INTRODUCTION: Whole-body fluorodeoxyglucose (FDG) positron emission tomography (PET) scans can be utilized in identifying occult granulomas in patients with Sarcoidosis(1). The usual standardized uptake value (SUV) range is between 2.0 and 16.0 units(2). We present a case of a 47 year-old man with bilateral mediastinal and hilar adenopathy with an SUV score range from 12 to 24. These findings have not been previously reported in the literature.
CASE PRESENTATION: A 47 year old Caucasian man presented with a left lower lobe nodule that was discovered incidentally after an unremarkable computed tomography angiogram (CTA) of the coronary arteries for chest pain. The patient denied any pulmonary or constitutional symptoms. He was born and raised in Arizona. He had not recently traveled and had no exposure to pollutants, dust or fumes. He worked as a copier repair technician for several years. His vital signs and physical examination findings were normal. His initial CTA reveled 6.1 x 5.3 millimeter nodule in left lower lobe. A follow-up CT of the chest in six months revealed multiple new subcentimeter parenchymal nodules, bilateral hilar, mediastinal, and subcarinal lymphadenopathy. A PET scan was performed because of a concern for malignancy. The PET result was suggestive of malignancy due to the SUV range of 12 to 24 in the mediastinal lymph nodes. An endobronchial ultrasound-guided (EBUS) transbronchial needle aspirate (TBNA) of the hilar and mediastianal lymph nodes was inconclusive showing benign lymphocytes and bronchial cells and rare histiocytic aggregates suggestive of but not diagnostic for a granulomatous condition. A subsequent mediastinoscopy revealed noncaseating granuluomas of the paratracheal lymph nodes suggestive of Sarcoidosis. Stains for acid-fast bacilli (AFB) and fungi were negative. There was no evidence of malignancy. During his evaluation, the patient developed hyperpigmented macular lesions of the anterior lower extremities with bilateral ankle arthritis strongly suggestive of a diagnosis of Lofgren’s Syndrome. He was not treated with corticosteroid therapy, improved dramatically over the next few months, and had complete resolution of his CT findings within one year.
DISCUSSION: Sarcoidosis is a chronic granulomatous inflammatory disease without a clear etiology that suggests a broad differential diagnosis. When a diagnosis of malignancy is suspected in a patient with chest adenopathy and pulmonary nodules, an adequate biopsy must be obtained as Sarcoid is a diagnosis of exclusion(1). Although there are few studies examining the typical findings of Sarcoidosis on FDG PET, a detailed literature review has failed to reveal any value greater than 16 involving hilar or mediastinal adenopathy. Higher SUV values should not narrow the diagnosis toward malignancy and exclude a diagnosis of Sarcoid.
CONCLUSIONS: Sarcoidosis may present with mediastinal or hilar lymphadenopathy and SUV scores as high as 24 units on FDG-PET scan
Reference #1 Gulla, S. Basic Radiology, 2nd Edition. McGraw Hill 2011
Reference #2 Teirstein, A. Results of 188 Whole Body FDG PET Scans in 137 Patients with Sarcoidosis. Chest December 2007
DISCLOSURE: The following authors have nothing to disclose: Mehul Patel, Numan Rashid, Damien Compa
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