|Year : 2015 | Volume
| Issue : 3 | Page : 292-293
Single-photon emission computed tomography/computed tomography iodine-131 uptake of bronchiectasis masquerading as metastatic thryroid disease
Takman Mack, Jessica Miller, Eugene Silverman
Department of Radiology and Nuclear Medicine, Naval Medical Center San Diego, CA, USA
|Date of Web Publication||11-Jun-2015|
Department of Radiology and Nuclear Medicine, Naval Medical Center San Diego, 34800 Bob Wilson Drive, San Diego, CA 92134
Source of Support: None, Conflict of Interest: None
| Abstract|| |
We report a 37-year-old female who underwent radioiodine treatment, with subsequent scintigraphy findings suggestive of pulmonary metastatic disease. The abnormal uptake on single-photon emission computed tomography/computed tomography correlated with a focal area of the right middle lobe bronchiectasis.
Keywords: Bronchiectasis, scintigraphy, thyroid cancer
|How to cite this article:|
Mack T, Miller J, Silverman E. Single-photon emission computed tomography/computed tomography iodine-131 uptake of bronchiectasis masquerading as metastatic thryroid disease. Indian J Nucl Med 2015;30:292-3
|How to cite this URL:|
Mack T, Miller J, Silverman E. Single-photon emission computed tomography/computed tomography iodine-131 uptake of bronchiectasis masquerading as metastatic thryroid disease. Indian J Nucl Med [serial online] 2015 [cited 2020 Sep 22];30:292-3. Available from: http://www.ijnm.in/text.asp?2015/30/3/292/158555
A 37-year-old female status post total thyroidectomy for multifocal papillary thyroid cancer was subjected to radioiodine-131 treatment. The largest tumor measured was 1.6 cm in the left thyroid lobe and 3/8 positive regional lymph nodes at the time of surgery. The patient had been on a low iodine diet for 2 weeks prior to this examination (September 2011). She was clinically hypothyroid, with a thyroid stimulating hormone being 82.1 μIU/ml prior to radioiodine administration. Anterior and posterior whole body iodine-131 (I-131) planar scintigrams were obtained 8 days postadministration of 105.9 mCi of I-131. Trace activity was detected in the neck. A focal region of activity was also noted in the right lung base suspicious for pulmonary metastasis [Figure 1].
|Figure 1: Anterior and posterior whole body iodine-131 (I-131) planar scintigrams obtained 8 days postadministration of 105.9 mCi of I-131 showing residual thyroid issue and uptake in lung region|
Click here to view
Single-photon emission computed tomography/computed tomography (SPECT/CT) performed subsequently for further evaluation localized the radioactive I-131 uptake to a focal area of bronchiectasis in the right middle lobe [Figure 2]a-c], well demonstrated on chest CT [Figure 2]d]. No metastatic pulmonary mass was appreciated. The patient was further evaluated in pulmonology clinic and underwent bronchiolar lavage. The bronchial washings were sent for acid fast bacilli culture, which returned positive for mycobacterium avium complex. Repeat whole body I-131 scan and SPECT/CT was again performed in July 2014 to look for papillary thyroid cancer recurrence. The patient's mycobacterial infection had progressed to involve the lingula, with a new area of bronchiectasis seen on CT [Figure 2]e] that demonstrated corresponding activity on SPECT/CT [Figure 2]f].
|Figure 2: Single-photon emission computed tomography/computed tomography (SPECT/CT) localized tracer activity to a focal area of bronchiectasis in the right middle lobe (a-c), well demonstrated on chest CT (d). No metastatic pulmonary mass was appreciated. Follow-up iodine-131 SPECT/CT showing progression of infection with a new area of bronchiectasis seen on CT (e) that demonstrated corresponding activity on SPECT/CT (f)|
Click here to view
This case demonstrates an important pitfall in the interpretation of post thyroidectomy scintigraphy. I-131 uptake has been reported in various infectious and inflammatory processes, but infrequently with bronchiectasis, particularly with SPECT/CT confirmation. ,,,,,,,, False positive uptake is often artifactual in etiology, and usually related to urinary or salivary artifacts.  Radioiodine uptake in well differentiated metastatic thyroid cancer depends on sodium-iodide symporter (NIS) by tumor tissue. Pitfalls in the interpretation of radioiodine uptake can result from the expression of NIS by normal tissues, concentration of radioiodine in intravascular spaces, gastrointestinal/genitourinary excretion, hepatic metabolism, and physiologic secretions.  SPECT/CT helps to minimize false positive interpretation by localizing the areas of radioactivity to anatomic structures and provides more precise localization of iodine uptake.  In this case, radioiodine uptake in the right middle lobe was localized to a site of bronchiectasis on SPECT/CT, avoiding a misdiagnosis of metastatic thyroid carcinoma.
| References|| |
Bakheet SM, Hammami MM, Powe J. Radioiodine bronchogram in acute respiratory tract infection. Clin Nucl Med 1997;22:308-9.
Echenique RL, Kasi L, Haynie TP, Glenn HJ, Samaan NA, Hill CS. Critical evaluation of serum thyroglobulin levels and I-131 scans in post-therapy patients with differentiated thyroid carcinoma: Concise communication. J Nucl Med 1982;23:235-40.
Gargya A, Chua E. Focal bronchiectasis causing abnormal pulmonary radioiodine uptake in a patient with well-differentiated papillary thyroid carcinoma. Case Rep Endocrinol 2012;2012:452758.
Bakheet S, Hammami MM. Spurious lung metastases on radioiodine thyroid and whole body imaging. Clin Nucl Med 1993;18:307-12.
Haubold-Reuter BG, Landolt U, von Schulthess GK. Bronchogenic carcinoma mimicking metastatic thyroid carcinoma. J Nucl Med 1993;34:809-11.
Höschl R, Choy DH, Gandevia B. Iodine-131 uptake in inflammatory lung disease: A potential pitfall in treatment of thyroid carcinoma. J Nucl Med 1988;29:701-6.
Jong I, Taubman K, Schlicht S. Bronchiectasis simulating pulmonary metastases on iodine-131 scintigraphy in well-differentiated thyroid carcinoma. Clin Nucl Med 2005;30:688-9.
Mitchell G, Pratt BE, Vini L, McCready VR, Harmer CL. False positive 131I whole body scans in thyroid cancer. Br J Radiol 2000;73:627-35.
Song HC, Heo YJ, Kim SM, Bom HS. Iodine-131 uptake in focal bronchiectasis mimicking metastatic thyroid cancer. Clin Nucl Med 2003;28:351-2.
Oh JR, Ahn BC. False-positive uptake on radioiodine whole-body scintigraphy: Physiologic and pathologic variants unrelated to thyroid cancer. Am J Nucl Med Mol Imaging 2012;2:362-85.
Glazer DI, Brown RK, Wong KK, Savas H, Gross MD, Avram AM. SPECT/CT evaluation of unusual physiologic radioiodine biodistributions: Pearls and pitfalls in image interpretation. Radiographics 2013;33:397-418.
[Figure 1], [Figure 2]