strict classification criteria are applied, MMR-deficient and POLE mutated subtypes are not represented. Further consensus on what represents a deleterious POLE mutations is needed. The findings support separately studying histologically/immunohistochemically defined ECCC to identify characteristic molecular alterations in future studies.

Extrapelvic Metastases in Endometrial Stromal Sarcomas: A Clinicopathological Review With Immunohistochemical and Molecular Characterization.

Endometrial stromal sarcoma is a rare uterine tumor associated with favorable outcomes despite its ability to recur and metastasize to distant sites. Most recurrences are local, being limited to the abdomen/pelvis, but distant metastases can occur. Metastatic endometrial stromal sarcoma can occur many months to years after the original diagnosis or may present prior to the primary, potentially creating a diagnostic challenge. We report a bi-institutional review of 10 cases of endometrial stromal sarcoma with extrapelvic metastases without a prior history of endometriosis. The histologic, immunophenotypic, and molecular characteristics of these tumors are analyzed in the context of a relevant literature review.

An Epithelioid Gastrointestinal Stromal Tumor of the Stomach With Strong Expression of Keratin: Clinicopathologic Correlation and Follow-up Post-Imatinib Therapy.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasms of the digestive tract. They are relatively rare neoplasms compared with gastrointestinal carcinomas and usually can readily be differentiated from carcinomas based on the morphology of the neoplastic cells that are typically spindled (70%), pure epithelioid, or mixed type. GISTs in general lack expression of cytokeratin and exhibit immunoreactivity toward CD117, CD34, or DOG1. GISTs can demonstrate a pure epithelioid morphology that can appear similar histologically to a carcinoma. Very few epithelioid GISTs have been reported to express cytokeratin, which can lead to diagnostic challenges especially in cases with pure epithelioid morphology. Epithelioid GISTs should be considered in the differential diagnosis when evaluating gastrointestinal neoplasms with overlapping epithelioid and carcinoma-like morphology. An accurate diagnosis can be made using additional immunohistochemical studies directed against CD117, CD34, or DOG1. Advanced investigations such as mutation analysis of KIT using molecular pathology methods can further assist in confirming the diagnosis.

Metastatic ductal carcinoma of the breast to colonic mucosa.

Breast cancer is the most common malignancy among women, while invasive ductal carcinoma is the most common type of invasive breast cancer. Metastatic spread to the colon and rectum in breast cancer is rare. This report describes a case of a 69-year-old woman with metastatic ductal breast cancer to the rectosigmoid, presenting as an incidental finding on screening colonoscopy. The breast carcinoma was first diagnosed 2 years prior. Colonic biopsies from colonoscopy confirmed metastatic adenocarcinoma consistent with a breast primary. Ultimately her clinical condition worsened as she developed malignant ascites, a small bowel obstruction, and new bone metastases, and the patient succumbed to her illness. Cases of metastatic breast cancer to the gastrointestinal tract have predominantly been lobular breast carcinoma. Increased awareness of colonic metastasis may lead to more accurate diagnosis and earlier systemic treatment.

Hepatic endometrial stromal sarcoma.

Endometrial stromal sarcomas are rare tumors that may recur or metastasize many years after their initial presentation. Though most recurrences are within the pelvis, distant metastases can occur, and are most common to the lungs. Metastases to the liver are extremely rare. Herein we report two cases of endometrial stromal sarcoma with metastases to the liver without a prior history of endometriosis, accompanied by their histology, immunohistochemistry, and molecular analysis in the context of a relevant literature review.

Primary pulmonary/pleural melanoma in a 13 year-old presenting as pleural effusion.

Melanoma in children, adolescents, and young adults is uncommon and reported almost exclusively as cutaneous melanoma. Melanoma presenting as a pleural effusion is very rare in adults and not reported in the pediatric population. Additionally, primary pulmonary melanoma is overall very rare and undocumented in pediatric patients. Furthermore, the distinction between a primary pulmonary/pleural melanoma versus a regressed cutaneous melanoma with pulmonary/pleural metastases remains extremely challenging. We discuss a case of a previously healthy 13-year-old girl that presented with a left-sided pleural effusion. Investigations revealed a large mediastinal mass, left-sided pleural and pulmonary nodules, a sacral mass, and bone marrow infiltration. The neoplasm was subsequently diagnosed by morphology and immunocytochemistry with histological correlation as malignant melanoma. As no mucosal, eye, or cutaneous lesions were identified, we deliberate the likelihood of a regressed cutaneous melanoma with metastases versus primary pulmonary/pleural melanoma with pleural effusion and discuss its diagnostic approach.

Gastric biomarkers: a global review.

BACKGROUND: Gastric cancer is an aggressive disease with a poor 5-year survival and large global burden of disease. The disease is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Despite the many prognostic, predictive, and therapeutic biomarkers investigated to date, gastric cancer continues to be detected at an advanced stage with resultant poor clinical outcomes. MAIN BODY: This is a global review of gastric biomarkers with an emphasis on HER2, E-cadherin, fibroblast growth factor receptor, mammalian target of rapamycin, and hepatocyte growth factor receptor as well as sections on microRNAs, long noncoding RNAs, matrix metalloproteinases, PD-L1, TP53, and microsatellite instability. CONCLUSION: A deeper understanding of the pathogenesis and biological features of gastric cancer, including the identification and characterization of diagnostic, prognostic, predictive, and therapeutic biomarkers, hopefully will provide improved clinical outcomes.

Cytomegalovirus Colitis: An Uncommon Mimicker of Common Colitides.

Cytomegalovirus latency, though ubiquitous in the human population, is known to cause colitis in both immunocompromised and immunocompetent hosts. Furthermore, the clinical, endoscopic, and histologic appearance of cytomegalovirus colitis can mimic that of inflammatory bowel disease, an extremely well-documented disease. In this context, though many reports have looked at inflammatory bowel disease with superimposed cytomegalovirus infection, less attention has been paid to cytomegalovirus as a primary cause of isolated colitis. Owing to the rarity of this phenomenon, it is important to consider this diagnosis and implement proper testing to avoid misdiagnosis and mismanagement.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH)--An uncommon precursor of a common cancer?

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare, likely under recognized entity. We report on six cases of DIPNECH that were seen in Saskatoon, SK. The cases largely have the characteristics of the typical patient profile thus far described in the literature, consistent with the limited information reported to date. Furthermore, one case had co-existing squamous cell carcinoma, which has not been previously described, and one case had concomitant adenocarcinoma. In this context, we explore the hypothesis of whether DIPNECH could play a role as an uncommon precursor in pulmonary tumorigenesis. We also propose improved diagnostic criteria for DIPNECH, which are currently ill-defined.

Autoimmune-Like Hepatitis: A "Hepatitic" Manifestation of Chronic Graft Versus Host Disease in Post-Stem Cell Transplant.

A 59-year-old female received a matched related donor stem cell transplant for chronic myelogenous leukemia. After being successfully treated with prednisone for chronic graft versus host disease that initially started 50 days posttransplant, she developed hepatic dysfunction during the steroid taper on day 531, as evidenced by jaundice, elevated liver enzymes, and increased bilirubin. Liver biopsy showed histology suggestive of autoimmune-like hepatitis, which is a rare manifestation of chronic "hepatitic" graft versus host disease.

A rare cause of heart failure with preserved ejection fraction: primary pericardial mesothelioma masquerading as pericardial constriction.

We present a case of a 30-year-old woman with a history of HIV and hepatitis C who sought medical attention because of severe oedema of the lower limbs and abdomen. CT of the chest showed a thickened pericardium, and cardiac catheterisation demonstrated constrictive physiology. She underwent pericardiectomy, but the procedure was unsuccessful because the pericardium was densely adherent to the myocardium. After consultation with several pathologists, she was diagnosed with primary pericardial mesothelioma (PPM), an exceedingly rare cardiac tumour with a fatal prognosis. She died within 3 months of presentation. The details of the case as well as pertinent literature are reviewed.

Medical error, disclosure and patient safety: a global view of quality care.

Medical errors are a prominent issue in health care. Numerous studies point at the high prevalence of adverse events, many of which are preventable. Although there is a range of severity in errors, they all cause harm, to the patient, to the system, or both. While errors have many causes, including human interactions and system inadequacies, the focus on individuals rather than the system has led to an unsuitable culture for improving patient safety. Important areas of focus are diagnostic procedures and clinical laboratories because their results play a major role in guiding clinical decisions in patient management. Proper disclosure of medical errors and adverse events is also a key area for improvement. Globally, system improvements are beginning to take place, however, in Canada, policies on disclosure, error reporting and protection for physicians remain non-uniform. Achieving a national standard with mandatory reporting, in addition to a non-punitive system is recommended to move forward.