Incidental diagnosis of medullary thyroid carcinoma due to persistently elevated procalcitonin in a patient with COVID-19 pneumonia:A case report

BACKGROUND Procalcitonin(Pct)is a common biomarker in clinical practice,especially in the era of coronavirus disease 2019(COVID-19)infection.Although it is frequently used for the diagnosis and prognostication of bacterial infections or sepsis,it is also elevated in a few other conditions,including medullary thyroid carcinoma(MTC).CASE SUMMARY A 43-year-old female presented with moderately severe COVID-19 pneumonia in April 2021.She gradually recovered clinically;however,despite normalization of other inflammatory markers,Pct levels remained persistently elevated.Further workup identified the cause as left lobe MTC with locoregional metastasis.Calcitonin levels were high,and carcinoembryonic antigen levels were normal.The patient underwent total thyroidectomy and neck dissection,which was followed by another radical neck dissection due to residual disease.Currently,she is doing well,nearly having completed her course of external beam radiotherapy with no recurrence.Pct is well documented as a screening tool for MTC,especially because of its stable nature compared to calcitonin in the community settings.It is important to keep in mind the differential diagnosis of MTC in patients with persistently elevated Pct levels despite normal levels of other acute phase reactants.To the best of our knowledge,this is the first report from Asia of such an incidental diagnosis of MTC due to persistently elevated Pct levels in a patient with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection.CONCLUSION Persistently elevated Pct levels can occur in any pro-inflammatory state including infections,sepsis,or acute respiratory distress syndrome.In the current setting,SARS-CoV-2 infection is one such clinical scenario,and in rare situations of persistent elevation,MTC may need to be ruled out.

Electric-field driven stability control of skyrmions in an ultrathin transition-metal film

To realize future spintronic applications with magnetic skyrmions—topologically nontrivial swirling spin structures—it is essential to achieve efficient writing and deleting capabilities of these quasi-particles.Electric-field assisted nucleation and annihilation is a promising route,however,the understanding of the underlying microscopic mechanisms is still limited.Here,we show how the stability of individual magnetic skyrmions in an ultrathin transition-metal film can be controlled via external electric fields.We demonstrate based on density functional theory that it is important to consider the changes of all interactions with electric field,i.e.,the pair-wise exchange,the Dzyaloshinskii–Moriya interaction,the magnetocrystalline anisotropy energy,and the higher-order exchange interactions.The energy barriers for electric-field assisted skyrmion writing and deleting obtained via atomistic spin simulations vary by up to a factor of three more than the variations of the interactions calculated from first-principles.This surprising effect originates from the electric-field dependent size of metastable skyrmions at a fixed magnetic field.The large changes in lifetimes allow the possibility of electric-field assisted thermally activated writing and deleting of skyrmions.