Pulmonary sarcoidosis masquerading as metastatic breast cancer: a case report.

Pulmonary lesions on imaging are presumed to be metastatic lesions in patients with breast cancer. Here, we report an interesting case of a 63-year-old lady with breast carcinoma showing pulmonary lesions on imaging suggestive of pulmonary metastases. Detailed evaluation of pulmonary lesions confirmed the presence of co-existing pulmonary sarcoidosis. Modern diagnostic methods like 18-flurodeoxyglucose positron emission tomography (18-FDG PET) are unable to clearly differentiate metastatic disease from granulomatous diseases like sarcoidosis. Thus, histological confirmation is needed for accurate staging and determining response to treatment and rarely, in non-responders, detecting any co-existing disease. This case emphasizes the need for detailed histopathological examination of lymph nodes in patients with non-responsive disease or recurrent disease despite adequate chemotherapy.