Correct!
2. Obtain transthoracic percutaneous needle biopsy
Although the nodule showed no significant tracer accumulation at 18FDG-PET and showed a small focus of calcification- both strong predictors of a benign etiology- the lesion has clearly shown growth and developed cavitation, indicating that it is an active process. The growth and cavitation are certainly not specific for malignancy- active infection, most likely fungal or mycobacterial, could present in this fashion. Because the lesion is active and both malignancies and infections, the latter requiring mutually exclusive therapies that prohibit an empiric approach, suggest that a tissue diagnosis is required. The lesion should be amenable to percutaneous transthoracic fine needle aspiration biopsy, and that approach is the least invasive of the options listed, although clearly the surgical options would provide a definitive diagnosis. In fact, one could argue that the pre-test probability of primarily malignancy is high enough in this patient- a growing cavitary nodule in an adult with a significant smoking history, with an 18FDG-PET scan showing no metastatic disease- to resect the right upper lobe on the assumption that the lesion is malignant. Nevertheless, in practice, even high pre-test probability lung nodules undergo pre-operative tissue sampling to confirm a malignant diagnosis before definitive surgical therapy is often undertaken. Given that the nodule has shown growth, serial evaluation to exclude further growth is generally a less rewarding approach.
The patient was referred to thoracic surgery and underwent repeat 18FDG-PET scanning, as part of the pre-operative evaluation which now showed the right upper lobe nodule to be hypermetabolic but no increased metabolic activity was seen in the regional or mediastinal lymph nodes (Figure 6).
Figure 6. Representative images from the repeat 18FDG-PET scan done as part of the pre-operative evaluation showing increased tracer utilization in the right upper lobe nodule (standard uptake value = 4.7). No evidence of increased mediastinal or peribronchial tracer activity is noted.
The right upper lobe was resected, showing moderately-differentiated adenocarcinoma without lymph node involvement. The right upper lobe also showed areas of necrotizing granuloma formation, areas of organizing pneumonia, and patchy bronchiolocentric scars.
Diagnosis: Primary bronchogenic malignancy- moderately differentiated adenocarcinoma (with initially false negative 18FDG-PET results)
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References