Wednesday, 27 April 2011
Pulmonary aspergillosis: an alternative diagnosis to lung cancer after a positive PET scan.
Positron emission tomography (PET) scans are used in the clinic to assist with diagnosis and staging in lung cancer. False positive scans can arise due to inflammation and infections. The clinical features of pulmonary aspergillosis may include single or multiple nodules and possible cavities which resembles those of lung cancer.
A recent publication (Baxter et al 2011) investigating 10 cases of pulmonary aspergillosis including both allergic, chronic and aspergilloma type cases - has demonstrated that increased radioisotope uptake on PET scans can be attributed to their aspergillosis. All types of aspergillosis studied could lead to a possible positive PET scan.
Thus aspergillosis is a possible cause of false positivity by PET scanning. Since it is vital not to miss a diagnosis of lung cancer other histological diagnostic techniques must be used . Open surgical routes of biopsy entail risk factors for the patient - but the advent of CT guided biopsy as a non surgical method of tissue diagnosis is preferable when appropriate - and may be combined with serology and PCR techniques to confirm or eliminate a diagnosis of aspergillosis or malignancy.