Background Lung involvement in patients with coronavirus disease 2019 (COVID-19) undergoing PET-CT has been previously reported. However, FDG uptake outside lung parenchyma was poorly characterized in detail. We evaluated the extraparenchymal lung involvement in asymptomatic cancer patients with COVID-19 pneumonia through 18 F-FDG PET-CT. Methods A total of 1079 oncologic 18 F-FDG PET-CT were performed between February 2 and May 18, 2020. Confirmed COVID-19 pneumonia was defined as characteristic ground-glass bilateral CT infiltrates and positive genetic/serologic tests. Nonmetastatic extra-parenchymal lung PET-CT findings were evaluated through qualitative (visual), quantitative (measurements on CT), and semiquantitative (maximum standardized uptake value: SUVmax on PET) interpretation. Clinical data, blood tests, and PET-CT results were compared between patients with and without COVID-19 pneumonia. Results A total of 23 18 F-FDG PET-CT scans with pulmonary infiltrates suggestive of COVID-19 and available laboratory data were included: 14 positive (cases) and 9 negative (controls) for COVID-19 infection, representing a low prevalence of COVID-19 pneumonia (1.3%). Serum lactate dehydrogenase and D-dimers tended to be increased in COVID-19 cases. Extraparenchymal lung findings were found in 42.9% of patients with COVID-19, most frequently as mediastinal and hilar nodes with 18 F-FDG uptake (35.7%), followed by incidental pulmonary embolism in two patients (14.3%). In the control group, extrapulmonary findings were observed in a single patient (11.1%) with 18 F-FDG uptake located to mediastinal, hilar, and cervical nodes. Nasopharyngeal and hepatic SUVmax were similar in both groups. Conclusion In cancer patients with asymptomatic COVID-19 pneumonia, 18 F-FDG PET-CT findings are more frequently limited to thoracic structures, suggesting that an early and silent distant involvement is very rare. Pulmonary embolism is a frequent and potentially severe finding raising special concern. PET-CT can provide new pathogenic insights about this novel disease.

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We present the planar lymphoscintigraphies and SPECT/CT images of a 60-year-old man diagnosed as having melanoma (Breslow 1.8 mm) in left parietal scalp, close to head midline. Sentinel lymph node biopsy using 99mTc-tilmanocept was performed, but the surgery was canceled. Two weeks later, sentinel lymph node biopsy was repeated, but using the hybrid radiotracer indocyanine green–99mTc-albumin nanocolloid. The lymphatic drainage in left laterocervical region was similar with these 2 radiotracers, but on the right side, more sentinel lymph nodes were detected with nanocolloid compared with tilmanocept.

Aim We aimed to determine the frequency and clinical significance of breast incidental uptake (BIU) detected through fluorine-18 fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) in a single, high-load center. Patients and methods In this retrospective study, we analyzed a total of 13 763 PET/CT studies performed from January 2017 to January 2020. After excluding 3148 scans, the maximum standardized uptake value (SUVmax) and maximum diameter (cm) of each BIU were measured. Clinical management, ultrasound/mammography and pathology reports were analyzed. Results We found BIU in 27 scans of 26 patients (0.3% of the studies). Mean age was 62.2 years and 88.5% were women; 84.6% underwent PET/CT for oncological indications. Ultrasound/mammography was consequently performed in 23 patients (88.5%), and histological correlations were available for Breast Imaging Reporting and Data System categories 4 and 5. Finally, lesions were benign in 14 patients (60.9%; two of them with low/intermediate risk of malignancy) and malignant in nine patients (39.1%). The remaining three patients had no ultrasound/mammography reports. Mean SUVmax of benign and malignant lesions were 2.6 ± 1.4 and 5.8 ± 3.5, respectively (P = 0.002). Considering a SUVmax cut-off value of 4.0, the sensitivity and specificity for differentiating benign vs. malignant lesions were 67 and 93%, respectively. Benign lesions were smaller than malignant in CT (maximum diameter:1.3 ± 0.5 cm vs. 2.0 ± 1.0 cm, P = 0.02). Conclusion Although BIU detected by 18F-FDG PET/CT is infrequently found, the risk of malignancy remains very high (39.1%). Both SUVmax and maximum diameter were greater in malignant than in benign lesions. An exhaustive study with ultrasound/mammography and selective histopathological correlation is mandatory after BIU findings, even in small lesions.

Early detection of primary lesion with isolated axillary lymph node metastasis without any clinical or radiological evidence of tumour is still a pending issue. It is important to offer these patients a better management and survival. The definition of occult breast carcinoma is redefined as radiological diagnostic techniques progress. We emphasize the contribution of whole-body fluorine-18 fluorodeoxyglucose positron emission tomography associated with computed tomography for staging, surgical approach and adjuvant treatments recommendations for these patients.