INTRODUCTION: Thyroid nodularity is an extremely common condition, and in the era of advanced imaging modalities, thyroid nodules are being increasingly reported. Currently, US-FNAB is considered the procedure of choice for sampling the majority of thyroid nodules. In general, US-FNAB is a high yield office based procedure performed with or without local anesthesia. It is a safe procedure that was determined to decrease the rate of surgical thyroidectomies and consequently, the overall medical cost by approximately 25 percent. In opposition, sampling of substernal thyroid nodules (STN) is more challenging. In many cases, substernal thyroid nodules are not amenable to US-FNAB, and other diagnostic modalities become fundamental. Among many, mediastinoscopy and surgical excision are the most invasive alternatives. Our ambition was to use EBUS-TBNA to sample substernal thyroid nodule (1).
CASE PRESENTATION: A 72 year old gentlemen with significant past medical history of chronic obstructive pulmonary disease presented to the hospital for 2 days history of worsening shortness of breath. The patient denied any other complaints. His physical examination was unremarkable with no palpable thyroid and no neck masses. He had no evidence of stridor. Initial laboratory data including thyrotropin-stimulating hormone, was within normal range. The patient underwent a chest computed tomography (CT) of the chest with intravenous (IV) contrast to exclude pulmonary embolism. The chest CT was negative for pulmonary embolism, but showed a substernal goiter with a 2.2 cm STN in proximity with the trachea. There were no signs of airway compression. We offered the patient an outpatient EBUS-TBNA procedure to sample his thyroid nodule. The procedure was done under conscious sedation. The BF-UC169F-OL8 scope by Olympus was used. The thyroid nodule was easily identified with endobronchial ultrasonography and four transbronchial needle aspirates were performed (NA-201SX-4022 needle). The procedure was performed in about 20 minutes without complications. The patient tolerated the EBUS-TBNA very well and was discharged home 2 hours after his procedure. The cytology of the thyroid nodule was consistent with a colloid thyroid adenoma.
DISCUSSION: Since its introduction in 1996, EBUS-TBNA is becoming widely available throughout the United States. Currently, it is the procedure of choice for staging lung cancer and the initial procedure for evaluating other mediastinal pathologies like sarcoidosis. EBUS-TBNA is an outpatient procedure, performed under conscious sedation. It is a safe procedure, and carries a low complication rate when performed by experienced personnel. When used to stage lung cancer, EBUS-TBNA prevails a sensitivity of more than 90% and a specificity of 100 % averting the need for more invasive diagnostic procedures such as mediastinoscopy or surgical excisional biopsy. US-FNAB is currently the procedure of choice for sampling thyroid nodules. It is a harmless, office based procedure, performed by repetitively passing a 23 to 27 gauge needle through the nodule. In patients with malignant thyroid nodules, US-FNAB has an overall sensitivity of about 95 %(2). For substernal thyroid nodules however, US-FNAB is often not feasible and alternative approaches are often required depending on the suspicion of malignancy. Those approaches range from repeating imaging studies to more invasive excisional surgical biopsies. High risk STNs includes the following: male sex, family history of thyroid cancer, history of prior neck irradiation, large nodules, and other history of malignancy. EBUS-TBNA can be introduced as a new minimally invasive modality to sample STNs. It uses 21 or 22 gauge needles, and thus the sensitivity is expected to be at least as good as US-FNAB. In this report, we were able to simply and safely sample a substernal thyroid nodule using EBUS-TBNA.
CONCLUSIONS: In cases where US-FNAB is impossible to perform, EBUS-TBNA seems to be a reliable alternative to sample substernal thyroid nodules.
Reference #1 Chalhoub M, Harris K. The use of endobronchial ultrasonography with transbronchial needle aspiration to sample a solitary substernal thyroid nodule. Chest. 2010 Jun;137(6):1435-6.
Reference #2 La Rosa GL, Belfiore A, Giuffrida D, et al. Evaluation of the fine needle aspiration biopsy in the preoperative selection of cold thyroid nodules. Cancer. 1991 Apr 15;67(8):2137-41.
DISCLOSURE: The following authors have nothing to disclose: Kassem Harris, Michel Chalhoub, Rabih Maroun
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