INTRODUCTION: Cytology and histopatholgoy remain the “gold standards” for the diagnosis of lung cancer. However, from time to time occassional false positives result in unnecessary surgery, therapeutic interventions or patient anxiety. We describe a case of a pulmonary infarct mimicking bronchogenic carcinoma.
CASE PRESENTATION: A 44-year-old Caucasian female presented with cough, fever, and shortness of breath of one week duration. She was initially diagnosed with a viral upper respiratory tract infection in the emergency department and sent home. Evaluation of her chest radiograph revealed a 3.5cm lesion in the right middle lobe. Computerized tomography (CT) examination follow-up. Chest CT showed a thin-walled focal cystic lesion in the right middle lobe with an adjacent spiculated nodule and mediastinal lymph node enlargement. Her past medical history was unremarkable, and she denied any constitutional symptoms of weight loss, hemoptysis, or recent travel. She was a smoker of ½ pack per day for fifteen years. She was started on levofloxacin although no organisms were identified in the sputum culture. Fiberoptic bronchoscopy was performed for diagnosis. Cytological review of the bronchial brushing, transbronchial needle biopsy of the pre-carinal lymph node, bronchioalveolar lavage (BAL), and common trap were all positive for atypical cells suspicious for non-small cell carcinoma. External review of the specimens also agreed with the report. She underwent a mediastinoscopy. Frozen section of the enlarged lymph node did not show evidence of malignancy, and she subsequently had a right middle lobectomy for surgical diagnosis and curative treatment. Pathology of the right middle lobe showed no malignancy, but rather a recent pulmonary infarct measuring 2.5cm in greatest dimension.
DISCUSSIONS: Pulmonary infarction has a variety of etiology such as pulmonary thromboembolism, vasculitis, infections, sickle cell, etc. Pulmonary infarction usually appears as a peripheral wedge-shaped parenchymal opacity on chest radiographs. There have been reported cases of pulmonary infarct misdiagnosed as lung carcincoma on cytology (1-2). Bewtra and colleagues (1) investigated the incidence of atypical cells in sputum cytology in patients with radiologically proven pulmonary emboli in a prospective, double-blinded, randomized study. The study showed 44% had atypical cells during the second and third weeks of illness. Abnormal cytologic features consisted of clusters of glandular cells with enlarged nuclei and macronucleoli. These abnormal cells were differentiated from malignant cells by their smaller number, transient appearance, and lack of solitary atypical cells. Tissue histology showed reactive reparative peripheral bronchioloalveolar cells appearing as atypical. Similar atypical cells can be seen around scars, interstitial fibrosis, organizing pneumonia, bronchiectatic cavities, and following radiation and chemotherapy. Detailed clinical information regarding presence of absences of these conditions need to be provided to the cytologist to avoid such false positive diagnosis.
CONCLUSION: The differential diagnosis when confronted with a lung mass include a wide spectrum of disease processes. It is important to consider pulmonary infarct as part of the differential diagnosis of lung malignancy. Even when cytology indicates malignancy, clinical correlation is important. False-positive cytology does exist and pulmonary infarct has been misdiagnosed. Our case demonstrates how difficult assessing a lung mass can be.
DISCLOSURE: Richard Le, None.