Sarcoid Like Reaction Confounding the Diagnosis of Pulmonary Adenocarcinoma

Abstract

Sarcoidosis and other forms of co-existing granulomatous inflammation have been previously reported to occur along with bronchogenic carcinoma although rare. In addition, sarcoidosis has been reported as an independent risk factor for development of lung cancer. The histological findings of granulomatous inflammation can be misleading in patients with lung nodules and especially with a high pretest probability of lung cancer. We report a case of middle age Caucasian female with smoking history and obstructive lung disease who presented with multiple spiculated pulmonary nodules in both upper lobes. Pretest probability of lung cancer was high in this patient because of smoking history, location (upper lobe), appearance (spiculation) and abnormal Positron Emission Tomography (PET) scan. Initial needle biopsy by interventional radiologist revealed non-caseating granulomatous inflammation without any malignant cells leading to diagnosis of sarcoidosis. But patient underwent surgical lung biopsy because of no response to steroids that revealed the diagnosis of adenocarcinoma. Surgical lung biopsies also revealed coexisting granulomatous inflammation in the vicinity of the malignancy changes. It is difficult to establish whether the sarcoid finding in this case is an immunogenic reaction to malignancy or a precursor for malignancy. Sarcoid like reaction can rarely be seen in bronchogenic carcinoma misleading the diagnosis at times.