Navigating HER2-Low Testing in Invasive Breast Cancer: Update Recommendations for Pathologists.

The article discusses the importance of accurately distinguishing HER2-low from HER2-negative breast cancer, as novel ADCs have demonstrated activity in a large population of patients with HER2-low-expressing BC. While current guidelines recommend a dichotomous classification of HER2 as either positive or negative, the emergence of the HER2-low concept calls for standardization of HER2 testing in breast cancer, using currently available assays to better discriminate HER2 levels. This review covers the evolution and latest updates of the ASCO/CAP guidelines relevant to this important biomarker in breast cancer, including still-evolving concepts such as HER2 low, HER2 heterogeneity, and HER2 evolution.

Anaplastic large cell lymphoma with ALK::ATIC fusion mimicking a histiocytic sarcoma debuting as an anterior thoracic soft tissue tumor with exceptional clinicopathological, morphological and molecular features.

A 56-year-old woman debuted with a palpable painless mass in the anterior thorax wall at the level of the second and third right parasternal intercostal space, which progressively increased in size over 5 months accompanied by localized skin rash, mild dyspnea and chest pain when changing position. Imaging studies showed a soft tissue mass measuring 75 × 62 mm and a density of 34 Hounsfield Units that had caused the lysis of the costal arches and grew expansively towards the anterior mediastinum, without identifying mediastinal adenopathies only by this imaging method. Core biopsy was performed, which was initially diagnosed as histiocytic sarcoma (HS); however, when the diagnostic panel was expanded to include molecular and NGS studies, the final diagnosis was anaplastic large cell lymphoma with ALK::ATIC fusion.

[Large cell carcinoma of the lung with null immunophenotype: Case report & brief review].

Large cell carcinoma of the lung with null-immunophenotype (LCC-NI) is a diagnostic entity that is especially uncommon now as it does not have any type of cell differentiation or its own molecular alterations. It presents an exceptional diagnostic challenge; indeed, the diagnosis is only possible with complete surgical excision and adequate immunohistochemical and molecular studies. We report the case of a 69-year-old male, with a history of long-term smoking who presented with pleuritic pain.

Intestinal-type adenocarcinoma arising from a villous adenoma in the renal pelvis in the context of a kidney abscess: Case report.

Villous adenoma is a benign neoplasm with an exceptional presentation in the renal pelvis, hence very few cases have been reported. Herein we present the case of a patient who presented with left flank pain clinically suggestive of complicated pyelonephritis, culminating in simple nephrectomy with a villous adenoma in the renal pelvis as histopathological finding associated to the presence of a microscopic focus of intestinal-type adenocarcinoma.

Selective efficacy and safety of first line and non front line antineoplasic agent combinations determined with individualized assays on colorectal cancer primary cultures.

Purpose: To evaluate the efficacy of first-line and not-conventional antineoplastic drug combinations in colorectal adenocarcinoma primary cultures (CRAC PCs).

Methods: The efficacy and safety of 21 drug combinations (DCs) were evaluated using a simplified adenosine triphosphate-based chemotherapy response assay (sATP-CRA). The efficacy of each DC was reported as the percentage of cell death (PCD) produced on each of 12 CRAC-PCs, and the safety of each DC was evaluated as a safety window (SW).

Local secretion of stress hormones increases in alopecia areata lesions after treatment with UVA-1 phototherapy.

Alopecia areata (AA) is an autoimmune disease of the hair follicle. Keratinocytes of the hair follicle generate an immunosuppressive environment by the local secretion of hormones of the hypothalamic-pituitary-adrenal axis of the skin (skin HPA analog). Our objective was to measure the local production of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and α-melanocyte-stimulating hormone (α-MSH) in the scalp tissue of patients with AA before and after ultraviolet A1 (UVA-1) phototherapy to determine their role in the pathogenesis of AA and the effect of UVA-1 on the AA hormonal environment.

Gene expression profiling demonstrates WNT/β-catenin pathway genes alteration in Mexican patients with colorectal cancer and diabetes mellitus.

Purpose: Several studies have shown a strong association between diabetes mellitus (DM) and increased risk of colorectal cancer (CRC). The fundamental mechanisms that support this association are not entirely understood; however, it is believed that hyperinsulinemia and hyperglycemia may be involved. Some proposed mechanisms include upregulation of mitogenic signaling pathways like MAPK, PI3K, mTOR, and WNT, which are involved in cell proliferation, growth, and cancer cell survival.

Thymidylate synthase polymorphism in Mexican patients with colon cancer treated with 5-fluorouracil.

Purpose: We analyzed the genotype and allele frequency of variable number tandem repeats (VNTR)-thymidylate synthase (TS) and its relationship with the disease evolution in colon cancer patients.

Methods: We selected 24 paraffin-embedded colon cancer tissue samples from Mexican patients who received a 5-fluorouracil (5-FU)-based chemotherapy regimen. Tumor tissue was digested with proteinase K and genomic DNA was isolated by the standard method with phenol-chloroform extraction.

CDX-2, MUC-2 and B-catenin as intestinal markers in pure mucinous carcinoma of the breast.

Background: Pure mucinous adenocarcinoma of the breast is a rare entity characterized by the production of variable amounts of mucin comprising 1% to 6% of breast carcinomas. Some mucinous adenocarcinomas have shown expression of intestinal differentiation markers such as MUC-2. This study examines the expression of intestinal differentiation markers in this type of breast carcinoma.

TSPAN33 is a novel marker of activated and malignant B cells.

We have identified Tspan33 as a gene encoding a transmembrane protein exhibiting a restricted expression pattern including expression in activated B cells. TSPAN33 is a member of the tetraspanin family. TSPAN33 is not expressed in resting B cells, but is strongly induced in primary human B cells following activation.

[The imprint cytology: a tool diagnosis in the operating room].

Background: since 1929, the imprint cytology has a great value in the transoperatory as a diagnostic tool and in some cases as an alternate method.

Methods: during two years period, 416 transoperatory specimens and 384 frozen sections were performed in the Pathology and Cytopathology Department of the University Hospital, "Dr. José E.

TLE1 is expressed in the majority of primary pleuropulmonary synovial sarcomas.

Pleuropulmonary synovial sarcoma (PPSS) is a rare entity, similar to synovial sarcoma of soft tissue (STSS). There are 120 published cases of PPSS, but no studies have explored the expression of TLE1. In soft tissues, it has been proven a useful marker, but in tumors of other sites, its expression has not been explored.

[Ovarian ginandroblastoma as a transcesarean incidental finding. A case report and literature review].

The gynandroblastoma is an extremely rare sexual cord stromal tumor, which contains both male and female elements, characterized by Sertoli or Leydig cells and granulose cells. We describe an ovarian gynandroblastoma in a 28 year-old female patient, found accidentally during a cesarean section operation. There is only one reported case in world literature occurring in a pregnant woman.

Analysis of DNA mismatch repair proteins expression and BRAF V600E mutation in a subset of early- and late-onset colorectal carcinoma patients in Mexico.

Background And Aims: A third of colorectal carcinomas (CRC) affect patients <50 years of age. Fifteen percent of CRC cases with microsatellite instability are due to inherited germ-line mutations in DNA mismatch repair genes. The rest have an epigenetic hypermethylation of the MLH1 promoter in whom the BRAF V600E mutation is a common hallmark.

Diagnosis of carcinosarcoma metastatic to the umbilicus by fine needle aspiration biopsy: a case report.

Background: Metastasis to the umbilicus, known as Sister Mary Joseph's nodule, sometimes represents the first clinical manifestation of an internal malignancy. These nodules are infrequent, and their discovery has prognostic implications.

Case: An 86-year-old woman presented with an ultrasound diagnosis of peritoneal carcinomatosis and the presence of a round lesion in the umbilical area.

Prevalence of eosinophilic esophagitis in patients with refractory gastroesophageal reflux disease symptoms: A prospective study.

Background: Eosinophilic esophagitis (EoE) is not routinely considered in the differential diagnosis of refractory gastroesophageal reflux disease (GERD).

Aims: To prospectively evaluate the prevalence of EoE and describe the clinical features and predictors of EoE in patients with refractory symptoms of GERD.

Methods: Esophageal biopsies were obtained in patients with symptoms of GERD refractory to 8 weeks of conventional antisecretory therapy.

mRNA levels of TLR4 and TLR5 are independent of H pylori.

Aim: To determine if the presence H pylori or its virulence affect toll-like receptor 4 (TLR4) and TLR5 mRNA expression levels.

Methods: For the in vivo assays, gastric biopsies were obtained from 40 patients and H pylori status was determined. For the in vitro assays, human gastric adenocarcinoma mucosal cells (AGS) were cultured in the presence or absence of twelve selected H pylori strains.

[Her2-Neu expression in ductal adenocarcinomas of the breast gland: correlation with histopathological parameters and estrogen receptors' expression in Mexican patients].

Background: Breast cancer is a general health problem that annually produces 400,000 deaths worldwide. Its early diagnosis leads to high cure rates; nevertheless, in Mexico City this happens rarely. Her2-Neu is an oncogene that is expressed on breast cancer cells, with aggressive behaviour and metastasis.

Diagnostic utility of invasive tests and serology for the diagnosis of Helicobacter pylori infection in different clinical presentations.

Background: Invasive and noninvasive tests are used for the diagnosis of Helicobacter pylori infection. The aim of this study was to determine the diagnostic utility of rapid urease test (RUT), culture, histology and serology for the diagnosis of H. pylori in patients with different clinical presentations.

Fine needle aspiration biopsy diagnosis of metastatic neoplasms of the breast. A three-case report.

Metastases to the breast are unusual lesions that make up approximately 2% of all malignant mammary neoplasms and may mimic both benign and malignant primary neoplasms from a clinical point of view, as well as in imaging studies. Arriving at a correct diagnosis is therefore essential in order to establish appropriate management. We present three cases of metastatic neoplasms diagnosed through fine needle aspiration biopsy and immunocytochemistry.