Non-resolving or slowly resolving pulmonary infiltrates in spite of administering adequate antimicrobial therapy are a clinical diagnostic challenge for physicians. The rate of radiographic resolution varies with the patients' age, the underlying comorbidities, the extent of radiographic involvement, the functional status and the causal pathogens. It is important to differentiate non-resolving or slowly resolving bacterial pneumonia from other uncommon infectious pneumonias or malignancies that require invasive diagnostic techniques to confirm the diagnosis. Bronchioloalveolar carcinoma can present with various clinical and radiographic features. Unfortunately, the radiographic similarity of consolidative BAC to pneumonia often leads to an incorrect diagnosis of pneumonia and possibly significant delays in obtaining appropriate diagnostic studies. We describe here a case of a mixed adenocarcinoma and bronchioloalveolar carcinoma that was initially diagnosed as pneumonia due to the consolidation pattern on the radiography and the patient's initial improvement with antibiotic treatment.