Monkeypox: A Histopathological and Transmission Electron Microscopy Study.

The global outbreak of human monkeypox virus (hMPXV1) in 2022 highlighted the usefulness of dermatological manifestations for its diagnosis. Infection by the human monkeypox virus thus necessitated inclusion in the diagnostic repertoire of dermatopathology. To assess the histopathological and microscopical findings of cutaneous lesions related to hMPXV infection, we analyzed skin biopsies from patients with positive MPXV DNA polymerase chain reaction presenting with a typical course of hMPXV1 infection. The most prominent histopathological findings were ascribable to a pustular stage in which epidermal necrosis with areas of non-viable keratinocytes and a "shadow cell" appearance were evident; in some cases, the deep portion of the hair follicle and the acrosyringial epithelium were affected. The main cytopathic modifications included ballooning keratinocytes, followed by Guarnieri bodies and a ground glass appearance of the keratinocytes' nuclei, together with a dense mixed inflammatory cell infiltrate with prominent neutrophil exocytosis. Transmission electron microscopy analysis demonstrated viral particle aggregates in the cytoplasm of keratinocytes, without any involvement of the nucleus. Interestingly, we also found the presence of viral particles in infected mesenchymal cells, although to a lesser extent than in epithelial cells. Through this study, we contributed to expanding the histological and microscopic knowledge of the human mpox virus, a key step to understanding current and potential future trends of the disease, as well as of other Orthopoxvirus infections.

SARS-CoV-2 Detection by Digital Polymerase Chain Reaction and Immunohistochemistry in Skin Biopsies from 52 Patients with Different COVID-19-Associated Cutaneous Phenotypes.

BACKGROUND: COronaVIrus Disease 19 (COVID-19) is associated with a wide spectrum of skin manifestations, but SARS-CoV-2 RNA in lesional skin has been demonstrated only in few cases. OBJECTIVE: The objective of this study was to demonstrate SARS-CoV-2 presence in skin samples from patients with different COVID-19-related cutaneous phenotypes. METHODS: Demographic and clinical data from 52 patients with COVID-19-associated cutaneous manifestations were collected. Immunohistochemistry and digital PCR (dPCR) were performed in all skin samples. RNA in situ hybridization (ISH) was used to confirm the presence of SARS-CoV-2 RNA. RESULTS: Twenty out of 52 (38%) patients presented SARS-CoV-2 positivity in the skin. Among these, 10/52 (19%) patients tested positive for spike protein on immunohistochemistry, five of whom had also positive testing on dPCR. Of the latter, one tested positive both for ISH and ACE-2 on immunohistochemistry while another one tested positive for nucleocapsid protein. Twelve patients showed positivity only for nucleocapsid protein on immunohistochemistry. CONCLUSIONS: SARS-CoV-2 was detected only in 38% of patients, without any association with a specific cutaneous phenotype, suggesting that the pathophysiology of cutaneous lesions mostly depends on the activation of the immune system. The combination of spike and nucleocapsid immunohistochemistry has higher diagnostic yield than dPCR. Skin persistence of SARS-CoV-2 may depend on timing of skin lesions, viral load, and immune response.

Histological evaluation of ischemic alterations in donors after cardiac death: A useful tool to predict post-transplant renal function.

Kidneys retrieved from donors after cardiac death (DCD) pose significant challenges from a clinical and technical point of view, undergoing a variable degree of ischemia-reperfusion injury. At present, the utilization of kidneys is assessed according to the Karpinski score, which does not take into account the ischemic insult and does not predict the functional recovery of the organ once transplanted. Therefore, the correlation between biopsy results and post-transplant graft function is still debated. In this study we examined kidney biopsies from DCD donors; we calculated the Karpinski score and subsequently identified and quantified the ischemic lesions in the glomerular, interstitial, and tubular compartments. These same lesions were quantified in kidney biopsies from donors after brain death (DBD) in a case-control analysis. The collected data were correlated with the clinical data of the donors and the post-transplant follow-up. Proximal tubule alterations are crucial in ischemia-reperfusion damage, showing precise histological alterations, which are more frequent in DCD than in DBD donors and are statistically correlated with functional recovery of the organ. Quantification of ischemic tubular lesions in biopsies of kidneys from DCD donors is a useful tool for predicting post-transplant renal function and a valid parameter for assessing the quality of the graft.

Chemotherapy for breast cancer during pregnancy induces vascular alterations and impaired development of placental villi: A preliminary histopathological study.

OBJECTIVE: To evaluate histological alterations in placentas of women affected by breast cancer and treated with chemotherapy during pregnancy. STUDY DESIGN: We retrospectively reviewed histological slides of 23 placentas of patients affected by breast cancer and treated with chemotherapy during pregnancy and 23 control placentas of women without breast cancer and with physiological pregnancies of the same gestational age. RESULTS: All the patients had breast ductal infiltrating carcinoma, 19 of 23 cases had a G3 cancer. All patients were treated with 2-6 cycles of chemotherapy starting after 16 weeks of gestation, with different protocols. No hypertensive complications and no pre-eclampsia episodes were observed; birth weight was consistent with gestational age in all babies in both group with no uneventful outcomes and no perinatal mortality or fetal malformations. Twenty out of 23 cases (86 %) showed hypoxia-induced villous alterations, including increased syncytial knotting (Tenney-Parker changes), perivillar fibrin deposits, distal villous hypoplasia or accelerated maturation and focal villous chorangiosis. These alterations were found in 19 out of 23 controls (83 %), with no statistically significant difference between the two groups. CONCLUSIONS: These results shows that chemotherapy in the second and third trimester of pregnancy may lead to non-specific alterations in placental vasculature and morphology.