Cannon-Ball Appearance Of COVID-19 Pneumonia: A Novel Presentation Mimicking Malignancy

Diagnosis of COVID-19 is an increasingly challenging task during a pandemic where symptoms are beguiling due to a wide array of symptomatology. Radiologic diagnosis plays a vital role not only in diagnosis but in early assessment and triage of suspected patients with COVID-19 pneumonia. Typically, bilateral ground-glass opacities are considered high-risk and pathognomonic findings for diagnosis. However, COVID-19 is notorious for varying radiologic presentation as well. We describe a case of cannon-ball appearance of COVID-19 pneumonia which has not been described previously in the literature and is a novel finding.


Introduction
However, despite the wide array of findings on CT scan, cannon-ball appearance has not been reported per our review of the literature.
Cannon-ball appearance in radiology describes the presentation of multiple rounds, nodular opacities with well-defined borders [8].The most common cause of cannonball appearance is metastatic malignancy; however, other infectious diseases such as pulmonary tuberculosis, histoplasmosis, cryptococcosis, and nocardiosis can also present with granulomas that match this finding [9].We present a case of a COVID-19 positive patient who misleadingly presented with cannonball appearance on CT scan, causing a management dilemma.

Case
A 35-year-old man with a past medical history of type 1 diabetes mellitus, Factor V Leiden deficiency, and deep vein thrombosis (DVT) (for which he was on anticoagulants with warfarin) presented via Emergency Medical Services (EMS) with altered mental status and respiratory distress.He does not smoke nor drink alcohol and denied fever, chills, cough, sore throat, recent viral illness, recent travel, or sick contacts.He was treated two months prior for sepsis secondary to osteomyelitis of the foot, which he recovered well from on the follow-up visit.On presentation to the emergency department, the patient was noted to be obese, afebrile, tachycardic, hypotensive     COVID-19 manifests most commonly with bilateral and multilobar lesions, with single lung and lobe lesions presenting less commonly.
The most common type of lesion density found was ground-glass opacities, seen in this patient case, followed by air bronchogram signs, crazy-paving pattern, and consolidation.This study also categorized the lesions by shape, where patchy was the most common, followed by spider web sign, cord-like, and nodular, seen in this patient.Other radiological signs that accompanied these lesions were pleural thickening, followed by more rare signs of lymphadenopathy and pleural effusion [5]. Another Since late December of 2019, the pandemic is known as coronavirus disease 2019 (COVID-19) has been overwhelming healthcare systems globally as it has rapidly spread throughout over 200 different countries.The World Health Organization (WHO) has declared COVID-19 as a Public Health Emergency of International Concern (PHEIC) [1] in January of 2020, and now reports that there are over 40 million confirmed cases with over 1 million deaths worldwide as of October 18, 2020 [2].COVID-19 patients present with nonspecific symptoms of fever, cough, and shortness of breath, which makes early detection and containment difficult.Even if COVID-19 is suspected early on, the current reference standard for diagnosis is a real-time reverse transcriptase-polymerase chain reaction (RT-PCR), which has shown to yield significant falsenegative results [3].One study reports a high false-negative rate ranging from 68-100 % on the first 4 days of infection prior to symptom onset, dropping only to 21 % one week after infection [4].Consequently, an alternative modality such as CT imaging for detection and diagnosis may prove to be very valuable for treatment purposes and more importantly, limiting and controlling the spread of COVID-19.Chest CT imaging has the potential to both detect infection and determine its severity according to a series of studies [5].This alternative method of detection is especially useful in the case of an ambiguous or false-negative RT-PCR result and help validate true-positive results, demonstrated by a study that found 5 of 167 patients with positive chest CT and negative RT-PCR results test positive for COVID-19 days later [6].According to meta-analyses, COVID-19 on chest CT commonly presents with ground glass opacities in 86% of cases, consolidation in 47 % of cases, and air bronchogram sign in 46 % of cases [7].By identifying these common patterns and being cognizant of new and potentially coronavirusspecific signs, we hope to add another crucial layer of testing to the diagnostic process of COVID-19.
Sheikh T, Tsai L, Hasan S, Tewari P, Assaly R (2020) Cannon-Ball Appearance Of COVID-19 Pneumonia: A Novel Presentation Mimicking Malignancy.J Med Case Rep Case Series 1(4): https://doi.org/10.38207/JMCRCS2208185with a blood pressure of 80/50 mmHg, and tachypneic with 89 % oxygen saturation on room air.He was placed on oxygen by highflow nasal cannula.A chest exam revealed rhonchi and decreased breath sounds bilaterally.Arterial blood gas test (ABG) showed worsening acidosis with PaO2 at 70 mmHg and PaCO2 at 50 mmHg.He developed grunting respirations and was intubated for airway protection and respiratory distress.Labs showed lymphocytes at 7.5x10 9 /L with lymphopenia of 8.5 %, procalcitonin at 1.72 ng/mL, ferritin at 453 ng/mL, D-dimer at 195 ng/mL, CRP at 10.3 mg/dL, LDH at 403 U/L, lactate at 2.1 mmol/L, and creatinine at 1.45 mg/dL.Troponin and BNP was negative while an echocardiogram (EKG)showed sinus tachycardia.The viral respiratory pathogen panel was negative, and urinalysis was unremarkable.The chest X-ray showed a cannon-ball appearance in all lung fields bilaterally (Figure1), which was a new finding compared to the normal X-ray from prior admission.

Figure 1 :
Figure 1: AP Supine chest radiograph showing a mechanically ventilated patient with multifocal bilateral nodular consolidation resembling cannon-ball appearance.

Figure 2 :
Figure 2: Non-contrasted computed tomography axial images of the chest showing multifocal bilateral nodular consolidations with panlobular affectation and only minimal interspersed ground glass opacities.

Figure 3 :
Figure 3: Non-contrasted computed tomography soft tissue window axial and coronal images of the chest showing multifocal bilateral nodularity and consolidation with panlobular affection.

Figure 4 :
Figure 4: Non-contrasted computed tomography axial images of the chest showing resolving nodularity with some residual ground glass opacity (solid black arrow), pulmonary nodules (broken black arrow) and bronchiectasis (curved black arrow).
The ground glass opacities saw in the right lobes of this the patient indicates that his radiological presentation is quite common among COVID-19 patients, aside from his cannon-ball opacities.This serious functional impairment of the lungs is seen on chest CT as areas of consolidation.As a result, the presence and nature of consolidation areas seen on CT imaging is another marker for determining the severity and progression of COVID-19.With this case finding of cannon-ball appearance on CT imaging of COVID-19, it adds yet another avenue to the unique presentations of COVID-19, necessitating distinguishing it from other forms of viral pneumonia.Cannon-ball appearance primarily signifies malignancy and sometimes other infectious diseases such as pulmonary tuberculosis, histoplasmosis, or cryptococcosis.Because COVID-19 is not notorious for cannon-ball appearance, pulmonary isolation may be delayed, potentially endangering medical personnel to exposure.COVID-19 becomes a diagnosis of exclusion for centers lacking testing since it is possible to rule out the other causes.Nonetheless, further data and studies are needed to fully understand this finding and to recognize it as a valid radiological sign for COVID-19.
[7]gression of the disease[3].Similar to the first meta-analysis, this analysis also found that the most common lesion was ground-glass opacities without consolidation, as it affected 86 % of patients[7].The potential explanation for this common finding is that these patients are either in the early phase of viral infection or that the immune system has successfully limited the spread of disease and absorbed parts of the consolidation area [10].