A 40-year-old Chinese woman presented to the hospital with cough and a history of recurrent rash on the skin of the wrist and knee that disappeared spontaneously. As the rash tended to resolve spontaneously, she did not pay attention to it. A CT scan revealed the presence of diffuse ground glass opacity. Her personal and family history did not reveal anything remarkable, and reviews of systems were otherwise unremarkable. Physical examination revealed normal vital signs, no fever, clear lung fields on both sides, and no palpable lymphadenopathy. The results of routine lab investigations, including complete blood count and biochemistry, were normal. The tumor markers that were measured included CEA, NSE, CA125, CA199, and AFP, were in the normal range. HIV testing was negative. The result of the purified protein derivative (PPD) skin test (5 IU) was negative. Blood gas analysis showed that the pH was 7.432; PaO2, 77.1 mm Hg; PaCO2, 38.8 mm Hg; AaDO2, 26.6 mm Hg. A pulmonary function test showed that the VC was 87% predicted; the FEV1/FVC was 100% of the predicted value; and the DLCO was 86% of the predicted value. Lung HRCT showed diffuse fine nodular lesions, ground glass opacity, and minor lymphadenopathy (Fig. 1a and b).
Flexible bronchoscopy and transbronchial biopsy of the lung parenchyma and bronchoalveolar lavage (BAL) were performed. The endoscopic findings did not reveal any endobronchial lesions. Microbiological culture of the bronchial secretion showed no evidence of bacterium, fungus or mycobacterium growth. BAL fluid showed turbid liquid. The pathology report indicated the presence of epithelioid granulomas with no caseous necrosis. The result of the acid-fast bacillus test was negative.
The pathologist could not confirm the diagnosis of intrathoracic sarcoidosis due to the small size of the tissue biopsied using the flexible bronchoscope and lack of clinicoradiologic evidence. Differential diagnoses, including tuberculosis, mold infection, tumor, and other granulomatous diseases, could not be completely excluded. Therefore, thoracoscopy was performed in order to obtain a relatively large tissue mass and histologically confirm the potential disease. Right lateral thoracoscopy was performed, along with wedge resection of the right lower lobe. Intraoperative examination of the resected tissue by the pathologist revealed the presence of epithelioid granulomas. Additional pathologic examination was performed, and numerous epithelioid cell granulomas were also found in all the resected lung fields (Fig. 2).
There was no evidence of tuberculosis, mold infection, tumor, or other granulomatous diseases. Based on the histological findings, the diagnosis was pulmonary sarcoidosis. The patient was discharged 7 days after the operation. As the patient reverted back to her general state of health, 40 mg/d of prednisone was administrated orally, and it was recommended that the corticosteroid therapy be continued for 1.5 years with tapering of the dose. HRCT was performed after 6 months; the corticosteroid therapy resulted in significant ablation of the ground glass opacity in the lung (Fig. 3a and b).