Bronchioloalveolar carcinoma (BAC) accounts for 2.6-4.3% of all lung cancers with incidence rising especially in females and non –smokers (1). We report an unusual presentation of BAC masquerading as bilateral community acquired pneumonia (CAP) with pseudo-abscess formation.
A 30-year-old female, with a 12 one-pack-year smoking and no prior medical history, presented with a history of flu-like symptoms, cough and right-sided pleuritic chest pain. Chest radiograph (CXR) revealed a right lower lobe (RLL) infiltrate, and she was treated with 10 days of levofloxacin. Repeat CXR demonstrated a large RLL cavity. A chest CT scan confirmed a 2 cm cavity with an air-fluid level and surrounding consolidation. A pigtail catheter was placed and opaque fluid was drained from the cavity initially culture negative, with an unspeciated gram negative rod isolated two weeks later. She was then treated with a six-week course of amoxicillin-clavunalic acid, ciprofloxacin and metronidazole. Repeat CT revealed persistence of a fluid filled thick walled RLL cavity, progressive dense consolidation through out the RLL, as well as new thick walled small cavities and parenchymal infiltrate within the left lung. Standard therapy for lung abscess was deemed a failure and she was referred to our center.Repeat CT revealed an increase in the diameter of the RLL cavity (4cms) with new right upper lobe involvement (figure 1). She was afebrile and chest examination revealed reduced breath sounds at the right lung base with fine rales in the RLL. Complete blood count was normal and serum ANA, ANCA, rheumatoid factor and HIV antibody were negative. Serum Immunoglobulins were normal. Fungal serologies were negative. Bronchoscopy revealed no endobronchial lesions and cultures and cytology were negative. A course of intravenous vancomycin and ceftazidime was commenced and repeat CT was performed 3 weeks later revealing stable appearance of RLL cavity with progression of disease in the right middle and upper lobe. At that time, a left upper lobe thorascopic wedge excision was performed and pathology revealed non-mucinous adenocarcinoma with a bronchioloalveolar growth pattern throughout the specimen (figure 2). The tumor was focally positive for TTF-1 and negative for estrogen receptor consistent with BAC. She was commenced on a course of erlotinib 150 mg/day. Repeat CT scan after 4 weeks of therapy revealed stable disease, but progression of disease was noted after 8 weeks. She was therefore switched to systemic chemotherapy.
Patients with BAC can present with symptoms such as cough, chest pain and sputum production making it difficult to distinguish from pneumonia. BAC typically arises in the lung periphery and grows along the alveolar wall without, by definition, destruction of the underlying parenchyma. The radiographic presentation of BAC is varied. The most common presentation is the solitary pulmonary nodule, followed by an infiltrate involving one lung with or without air bronchograms. Cavitation is rare, occurring in about 10% of cases (2). BAC masquerading as a large pseudo-abscess with cavitary pneumonia has not been previously described.
BAC can present with a variety of clinical and radiographic features and should be included in the differential diagnoses of CAP with cavitation. Biopsy or cytological examination should always be considered when patients with CAP do not respond to conventional antibiotic therapy.
Marcus Kennedy, None.