Time sensitivity factor of single pulmonary nodule: a new cancer characteristic metabolic parameter by (18) F-FDG PET

Why do a lung biopsy for benign lesions?

BACKGROUND

Transthoracic needle biopsy of lung lesions is a well-established procedure for the diagnosis of lung lesions. The literature focuses on the diagnosis of malignant lesions with an often reported accuracy rate of more than 90%. Experience showed that biopsy can identify sometimes incidentally, also benign lesions. There are many reasons why a biopsy is performed for a "benign lesion." First of all, it may be an unexpected diagnosis, as some benign pathologies may have misleading presentations, that are very similar to lung cancer, otherwise the reason is only to make a diagnosis of exclusion, which leads to the benign pathology already being considered in the differential diagnosis.

METHODS

This study was designed as a retrospective single-center study. We selected from our database all the lung biopsies performed under CT guidance, from 2015 to 2019 and retrospectively analysed the histological data. We selected only benign lesions describing the imaging feature and differential diagnosis with lung malignancy.

RESULTS

In our patient population, among the 969 of them that underwent biopsy, we identified 93 benign lesions (10%). Hamartomas, granulomas, slow-resolving pneumonia and cryptogenic organizing pneumonia are the pathologies that most frequently can misinterpratedas lung cancer.

CONCLUSIONS

In this brief report we want to show the percentage and type of benign lesions that are found in our lung trans-thoracic biopsy population. Among these, we identified the three most frequent benign lesions that most frequently enter the differential diagnosis with lung malignant lesions describing the classic and atypical imaging findings.

Evaluation of physiologic and abnormal glucose uptake in palatine tonsils: differential diagnostics with sequential dual-time-point 2-deoxy-2-[18F]FDG PET/CT

BACKGROUND

The aim of this article was to evaluate the usefulness of sequential dual-time-point 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (DTP [18F]FDG PET/CT) in distinguishing physiologic, inflammatory and malignant palatine tonsils as difficult to differentiate in the oncological practice.

METHODS

A total of 90 patients before the treatment underwent sequential DTP [18F]FDG PET/CT examinations. We analyzed 104 structures in 90 patients: 31 physiologic tonsils, 28 histopathologically confirmed inflammatory tonsils of non-specified origin, 31 histopathologically confirmed palatine tonsils cancer and 14 non-malignant contralateral tonsils in patients with histopathologically confirmed unilateral palatine tonsil malignancy. Patients underwent sequential [18F]FDG PET/CT examinations at 60 and 90 minutes post-injection of the [18F]FDG. We analyzed the SUVmax and SUVmean values at 60 and 90 minutes post-injection changes over time and the Retention Index (RI-SUVmax). To find the predictive SUV value and the RI cut-off between physiology, inflammatory and malignancy, we used the ROC analysis.

RESULTS

The average SUVmax values at 60 and 90minutes post-injection within physiologic palatine tonsils were 1.36±0.26 and 1.31±0.26, respectively, P>0.05. The average SUVmax values at 60 and 90 minutes post-injection within inflammatory and malignant tonsils were 3.74±1.45, 3.80±1.47 (P>0.05) and 5.19±2.19, 5.81±2.50 (P<0.05), respectively. The RI-SUVmax fluctuation over time were 5±28% within physiologic, -4±11% within contralateral non-malignant tonsils in patients with one tonsil involved, 2±11% within inflammatory and 13±13% within malignant tonsils.

CONCLUSIONS

The sequential dual-time-point [18F]FDG PET/CT examinations may increase the sensitivity and the specificity of the PET/CT method in differential palatine tonsils diagnosis.