Digital pathology: accurate technique for quantitative assessment of histological features in metabolic-associated fatty liver disease.

BACKGROUND: Histological evaluation of metabolic-associated fatty liver disease (MAFLD) biopsies is subjective, descriptive and with interobserver variability. AIMS: To examine the relationship between different histological features (fibrosis, steatosis, inflammation and iron) measured with automated whole-slide quantitative digital pathology and corresponding semiquantitative scoring systems, and the distribution of digital pathology measurements across Fatty Liver Inhibition of Progression (FLIP) algorithm and Steatosis, Activity and Fibrosis (SAF) scoring system METHODS: We prospectively included 136 consecutive patients who underwent liver biopsy for MAFLD at three Spanish centres (January 2017-January 2020). Biopsies were scored by two blinded pathologists according to the Non-alcoholic Steatohepatitis (NASH) Clinical Research Network system for fibrosis staging, the FLIP/SAF classification for steatosis and inflammation grading and Deugnier score for iron grading. Proportionate areas of collagen, fat, inflammatory cells and iron deposits were measured with computer-assisted digital image analysis. A test-retest experiment was performed for precision repeatability evaluation. RESULTS: Digital pathology showed strong correlation with fibrosis (r = 0.79; P < 0.001), steatosis (r = 0.85; P < 0.001) and iron (r = 0.70; P < 0.001). Performance was lower when assessing the degree of inflammation (r = 0.35; P < 0.001). NASH cases had a higher proportion of collagen and fat compared to non-NASH cases (P < 0.005), whereas inflammation and iron quantification did not show significant differences between categories. Repeatability evaluation showed that all the coefficients of variation were ≤1.1% and all intraclass correlation coefficient values were ≥0.99, except those of collagen. CONCLUSION: Digital pathology allows an automated, precise, objective and quantitative assessment of MAFLD histological features. Digital analysis measurements show good concordance with pathologists´ scores.

Giant pilomatrixoma: a distinctive clinical variant: a new case and review of the literature.

Pilomatrixoma is a benign adnexal tumor very common in pediatric age and in young adults that derives from follicular matrix cells. Although clinically it usually presents as a subcutaneous nodule of bluish color less than 3cm in size, multiple clinicopathological variants have been described in the literature. Among these we can find the giant pilomatrixoma, a rare clinical variant that reaches a size greater than or equal to 4cm and can simulate the clinical presentation of a malignant neoplasm. We report a 59-year-old man with an exophytic and ulcerated nodule in the left parotid region that was removed with the suspected diagnosis of a cutaneous squamous cell carcinoma. Histopathological analysis showed a proliferation of basaloid cells with areas of transition to ghost cells, under granulation tissue, hemorrhage, and an ulcerated epidermis. Thus, the diagnosis of giant pilomatrixoma was made. We reviewed the literature and found a total of 53 articles that report a total of 71 cases of giant pilomatrixoma. It is important to recognize this clinical subtype of pilomatrixoma because, apart from the possibility of being clinically confused with malignant lesions, the clinicopathological differential diagnosis must be made with the proliferating pilomatrixoma and pilomatrixcarcinoma.

Autopsy findings from the first known death from Severe Acute Respiratory Syndrome SARS-CoV-2 in Spain.

The new coronavirus SARS-CoV-2, first identified in Wuhan, China in December, 2019, can cause Severe Acute Respiratory Syndrome (SARS) with massive alveolar damage and progressive respiratory failure. We present the relevant autopsy findings of the first patient known to have died from COVID19 pneumonia in Spain, carried out on the 14th of February, 2020, in our hospital (Hospital Arnau de Vilanova-Lliria, Valencia). Histological examination revealed typical changes of diffuse alveolar damage (DAD) in both the exudative and proliferative phase of acute lung injury. Intra-alveolar multinucleated giant cells, smudge cells and vascular thrombosis were present. The diagnosis was confirmed by reverse real-time PCR assay on a throat swab sample taken during the patient's admission. The positive result was reported fifteen days subsequent to autopsy.