Enteroblastic adenocarcinoma of the ampulla of Vater.

Adenocarcinoma with enteroblastic differentiation is a rare histologic subtype of adenocarcinoma of the gastrointestinal tract that shows unique histologic and immunohistochemical features that resemble fetal intestinal epithelium. This histological subtype has been widely described in the stomach, where it most frequently appears, but, in other locations, it is misdiagnosed because of the poor experience in routine diagnostic setting. Here we present a case of an 87-year-old male with an adenocarcinoma of the ampulla of Vater with enteroblastic differentiation with a literature review of the cases described of this subtype in this location to date. The anatomical peculiarity of the ampulla, joined with the infrequent nature of this histological subtype, makes this case of great interest to aid to better characterize the biological behavior of these tumors.

Progression to lung fibrosis in severe COVID-19 patients: A morphological and transcriptomic study in postmortem samples.

The development of lung fibrosis is a major concern in patients recovered from severe COVID-19 pneumonia. This study aimed to document the evolution of diffuse alveolar damage (DAD) to the fibrosing pattern and define the transcriptional programs involved. Morphological, immunohistochemical and transcriptional analysis were performed in lung samples obtained from autopsy of 33 severe COVID-19 patients (median illness duration: 36 days). Normal lung and idiopathic pulmonary fibrosis (IPF) were used for comparison. Twenty-seven patients with DAD and disease evolution of more than 2 weeks had fibrosis. Pathways and genes related with collagen biosynthesis and extracellular matrix (ECM) biosynthesis and degradation, myofibroblastic differentiation and epithelial to mesenchymal transition (EMT) were overexpressed in COVID-19. This pattern had similarities with that observed in IPF. By immunohistochemistry, pathological fibroblasts (pFBs), with CTHRC1 and SPARC expression, increased in areas of proliferative DAD and decreased in areas of mature fibrosis. Immunohistochemical analysis demonstrated constitutive expression of cadherin-11 in normal epithelial cells and a similar pattern of cadherin and catenin expression in epithelial cells from both normal and COVID-19 samples. Transcriptomic analysis revealed downregulation of the Hippo pathway, concordant with the observation of YAP overexpression in hyperplastic alveolar epithelial cells. Progression to fibrosis in severe COVID-19 is associated with overexpression of fibrogenic pathways and increased in CTHRC1- and SPARC-positive pFBs. Whereas the Hippo pathway seemed to be implicated in the response to epithelial cell damage, EMT was not a major process implicated in COVID-19 mediated lung fibrosis.

Pleomorphic lobular carcinoma of the breast with osteoclast-like giant cells: a case report and review of the literature.

BACKGROUND: Breast carcinoma with osteoclast-like giant cells (OGCs) is infrequent, being most reported cased described as ductal invasive carcinomas. Invasive pleomorphic lobular carcinoma (PLC) is a distinct morphological variant of invasive lobular carcinoma characterized by higher nuclear atypia and pleomorphism than the classical type. In the best of our knowledge, a PLC with OGCs has not been previously reported. CASE PRESENTATION: We report the case of a 72-year-old woman presenting with a pleomorphic tumor of the left breast with a dense infiltration by OGCs and T lymphocytes with a 10:1 predominance of CD8+ over CD4+ cells. The diagnosis of a lymphoid or mesenchymal neoplasia was excluded after demonstrating keratin expression by the neoplastic cells. The absence of E-cadherin expression and the morphological features were consistent with the diagnosis PLC with OGCs. In addition, we demonstrated the deleterious mutation C.del866C in CDH1gene, but no mutations in any of the other 33 genes analyzed by next generation sequencing. CONCLUSIONS: Breast carcinoma with stromal osteoclast-like giant cells is a very rare tumor, for that reason, the use of the cytologic features and growth patterns in combination with immunohistochemically studies is mandatory for a correct diagnosis of lobular carcinoma. In addition, further studies are necessary to clarify the influence of OGCs in the prognosis of these patients.