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. Our group presents the latest Mexican recommendations for HER2 status evaluation in breast cancer, considering the ASCO/CAP guidelines and introducing the HER2-low concept. In the era of personalized medicine, accurate HER2 status assessment remains one of the most important biomarkers in breast cancer, and the commitment of Mexican pathologists to theragnostic biomarker quality is crucial for providing the most efficient care in oncology.

[Barrett's esophagus: histochemical difference between goblet cells and blue cells]. / Esófago de Barrett: diferencia histoquímica entre células caliciformes y células azules.

Background: Barrett's esophagus (BE) is the replacement of the usual esophageal mucosa by a simple columnar epithelium with the presence of goblet cells (GC) of intestinal type. It has been related to different risk factors such as gastroesophageal reflux disease (GERD), inappropriate consumption of irritating foods, smoking and overweight. There are CC mimic cells, known as blue cells (BC), which make the diagnosis of BE difficult, due to the lack of a precise definition of the nature and location of the gastroesophageal junction and the microscopic variations in this area. Objective: To identify morphologically and with histochemical techniques Alcian blue (AA) and periodic acid-Schiff (PAS) between GC and BC. Material and methods: Retrolective cross-sectional analytical study where 45 samples of patients diagnosed with BE were included. Results: The morphological characteristics are similar in both cell varieties. PAS staining was 100%, unlike AA staining, with only 16 cases with staining, corresponding to 35.55%. Conclusions: PAS staining has a high sensitivity and specificity for the identification of GC, this being a fundamental pillar for the correct diagnosis of BE. The presence of BC detected by AA does not exclude the diagnosis of BE, since both cell types can coexist.

Introducción: el esófago de Barrett (EB) es el recambio de la mucosa habitual esofágica por un epitelio cilíndrico simple con presencia de células caliciformes (CC) de tipo intestinal. Se ha relacionado con factores de riesgo como la enfermedad por reflujo gastroesofágico (ERGE), consumo inapropiado de alimentos irritantes, tabaquismo o sobrepeso. Hay células imitadoras de las CC, las células azules (CA), que dificultan el diagnóstico del EB y es debido a falta de una definición precisa sobre la naturaleza y ubicación de la unión gastroesofágica y las variaciones microscópicas en esta zona. Objetivo: identificar morfológicamente y con las técnicas de histoquímica azul alciano (AA) y ácido peryódico de Schiff (PAS) las CC y las CA. Material y métodos: estudio transversal retrolectivo analítico; se incluyeron 45 muestras de pacientes diagnosticados con EB. Resultados: las características morfológicas son similares en ambas variedades celulares. La tinción de PAS fue del 100%, a diferencia de la tinción de AA, con solo 16 casos con tinción, correspondiente al 35.55%. Conclusiones: la tinción de PAS tiene una alta sensibilidad y especificidad para la identificación de CC, lo cual es fundamental para el correcto diagnóstico de la EB. La presencia de CA detectadas mediante AA no excluye el diagnóstico de EB, ya que ambos tipos celulares pueden coexistir.

Myxoid Endometriosis: An Entity That Can Cause Confusion with Malignant Entities.

Myxoid endometriosis, a rare entity, is part of the histological changes that can occur in endometriosis. Pathologists must know the histological guidelines for the morphological recognition of this entity, as well as the histochemical and immunohistochemical techniques that support diagnosis, and define the morphological characteristics of myxoid endometriosis. In the present work, we propose diagnostic guidelines and primary differential diagnoses using special histochemical techniques and immunohistochemical reactions to recognize this entity.

Hemangioendotelioma epitelioide cutáneo extenso multifocal agresivo. Informe de un caso / Aggressive multifocal extensive cutaneous epithelioid haemagioendothelioma. A case report

El hemangioendotelioma epitelioide es un tumor vascular infrecuente, descrito por primera vez en 1975 por Dail y Liebow como un carcinoma bronquioloalveolar. Habitualmente, se comporta como una neoplasia de bajo grado; sin embargo, se han descrito casos en los que el tumor manifiesta una elevada agresividad, extendiéndose con rapidez por todo el organismo. Presentamos el caso de un hombre de 41 años con dermatosis en muslo izquierdo y extensión rápida a abdomen, cuyo diagnóstico inicial fue de un carcinoma metastásico vs. linfoma. En la revisión de laminillas, se confirmó el diagnóstico de hemangioendotelioma epitelioide de piel, iniciando tratamiento con radioterapia. Este tumor afecta excepcionalmente la piel, habiéndose descrito pocos casos en la literatura médica.(AU)

Epithelioid haemangioendothelioma is a rare vascular tumor, first described in 1975 by Dail and Liebow as a bronchioloalveolar carcinoma. Although it usually behaves like a low-grade neoplasm, cases have been reported in which the tumor shows a high grade of malignancy, spreading rapidly throughout the body. We present the case of a 41-year-old man with dermatosis in the left thigh with rapid extension to the abdomen; the initial differential diagnoses were metastatic carcinoma versus lymphoma. When the histopathology was re-examined, a diagnosis of skin epithelioid hemangioendothelioma was confirmed and treatment with radiotherapy was initiated. This tumour rarely affects the skin; there are only a few previously reported cases.(AU)

[Aggressive multifocal extensive cutaneous epithelioid haemagioendothelioma. A case report]. / Hemangioendotelioma epitelioide cutáneo extenso multifocal agresivo. Informe de un caso.

Epithelioid haemangioendothelioma is a rare vascular tumor, first described in 1975 by Dail and Liebow as a bronchioloalveolar carcinoma. Although it usually behaves like a low-grade neoplasm, cases have been reported in which the tumor shows a high grade of malignancy, spreading rapidly throughout the body. We present the case of a 41-year-old man with dermatosis in the left thigh with rapid extension to the abdomen; the initial differential diagnoses were metastatic carcinoma versus lymphoma. When the histopathology was re-examined, a diagnosis of skin epithelioid hemangioendothelioma was confirmed and treatment with radiotherapy was initiated. This tumour rarely affects the skin; there are only a few previously reported cases.

Case Report: Uterine Adenosarcoma With Sarcomatous Overgrowth and Malignant Heterologous Elements.

A 46- year-old woman presented a uterine adenosarcoma originating in the lower uterine segment. The diagnosis was made in an endometrial biopsy and confirmed in the pathological examination of the complete surgical specimen, both identifying heterologous malignant elements. In addition, complementary immunohistochemical studies were performed. We reviewed the literature, illustrating the clinical and morphological characteristics and the differential diagnoses to be evaluated.

Monofrequency electrical impedance mammography (EIM) diagnostic system in breast cancer screening.

BACKGROUND: Some evidence has shown that malignant breast tumours have lower electrical impedance than surrounding normal tissues. Electrical impedance could be used as an indicator for breast cancer detection. The purpose of our study was to analyse the sensitivity and specificity of electrical impedance mammography (EIM) and its implementation for the differential diagnosis of pathological lesions of the breast, either alone or in combination with mammography/ultrasound, in 1200 women between 25 and 70 years old. METHODS: This study is a prospective, cross-sectional epidemiological observational study of serial screening. The women were invited to participate and signed a consent letter. Impedance imaging of the mammary gland was evaluated with the computerized mammography equipment of MEIK electroimpedance v.5.6. (0.5 mA, 50 kHz), developed and manufactured by PKF SIM-Technika®. The successful identification of breast cancer along with the sensitivity, specificity, and positive and negative predictive values of EIM were determined as follows: % sensitivity; % specificity; % positive predictive value (PPV); and % negative predictive value (NPV). RESULTS: EIM had a sensitivity of 85% and a specificity of 96%; the positive predictive value was 12%, and the negative predictive value was 99%. Seven cases were biopsy confirmed cancers. Significant correlations between the electrical conductivity index and body mass index (BMI) (p = 0.04) and patient age were observed (p = 0.01). We also observed that the average conductivity distribution increased according to age group (p = 0.001). We used the chi-squared test to assess the interactions between percent density and BMI (normal < 25 kg/m2 (n = 310), overweight 25-29.9 kg/m2 (n = 418) and obese ≥30 (n = 437)) (p <  0.05). The patients with a diagnosis of mammary carcinoma had a BMI of 35.51 kg/m2. CONCLUSIONS: Our results demonstrate that the use of monofrequency electrical impedance mammography (EIM) in the detection of breast cancer had a sensitivity and specificity of 85 and 96%, respectively. These findings may support future research in the early detection of breast cancer. EIM is a non-radiation method that may also be used as a screening method for young women with dense breasts and a high risk of developing breast cancer.

Effect of varying the crosslinking degree of a pericardial implant with oligourethane on the repair of a rat full-thickness abdominal wall defect.

The stability and bioactivity of biologic implants rely mainly on the control of the crosslinking process of collagen. However, the most common methods have no control on the crosslinking degree producing it excessively. This study outlines the role of crosslinking of collagen-based implants with oligourethane on the host response following reconstruction of a rat full-thickness abdominal wall defect. We decellularized and crosslinked bovine pericardial tissue to achieve two crosslinking degrees. For the decellularized implants, named as non-crosslinked (N-CL), the collagen-amines were 0.42 ± 0.02 mmol/mg. Crosslinking by the oligourethane reduced the primary amine concentration to 0.28 ± 0.01 and 0.19 ± 0.01 mmol/mg; these values were classified as low (∼30%, L-CL) and medium crosslinking (∼50%, M-CL), respectively. By imaging the implants using second harmonic generation microscopy, we observed undulated bundles of collagen fibers organized in multi-directed layers localized in N-CL and L-CL samples. Post-implantation, a negligible change in the organization of collagen fibers in the crosslinked implants was observed, suggesting that the in vivo biodegradation was delayed. An enlargement of the implant area was also observed, without rupture, in all three (N-CL, L-CL, M-CL) materials, whereas adhesion to the omentum, but not to the bowel, was observed. The number of blood vessels after 90-day implantation in N-CL and L-CL was 13 ± 1 and 12 ± 1 per field, respectively, while the number significantly decreased to 2 ± 1 in M-CL. The results suggest that the controlled degree of crosslinking in oligourethane-modified biologic implants can be used as a strategy to balance biodegradation and remodeling in surgical repair of soft tissues.

Multiple hereditary osteochondromatosis with spinal cord compression: case report.

OBJECTIVE: The purpose of the report is to describe a patient with hereditary osteochondromatosis and spinal cord compression at the thoracic level. CLINICAL FEATURES: An 8-year-old patient with hereditary osteochondromatosis inherited from his father presented paraparesis in the left foot, leading to complete paralysis in both legs. INTERVENTION: In a CT scan, a bony tumor rising from the posterior wall of the T3 body narrowing the spinal canal, and the MRI spinal cord compression at the same level and the hydrosyringomyelic cavity extended to the conus medullaris; with an anterior thoracic approach to T2-T4, the fibro-cartilaginous tumor was removed, and the stabilization was completed with bone graft and a plate. Two months after surgery, the patient recovered strength in both legs. CONCLUSIONS: A detailed family history through examination-guided advanced imaging and biopsy provides useful information for diagnosis and appropriate management of occupative lesions in patients affected with multiple hereditary exostosis.

The component leaching from decellularized pericardial bioscaffolds and its implication in the macrophage response.

The extracellular matrix molecules remaining in bioscaffolds derived from decellularized xenogeneic tissues appear to be important for inducing cell functions conducting tissue regeneration. Here, we studied whether decellularization methods, that is, detergent Triton X-100 (TX) alone and TX combined with reversible alkaline swelling (STX), applied to bovine pericardial tissue, could affect the bioscaffold components. The in vitro macrophage response, subdermal biodegradation, and cell infiltration were also studied. The results indicate a lower leaching of fibronectin, but a higher leaching of laminin and sulfated glycosaminoglycans from tissues decellularized with STX and TX, respectively. The in vitro secretion of interleukin-6 and monocyte chemoattractant protein by RAW264.7 macrophages is promoted by decellularized bioscaffold leachates. A lower polymorphonuclear cell density is observed around decellularized bioscaffolds at 1-day implantation; concurrently showing a higher cell infiltration in STX- than in TX-implant. Cells infiltrated into TX-implant show a fibroblastic morphology at 7-day implantation, concurrently the capillary formation is observed at 14-day. Pericardial bioscaffolds suffer biodegradation more pronounced in STX- than in TX-implant. Both TX and STX decellularization methods favor a high leaching of basal lamina components, which presumably promotes a faster macrophage stimulation compared to nondecellularized tissue, and appear to be associated with an increased host cell infiltration in a rat subdermal implantation. Meanwhile, the connective tissue components leaching from TX decellularized bioscaffolds, unlike the STX ones, appear to be associated with an enhanced angiogenesis accompanied by an early-promoted fibroblastic cell transition. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2810-2822, 2016.

Timoma pleural primario con presentación clínica de mesotelioma maligno / Primary pleural thymoma presenting as a malignant mesothelioma. A case report

Los timomas ectópicos rara vez se presentan como tumores pleurales. Informamos el caso de un timoma ectópico que se manifiesta clínica y radiológicamente como mesotelioma maligno en una mujer de 46 años quien presentó dolor torácico, disnea y pérdida de peso. Se realizó resección del tumor con diagnóstico patológico definitivo de timoma pleural ectópico B2 de acuerdo con la OMS y Masaoka estadio IVa. No se observó continuidad con el tejido del timo normal, por lo que pensamos que el timoma se originó de tejido ectópico en pleura (AU)

Ectopic thymoma is rarely found in the pleura. We report a case of a 46 year old female who presented with chest pain, shortness of breath and weight loss and with the clinical and radiological signs of a malignant mesothelioma. After surgical resection, the tumour was diagnosed as a pleural thymoma WHO type B2 and Masaoka stage IVa. As there was no continuity with the normal thymus tissue, the thymoma was thought to have arisen from ectopic thymic tissue in the pleura (AU)

Linfoma primario del apéndice cecal con presentación clínica de apendicitis aguda / Primary lymphoma of the appendix presenting as acute appendicitis

Los linfomas primarios de apéndice son neoplasias malignas poco frecuentes que, cuando aparecen, pueden presentarse como un cuadro de apendicitis aguda. El estudio histopatológico y de inmunohistoquímica es obligatorio para realizar el diagnóstico, y es necesario descartar su origen en otro sitio del cuerpo. Informamos el caso de un linfoma no Hodgkin primario de apéndice, con sus hallazgos clínicos, histopatológicos y de inmunohistoquímica, en una mujer de 36 años(AU)

Primary lymphomas of the appendix are rare malignancies that may present as acute appendicitis. Histopathology and immunohistochemistry are indispensable in order to exclude an origin elsewhere. We describe the clinical, histopathological and immunohistochemical characteristics of a case of primary appendix lymphoma in a 36 year old female(AU)

Carcinoma de mama con células gigantes tipo osteoclasto. Informe de un caso de una variante rara / A rare variant of breast cancer with osteoclast-like giant cells. A case report

El carcinoma de mama con células gigantes tipo osteoclasto (CMCGO) es una variante distintiva y rara del carcinoma de mama, y se han reportado casos con patrones de crecimiento en casi todas los tipos de carcinoma mamario, siendo rara la presentación en los tumores bien diferenciados. Informamos un caso de carcinoma ductal infiltrante bien diferenciado con abundantes células gigantes tipo osteoclasto (CGO). Se realizaron reacciones de inmunohistoquímica para demostrar la diferencia inmunofenotípica de la neoplasia y de las CGO. Se hace una revisión de la literatura, ilustrando las características morfológicas, y se discuten los diagnósticos diferenciales(AU)

Breast carcinoma with osteoclast-like giant cells (BCOGC) is a rare, distinctive form of breast cancer. Although cases have been reported with many growth patterns in almost all types of breast cancer, being rarely found in well differentiated tumours. We report a case of well-differentiated ductal carcinoma with abundant osteoclast-like giant cells (OGC). Immunohistochemistry demonstrated the immunophenotypic differences of the tumour and the OGC. The literature is reviewed, illustrating the characteristic morphology and the differential diagnosis is discussed(AU)

Seudotumor hemofílico: complicación poco frecuente en pacientes con deficiencia del factor VIII y IX que asemeja sarcoma de partes blandas / Haemophilic pseudotumour: a rare complication of factor VIII and IX deficiency which can mimic soft tissue sarcoma. A case report and review of the literature

El seudotumor hemofílico es una complicación infrecuente en pacientes hemofílicos y es básicamente un hematoma encapsulado en diferentes estadios de organización, que muchas veces llega a confundirse clínica y radiográficamente como un sarcoma osteogénico o de tejidos blandos. Informamos el caso de un varón de 30 años con hemofilia A y diagnóstico de seudotumor hemofílico en miembro pélvico izquierdo con evolución de un año. Se realizó amputación supracondílea en su manejo multidisciplinario, así como un estudio inmunohistoquímico. Se revisó la literatura(AU)

A rare complication of haemophilia is haemophilic pseudotumour which is an encapsulated haematoma in different stages of organization. However, it often resembling osteogenic or soft tissue sarcoma, both clinically and radiologically. We report a case of a 30 year old male with haemophilia A and a one year history of haemophilic pseudotumour of the left leg. A multidisciplinary team was responsible for his management. A supracondylar amputation was performed and immunohistochemical studies were carried out. The literature was reviewed(AU)

Angiofibroma atípico de la amígdala palatina / Atypical angiofibroma of the palatine tonsil. A case report

Los angiofibromas extranasales son tumores benignos poco frecuentes que tienen características clínicas e histológicas diferentes a su contraparte nasal. Informamos un caso de angiofibroma atípico de la amígdala palatina, con sus hallazgos histopatológicos e inmunohistoquímicos, en un hombre de 60 años(AU)

Extranasal angiofibromas are rare benign tumours with different clinical and histological characteristics from their nasal counterparts. We describe a case of atypical angiofibroma of the palatine tonsil in a 60 years old man and discuss its characteristic histopathology and immunohistochemistry(AU)

Rotura uterina espontánea y hemoperitoneo como primera manifestación de tumor mixto mülleriano maligno. Informe de un caso de autopsia y revisión de la literatura / Spontaneous rupture of the uterus and hemoperitoneum secondary to a mixed müllerian tumour. A case report and review of the literature

Se presenta el caso de una mujer de 75 años de edad con malestar general y anemia progresiva de origen desconocido, que falleció por choque hipovolémico. Se realizó estudio de autopsia, donde se encontró rotura uterina y hemoperitoneo, a expensas de una neoplasia uterina maligna. En el estudio histopatológico se evidenció un tumor mixto mülleriano maligno heterólogo. Se realiza una revisión de la literatura acerca de la asociación de esta y otras patologías con ruptura uterina espontánea(AU)

A 75 year old female who died from hypovolemic shock after a period of progressive malaise and anaemia of unknown origin was seen on autopsy to have uterine rupture and haemoperitoneum secondary to a heterologous malignant mixed müllerian tumour. The literature on the association of spontaneous uterine rupture with this neoplasm and other conditions is reviewed(AU)

Tumor mesenquimal fosfatúrico con rosetas gigantes: causa poco frecuente de osteomalacia oncogénica / Phosphaturic mesenchymal tumour with giant rosettes: a rare cause of oncogenic osteomalacia

El tumor mesenquimal fosfatúrico es una neoplasia rara que causa osteomalacia oncogénica por la fosfatonina FGF-23. Se describe el caso de una mujer que fue diagnosticada de osteomalacia oncogénica donde la tomografía computarizada reveló un tumor de tejidos blandos en el tórax. Una vez extirpado, fue identificado como tumor mesenquimal fosfatúrico tipo tejido conectivo mixto; se hizo revisión de la literatura y sus diagnósticos diferenciales. En este caso observamos rosetas gigantes, un hallazgo histológico no descrito antes(AU)

Phosphaturic mesenchymal tumour is a rare neoplasm which causes oncogenic osteomalacia due to the phosphatonin FGF-23. We report a case of a female patient crippled with oncogenic osteomalacia who was seen to have a soft tissue tumour of the thorax. The tumour was diagnosed as a phosphaturic mesenchymal tumour (mixed connective tissue variant). Giant rosettes were seen, a finding not previously reported. The differential diagnosis is discussed and the literature reviewed(AU)

Paraganglioma paravertebral maligno con metástasis óseas, pulmonares y en el sistema nervioso central / Malignant paravertebral paraganglioma with metastases in bone, lung and central nervous system. A case report

Se describe el caso de un varón de 40 años con dolor en hemitórax izquierdo. Inicialmente la neoplasia se extirpó de forma incompleta. Cuatro meses después, el paciente fue reintervenido por recidiva local y presentó metástasis en pulmón, una costilla y el sistema nervioso central. El estudio histopatológico mostró una proliferación celular con patrón de crecimiento zellballen y positividad para cromogranina, sinaptofisina y enolasa neuronal específica. El índice de proliferación (Ki-67) fue superior al 2%. El conjunto de datos confirmó el diagnóstico de paraganglioma maligno(AU)

A 40-year old man presenting with left sided chest pain, initially underwent surgery during which a tumour was partially removed. Four months later, he had a further surgical intervention to remove a local recurrence and metastases were found in the lung, a rib and the central nervous system. The biopsy showed cell proliferation with a zellballen growth pattern and positivity for chromogranin, synaptophysin and neuron-specific enolase. The proliferation index (Ki-67) was higher than 2%. These findings confirmed the diagnosis of malignant paraganglioma(AU)

Carcinoma neuroendocrino de células grandes de la próstata. Informe de autopsia de un caso inusual / Large cell neuroendocrine carcinoma of the prostate. A case report and review of the literature

Se presenta el caso de un hombre de 69 años de edad con antecedente de adenocarcinoma de próstata, el cual falleció por tromboembolia pulmonar. Se realizó estudio de autopsia, en el que se encontró un carcinoma neuroendocrino de células grandes de la próstata, que fue confirmado por inmunohistoquímica. Se hace una revisión de la literatura, ilustrando las características morfológicas de esta rara neoplasia(AU)

A case is presented of a 69-year-old man with a previous history of adenocarcinoma of the prostate who died of pulmonary embolism. Autopsy revealed a large cell neuroendocrine carcinoma of the prostate, which was confirmed by immunohistochemistry. The morphology and differential diagnosis of this rare tumour is discussed together with a review of the literature(AU)

[Synchronic hepatocellular carcinoma with atrial myxoma. A case report]. / Carcinoma hepatocelular sincrónico con mixoma auricular. Informe de un caso.

The case of a 60-year-old woman with history of cryptogenic hepatic cirrhosis and a probable hepatic tumor, who died of upper gastrointestinal bleeding secondary to esophageal varices, is presented. An autopsy study was carried out, which showed a hepatocellular carcinoma and a left atrial cardiac myxoma with glandular elements. A review of the literature, searching for the association between these two tumors, in addition to other tumors, is presented.