Common clinical manifestations of COVID–19 include fever, cough, dyspnoea, myalgia and fatigue. None of our patients had symptoms of infection.
The first two patients were a 54-year-old man who was referred to our division to stage a non-Hodgkin lymphoma and a 61-year-old man who presented lung, lymph nodes and brain lesions suspected for cancer of unknown primary origin.
In patient #1 PET/CT scan revealed pathological uptake in right inguinal lymph nodes (Fig. 1a - boxe). There was also intense 18F-FDG uptake on multiple bilateral subsegmental peripheral patchy ground-glass opacities (GGOs) with obscure boundaries and mainly subpleural distribution (Fig. 1a and b - black arrows) and areas of focal consolidation in the upper lobes (Fig. 1b - red arrows). Moreover, multiple FDG-avid lymph nodes in mediastinum and left subclavian region were detected (Fig. 1a - green arrow).
Similarly, in patient #2 the PET/CT revealed intense 18F-FDG uptake on multiple peripheral GGOs (Fig. 1c and d - black arrows) in the left lower lobe and areas of focal consolidation in the upper lobes (Fig. 1c - red arrow). Multiple FDG-positive areas were also identified in mediastinal, carenal, subcarenal and hilar lymph nodes (Fig. 1c - green arrow).
These findings were consistent with interstitial pneumonia and suggested a diagnosis of COVID–19, that was also confirmed by an experienced radiologist.
Patient #3 was a 48-year-old man with a stage IV lung cancer already treated with neoadjuvant chemotherapy, radiotherapy, surgery and adjuvant chemotherapy in 2015, nivolumab for a subsequent lung relapse and radiotherapy on right retro-bronchial lymph nodes metastases in January 2020. He performed the exam for disease re-staging. The PET/CT scan showed radiotracer uptake in the treated lymph nodes, due to the recent radiotherapy (Fig. 2a - boxe). There were also intense accumulation on a focal consolidation in the upper left lobe (Fig 2b—red arrows), multiple peripheral GGOs with interstitial thickening and thin fibrous stripes in the left lower lobe (Fig. 2a, b and c - black arrows) and multiple FDG-uptake in mediastinal and left hilar lymph nodes (Fig. 2a - green arrow).
Patient #4 was a 54-year-old man with right cheek melanoma who underwent surgery in 2017 and was treated with pembrolizumab due to the subsequent appearance of lung metastases, with complete response. The PET/CT was required as a follow-up and, as compared to the previous one, revealed the persistence of intense uptake on subpleural pseudonodular thickenings in the lower right lobe, doubtful for persistence of neoplastic disease. The low-dose CT scan revealed also the presence of multiple small subpleural GGOs and opacities bilaterally without 18F-FDG uptake (Fig. 3a, b and c - black arrows).
Finally, patient #5 was referred to our division to follow-up a tongue carcinoma submitted to surgery in 2016–2017 and adjuvant chemo- and radiotherapy. The PET/CT revealed intense 18F-FDG uptake on multiple peripheral GGOs (Fig. 4a, b and c - black arrows) in both lower lobes and area of focal consolidation in the right upper lobe (Fig. 4a - red arrow). Focal FDG-positive area was also identified in right hilar lymph node (Fig. 4b - green arrows).
Diagnostic CT scan subsequently performed for patient #3, #4 and #5, and evaluated by an experienced radiologist, confirmed the PET/CT findings of suspected COVID–19 (Fig. 2d, 3d and 4d - black arrows).
For the first three patients, following the operating instructions dictated by the Medical Office of our hospital, we called the European emergency number (112), first public safety answering point. Patients #1 and #2 were taken to COVID-dedicated hospital facilities by ambulance, tested for SARS-CoV–2 and then sent home for 14 day self-isolation period.
In view of the worsening of the emergency situation, the subsequent scarcity of resources and the need for their adequate allocation, patient #3 was not taken into care by a COVID-dedicated hospital. The nuclear medicine physician who evaluated his PET/CT scan and detected the suspect lung lesions, instead, contacted his lung specialist who provided to send him to a centre where he performed the test for SARS-CoV–2.
Then, in agreement with our Medical Office, we developed and followed a different procedure for the fourth and fifth patient. The test was performed in our hospital by a dedicated nurse and the patient was sent back home after being instructed on the behaviors to follow in order to avoid spreading the infection (social distancing, hand hygiene and cough etiquette), with a pamphlet and a clinical diary created for this special purpose.
The SARS-CoV–2 test yielded positive results in all five patients.