key: cord-0848945-vg47ugax
authors: Ferrando-Castagnetto, Federico; Wakfie-Corieh, Cristina Gamila; García, Alba María Blanes; García-Esquinas, Martha García; Caro, Rosa María Couto; Delgado, José Luis Carreras
title: Incidental and simultaneous finding of pulmonary thrombus and COVID-19 pneumonia in a cancer patient derived to (18)F-FDG PET/CT. New pathophysiological insights from hybrid imaging.
date: 2020-07-16
journal: Radiol Case Rep
DOI: 10.1016/j.radcr.2020.07.032
sha: 64bc8ef53feebcee9b67bcdcbdddb1493f4121ef
doc_id: 848945
cord_uid: vg47ugax

Cancer patients require a careful clinical follow-up during the Coronavirus Disease 2019 (COVID-19) pandemic. Although hybrid fluorine-18 Fluorodeoxyglucose ((18)F-FDG) Positron Emission Tomography-Computed Tomography (PET/TC) is not routinely used in the management of COVID-19 patients, it could play a complementary role of other laboratory and radiological data in selected cases. We describe an asymptomatic cancer patient derived to (18)F-FDGPET/CT with simultaneous findings of COVID-19 pneumonia and pulmonary thrombus, discussing its possible mechanisms and prognostic implications.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the Coronavirus Disease 2019 (COVID-19) spread quickly all over the world from a first outbreak in Wuhan, China. Most patients infected from COVID-19 present as asymptomatic or mild forms, but some develop severe complications as acute respiratory distress syndrome, kidney or cardiac injury or thromboembolic events [1] . As large case series confirmed the higher risk of these complications in cancer patients, [2] a careful clinical follow-up, selecting most useful diagnostic techniques and deciding the best opportunity for onco-specific treatments is very relevant in this subpopulation.

Although fluorine-18 Fluorodeoxyglucose ( 18 F-FDG) Positron Emission Tomography-Computed Tomography (PET/CT) is not routinely used in the management of COVID-19 patients, it could play a complementary role of other laboratory and radiological data in selected cases [3] . In addition, whole-body PET/CT can detect several non-expected complications of COVID-19 and provide new insights about pathogenic and host response against SARS-CoV-2 infection. We describe an asymptomatic cancer patient with simultaneous findings of COVID-19 pneumonia and pulmonary thrombus in 18 F-FDGPET/CT, discussing its possible mechanisms and prognostic implications.

An 88-year-old man with a medical history significant for stable angina pectoris and chronic moderate aortic insufficiency, carrying left atrium and stage IV melanoma. 18 

The true prevalence of COVID-19 pneumonia in asymptomatic cancer patients referred to PET/CT is unknown. Only available data is derived from a few small case series of subjects with suspicious tomographic findings and none/partial laboratory confirmation [4] [5] [6] , reporting a frequency of tomographic suggestive findings ranging broadly from 8.5 % [5] to 39% [6] , and confirmed COVID-19 pneumonia in 4 and 8% of studies, respectively.

The biochemical profile was highly suggestive of COVID-19 pneumonia in our case, in line with the results of a recent meta-analysis [7] . These common, non-specific laboratory abnormalities are related to the cytokine storm brought on by SARS-CoV-2 infection, with progressive activation of neutrophils, monocytes and T-helper cells. Chest CT suggested this infection while laboratory results were available. The quasi optimal sensitivity of CT (98%) supports its use for screening COVID-19 in suspected cases, particularly in those whom first genetic essay was negative [8] . The inflammatory host response against viral infections as SARS-CoV-2 could induce a prothrombotic state in some patients [9] , with increased levels of D-dimers in 36% of patients with COVID-19 pneumonia [10] , that could be explained by the imbalance between procoagulant and anticoagulant homeostatic mechanisms.

The incidental diagnosis of lung infiltrates and PE in cancer patients with COVID-19 is a very unusual finding observed in in PET/CT. This diagnostic association has been scarcely documented, mainly through anecdotical reports of complicated symptomatic patients [11] .

We think these simultaneous pulmonary changes in the absence of symptoms provide some clues about pathogenic of COVID-19, and also raise special prognostic and therapeutics concerns. Thrombotic complications were observed in 31% of critically ill patients with COVID-19 [12] , but their prognostic implications have not been defined in asymptomatic cancer patients. While high-risk acquired thrombotic factors as age, cardiac disease and cancer suggest an embolic mechanism in our patient, the temporal concomitance raise the hypothesis that a local prothrombotic environment could favors the development of in situ arterial thrombosis. Another evidence is provided by CT findings of an interstitial COVID-19 pneumonia located in the same affected lobe than vascular involvement. This uncommon mechanism is suggested by the presence of intra-alveolar fibrin clots observed in animals and humans with severe respiratory forms of COVID-19 [9] . However, as deep venous thrombosis was not explored during the pandemic clinical setting and high-resolution CT angiography scan is not applied during PET/CT scans, it was not possible to accurately define if these imaging changes respond to a localized in situ thrombosis or a true PE.

Whatever the mechanism, it is reasonable to consider this event as a marker of poor prognosis. In the meanwhile, our case report advocates raising the suspicious of an underlying thromboembolic event in asymptomatic cancer patients with COVID-19 pneumonia exhibiting very high levels of serum D-dimers. Once confirmed, these patients should be treated with non-fractioned low weight heparin or new oral anticoagulants, in accordance to the updated clinical guidelines.

During the high local rate of COVID-19 infection in Spain, the health system optimized the allocation of resources while applying the recommendations of scientific societies, with the intention of carrying out safer diagnostic and therapeutic procedures. Despite this situation, some priority oncological indications were still being carried out in selected patients. Our clinical case highlights that medical staff should pay special attention to incidental findings suggesting COVID-19 pneumonia and/or PE in PET/CT studies of cancer patients.

Clinical features of patients infected with 2019 novel coronavirus in Wuhan

Clinical characteristics of COVID-19-infected cancer patients: A retrospective case study in three hospitals within Wuhan

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Incidental findings suggestive of Covid-19 in asymptomatic patients undergoing nuclear medicine procedures in a high prevalence region

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On axial images (lung and mediastinal windows, B and C), a thrombus was depicted within a left lower lobe segmental branch (red arrowhead) in addition to basal right lung infiltrates (white arrowheads). Axial CT (lung window, D), PET-CT and PET images show bilateral ground-glass opacities and lineal right subpleural bands