Typical CT findings of COVID-19 pneumonia in patients presenting with repetitive negative RT-PCR.

Multiple polymerase chain reaction (RT-PCR) is considered the gold standard diagnostic investigation for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). However, false negative multiple polymerase chain reaction (RT-PCR) results can be diagnostically challenging. We report three patients with history of fever and different clinical signs. During the height of the pandemic in Italy (March to May 2020), these patients underwent chest computed tomography (CT) scans that showed lung alterations typical of COVID-19 with multiple negative RT-PCR tests and positive serology for SARS-CoV-2. Two of the three patients showed residual pneumonia on CT after the onset of the first clinical signs. One patient presented with diarrhoea without respiratory symptoms. These cases suggest that in the COVID-19 pandemic period, to provide an earlier specific treatment in patients with positive serology, a chest CT scan can be useful in those presenting with a fever or a history of fever associated with persistent mild respiratory symptoms or with abdominal complaints despite repeated negative RT-PCR results.

[Laparoscopic cholecystectomy in situs viscerum inversus totalis: technical note]. / Colecistectomia laparoscopica in situs viscerum inversus totalis: nota di tecnica.

The Authors report the case of a patient admitted in Emergency Room for biliary colic. She knew her dextrocardia. ECG and chest X-ray confirmed the dextrocardia. Ultrasonography and CT scan discovered a situs viscerum inversus totalis and cholecystolithiasis responsible of the abdominal colic. Laparoscopic cholecystectomy was performed. The Authors discuss the clinical case and the particular technique used.

Ten-minute silver stain for Pneumocystis carinii and fungi in tissue sections.

A ten-minute methenamine silver staining procedure for the rapid demonstration of Pneumocystis carinii and fungi in tissue sections has been developed. The procedure is optimal for both urgent and routine histologic diagnosis of diffuse, progressive, and life-threatening pulmonary infiltrates, especially in the compromised host, and of fungal lesions in general. Moreover, it is simple and brief, is applicable to both paraffined and frozen sections, and can easily be used by the pathology resident or pathologist if the need arises. It consistently yields results that are far superior to those obtained by Grocott's original methenamine silver method, and as good as or superior to those of modified silver methods and such nonsilver procedures as Giemsa's, Gram-Weigert, and toluidine blue stains.

Improved iron-hematoxylin stain for elastic fibers.

A modification of Verhoeff's elastic tissue stain with connective tissue counterstaining is described. The modified procedure requires no differentiation of the elastic fibers, thus eliminating the problem of over- or understaining of elastic fibers. The procedure is easy to perform and yields consistently good results with sharply defined elastic fibers that are easily distinguishable from other connective tissue elements. It is recommended for routine use, particularly when photomicrography is desired.

Combined alizarin red-reticulum stain for tissue localization of calcium deposits.

A method combining alizarin red and a modified silver stain for reticulum fibers in tissue sections is described. The method allows precise localization of calcium deposits and crystals in relation to epithelial and interstitial connective tissue elements. The deposits and their spatial relationships are clearly discernible by light microscopy, especially with polarization. The method is particularly useful for investigating calculogenesis and may prove to be of value in the study of the mechanism and evolution of pathologic calcification in various organs.