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Keywords: sarcoidosis, solitary nodule, lung cancer
Abstract
Sarcoidosis shows various clinical and radiologic manifestations. Nodular sarcoidosis is an uncommon form of pulmonary sarcoidosis. Cases presenting as solid nodules are especially rare. We herein present a case of nodular sarcoidosis with a solid nodule that was suspected to be lung cancer.
A 67-year-old woman with no significant medical history was referred to our hospital for the evaluation of an abnormal shadow on the chest radiograph. The patient was a non-smoker. Physical examination revealed no acute distress. Laboratory tests showed mildly elevated C-reactive protein levels. Lung cancer tumor markers and angiotensin-converting enzyme were within the normal range. Computed tomography (CT) showed a solitary nodule with spicula in the S6 of the right lung (Figure1). Positron emission tomography (PET)/CT scan showed mild fluorodeoxyglucose uptake in the nodule and the right hilar lymph node in the delay phase (Figure2). Transbronchial biopsy of specimens demonstrated no malignant findings. We performed video-assisted thoracoscopic lung surgery for the nodule in the right lower lobe, which revealed noncaseating granulomas consistent with sarcoidosis (Figure3). Acid-fast bacilli stain and tissue cultures were negative. Histologic findings established a diagnosis of sarcoidosis.
Nodular sarcoidosis is an uncommon form of sarcoidosis prevalent in 2.4–4% of cases. 1) Most patients present with multiple lung nodules, and solitary lung nodule is a rare radiologic finding in about 18% of nodular sarcoidosis1). It is difficult to differentiate between malignancy and nodular sarcoidosis based on radiologic findings. Histological examination is necessary to establish an accurate diagnosis.