False-Positive 131I Uptake in a Benign Bone Lesion on Post-therapy Scan

Yazıcı, Bülent; Oral, Aylin; Eraslan, Cenk; Argın, Mehmet; Ömür, Özgür

doi:10.1097/rlu.0000000000000922

Cited by 6 publications

(5 citation statements)

References 8 publications

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“…Focal I-131 uptake of one case was located to the clavicle. This patient has been reported as a case-report earlier, in whom the focal I-131 uptake corresponded to a hypodense area in the left clavicle on CT images ( 4 ). An MRI revealed that the finding belonged to a benign lesion, a simple bone cyst.…”

Section: Resultsmentioning

confidence: 53%

“…Radioiodine enters cysts by passive diffusion and is trapped in the cyst ( 8 ). In this paper, a case with I-131 accumulation due to a benign bone cyst in the clavicle is also included, who has been previously reported ( 4 ).…”

Section: Discussionmentioning

confidence: 99%

“…Post-therapeutic I-131 whole body scan (WBS) is used for restaging while diagnostic I-131 WBS is used for the follow-up of DTC patients. Despite its high specificity and sensitivity, false-positive I-131 uptake could be seen on I-131 WBS ( 4 , 5 , 6 , 7 , 8 , 9 , 10 ). Functional (residual or metastatic) thyroid tissue is not the only tissue that accumulates radioiodine, but also salivary glands, liver, breasts and thymus could accumulate radioiodine.…”

Section: Introductionmentioning

confidence: 99%

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Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

Oral¹,

Yazıcı²,

Eraslan³

et al. 2018

Mirt

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Objective:Radioiodine is the most specific radionuclide for differentiated thyroid carcinoma (DTC) imaging. Despite its high specificity and sensitivity, false-positive I-131 uptake could be seen on whole body scan (WBS) that may lead to misdiagnosis and unnecessary radioiodine treatment. In this study, we aimed to present the I-131 WBS and concomitant single photon emission computed tomography/computed tomography (SPECT/CT) images of unexpected false-positive radioiodine uptake along with the patients’ clinical outcomes and the contribution of SPECT/CT imaging.Methods:I-131 WBSs of 1507 patients with DTC were retrospectively reviewed, and anticipated I-131 uptakes (like in breasts or thymus) were excluded from the study. The unexpected false-positive I-131 uptakes with concomitant SPECT/CT imaging were included in the study.Results:Twenty-one patients had 23 unexpected I-131 uptakes on WBS and concomitant SPECT/CT imaging. The vast majority (87%) of these cases were seen on post-therapeutic I-131 WBS. Most of the false-positive I-131 uptakes could be explained by SPECT/CT and radiologic findings, and were secondary to non-thyroid conditions (bronchiectasis, lung infection, subcutaneous injection into gluteal fatty tissue, aortic calcification, benign bone cyst, vertebral hemangioma, recent non-thyroid surgical procedure site, rotator cuff injury, mature cystic teratoma and ovarian follicle cyst). However, the possible reasons of 9 false-positive I-131 uptakes could not be explained by radiologic findings.Conclusion:We suggest that false-positive I-131 uptake and its underlying mechanisms (inflammation, trapping, increased perfusion, etc.) must be kept in mind in patients with thyroid cancer and unexpected findings must be considered together with serum thyroglobulin levels, SPECT/CT and radiologic findings in order to avoid misdiagnosis and unnecessary radioiodine treatment.

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Section: Resultsmentioning

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

Oral¹,

Yazıcı²,

Eraslan³

et al. 2018

Mirt

Self Cite

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“…There are many reported cases of false-positive radioiodine uptake in tissues other than ovary, such as bone tissue [ 8 ], hepatic hydatid cyst [ 9 ] and parapelvic renal cyst [ 10 ].…”

Section: Discussionmentioning

confidence: 99%

False-positive radioiodine accumulation in a huge pelvic mass after thyroidectomy for papillary carcinoma, a case report from Syria

Almohamad

Ahmad

et al. 2018

Journal of Surgical Case Reports

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Iodine has always been connected to thyroid gland, and the fact that thyroid tissue traps, organificates and stores iodine more than other tissues is well known, hence the use of radioiodine as a diagnostic and therapeutic tool for thyroid disorders. However, false-positive cases do occur. We present a case of a 34-year-old patient who underwent total thyroidectomy for papillary carcinoma. Results of follow up TSH, thyroglobulin and thyroglobulin antibody tests after surgery lead to two rounds of radioactive iodine. After that, a radioiodine whole-body scan showed high uptake in the pelvis above bladder. Computed tomography scan showed a pelvic heterogeneous mass with some calcifications. Surgical removal and subsequent pathology confirmed the absence of metastasis. The final pathological diagnosis was serous cystadenoma, endometriosis cyst and leiomyoma. As the real cause behind false-positive iodine uptake by these tissues has yet to be determined, careful assessment should be considered in any suspicious case.

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“…Informed consent of the patient was obtained for all procedures. Many false-positive findings in I-131 scans due to physiological variants, inflammation or some non-thyroidal neoplasms have been reported (4,5,6,7,8). As a result, the following interesting/ rare situations were seen in combination in this case: false-positive I-131 uptakes at wedge-resection site and soft tissues, false-negative I-131 for FDGavid lymph metastasis, and detection of metastases after 12 years of disease-free follow-up that emphasizes the importance of long term follow-up.…”

mentioning

confidence: 99%

False-positive I-131 Uptakes at Pulmonary Wedge-resection Site and Soft Tissue Lateral to the Femoral Heads in a Patient with Papillary Thyroid Carcinoma

Yazıcı¹,

Oral²,

Alcicek³

et al. 2019

Mirt

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A hyper-metabolic pulmonary nodule was detected on 18 F-FDG PET/CT in a 65-year-old woman who had been followed up for 12 years without any complaints following treatment for papillary thyroid cancer (PTC). Wedge resection was performed to the pulmonary nodule and the pathologic examination revealed PTC metastasis. On the post-therapeutic I-131 scan after radioiodine treatment, focal I-131 uptake was detected at the site of pulmonary wedge resection. At first, this finding was thought to be related to the residual lesion but diagnostic CT demonstrated only focal traction bronchiectasis at that region. In addition, a false-positive I-131 uptake was also detected at the soft tissue just lateral to the femoral heads probably due to inflammation.

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False-Positive 131I Uptake in a Benign Bone Lesion on Post-therapy Scan

Cited by 6 publications

References 8 publications

Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

False-positive radioiodine accumulation in a huge pelvic mass after thyroidectomy for papillary carcinoma, a case report from Syria

False-positive I-131 Uptakes at Pulmonary Wedge-resection Site and Soft Tissue Lateral to the Femoral Heads in a Patient with Papillary Thyroid Carcinoma

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