The other presents aggressively with multiple nodules or as dense consolidations involving single lobes or entire lungs, mimicking community acquired pneumonia or pulmonary edema in radiographic appearance. Because BAC arises in the periphery, distant from bronchi, it evolves asymptomatically and frequently remains undetected until a chest x-ray is obtained for unrelated reasons. As the disease advances, typical symptoms include cough, chest pain, dyspnea, weight loss, and hemoptysis. The diagnostic criteria for BAC are primarily histologic. Because it may be difficult to differentiate BAC from metastatic disease, extrathoracic adenocarcinoma must be ruled out.
Histologic diagnosis is made on bronchial washings or transbronchial or transthoracic biopsy.
Typical of many cases of BAC, this patient had few pulmonary and no systemic symptoms suggestive of a carcinomatous process in his lungs. In fact, he had sought medical care for an unrelated concern, and the lobar infiltrate was discovered incidentally. Because the unexplained infiltrate did not clear up with empirically-chosen antibiotic treatment and persisted for several weeks without significant symptomatology, the vast majority of possible etiologies for the radiographic findings could be eliminated, raising the specter of neoplasm masquerading radiographically as pneumonia. Ultimately, the histologic diagnosis of BAC was confirmed with bronchoscopy. Combined, the histologic and radiographic data indicated a poor prognosis with widespread adenocarcinoma in consolidative form not amenable to surgical resection, but only to palliative chemo- or radiation therapy during his expected rapid decline.