ABSTRACT
Background and Objectives: Salivary gland tumors (SGTs) are serious challenges to pathologists. Herein, we aimed to assess epidemiological and histopathological characteristics of SGTs among Sudanese patients. Materials and Methods: This retrospective descriptive study was undertaken at The pathology department in Khartoum State between 2008 and 2018. Patient records, histopathological reports, and slides were retrieved; and re-examined by two histopathologists. Diagnoses were reclassified according to the 2017 WHO classification of SGTs. Results: Overall, 150 cases of Sudanese patients with SGT were included (90 [60%] males and 60 [40%] females). Among these, 105 were benign (70%) and 45 were malignant (30%). The parotid glands were the most common site for both benign and malignant tumors (77/150; 51%: 59 benign (76.6%) and 18 malignant [23.4%]). The next common site was the submandibular gland (54 [36%]: 38 benign [70.3%] and 16 malignant [29.7%]), followed by minor salivary glands (19 [12.7%]: 8 benign and 11 malignant [57.9%]). Benign gland entities included pleomorphic adenoma (88/105; 83.7%), oncocytoma (5/105; 4.8%), myoepithelioma (4/105; 3.8%), Whartin tumors (3/105; 2.9%), basal cell adenoma (3/105; 2.9%), and sialolipoma (2/105; 1.9%). Malignant gland entities included adenoid cystic carcinoma (12; 26.7%), mucoepidermoid carcinoma (10; 22,2%), acinic cell carcinoma (6; 13.3%), poorly differentiated carcinoma (4; 8.9%), adenocarcinoma NOS (not otherwise specified) (4; 8.9%), basal cell adenocarcinoma (3; 6.7%), carcinoma ex pleomorphic adenoma (3; 6.7%), polymorphous adenocarcinoma (2; 4.4%), salivary duct carcinoma (1; 2.2%), and epithelial-myoepithelial carcinoma (2.2%). Conclusions: SGTs shared several epidemiological and histopathological features, exhibiting high incidence in the parotid and submandibular glands, lower prevalence in minor glands, and greater male predominance.
ABSTRACT
BACKGROUND: Despite the rapidly expanding data on clinical, epidemiological and radiological aspects of coronavirus disease 2019 (COVID-19), little is known about the disease's pathological aspects. The scarcity of pathological data on COVID-19 can be explained by the limited autopsy procedures performed on deceased patients. AIM: This work aims to review and summarize the pulmonary pathological findings observed in COIVD-19 deceased individuals based on recent case series reports published in English up to September 2020. METHODS: A search in Google Scholar, PubMedÒ, MEDLINEÒ, and Scopus was performed using the keywords "autopsy and COVID-19," "postmortem and COVID-19," and "pulmonary/lung pathology and COVID-19." RESULTS: Pulmonary autopsy hallmark findings of COVID-19 cases demonstrate the presence of diffuse alveolar damage. The presence of pulmonary thrombi was reported in the majority of patients. Cellular alterations included type 2 pneumocyte hyperplasia, inflammatory cell infiltrates predominantly by lymphocytes, other mononuclear cells, and neutrophils as evident by their specific immunohistochemical markers. Electron microscopy confirmed the presence of virus particles in different cell types, including types 1 and 2 pneumocytes. CONCLUSION: The few emerging autopsy reports have substantially contributed towards our understanding of COVID-19 pulmonary histopathological aspects. COVID-19 caused acute severe respiratory manifestations that are the leading cause of morbidity and mortality in infected patients. More studies and research are needed to understand the inflammatory processes and histopathological changes associated with COVID-19 in African populations. RELEVANCE FOR PATIENTS: Postmortem investigations advance important mechanistic knowledge on COVID-19 pathophysiology and clinical outcomes and could facilitate provisions for targeted therapies.
ABSTRACT
Oral administration of a protein without adjuvant brings about oral tolerance (systemic hyporesponsiveness) to that protein by mechanisms such as antigen-induced apoptosis. We monitored the number and apoptosis induction of CD4+ T cells in antigen-specific T cell receptor transgenic mice fed the antigen ovalbumin to identify where events leading to oral tolerance occurred. The antigen was distributed throughout the body, causing apoptosis and a decrease in cell number of CD4+ T cells in most of the lymphoid system: the spleen, peripheral lymph nodes, and the thymus which was not previously reported to be affected. Although apoptosis was induced in the Peyer's patches, the cell number did not change. Unexpectedly, T cells in the mesenteric lymph nodes did not undergo apoptosis; instead, they were more numerous as compared to that in the case of control animals not administered the antigen. The results suggested that the orally administered antigen activated the intestinal immune system, while it induced immune tolerance in other sites.
