False positive 131I total body scan due to an ectasia of the common carotidis

Giuffrida, Dario; Cacciaguerra, Giuseppe; Freni, V.; Ippolito, A.; Regalbuto, Concetto; Santonocito, Manuela; Belfiore, Antonino

doi:10.1007/bf03344949

Cited by 19 publications

(4 citation statements)

References 18 publications

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“…One percent of the radioiodine is excreted through the colon, and focal retention of radioiodine in the colon is another potential source for false-positive uptake in the abdomen or pelvis (Fig 9) (6,41). Stasis of radioiodine in the blood pool is a source of false-positive findings, such as stasis in the mediastinal blood pool, stasis in the intravascular blood pool in carotid ectasia (42), or stasis of extravascular blood in the endometrial canal in a patient during menstruation (Fig 10) (43).…”

Section: Radioiodine Retentionmentioning

confidence: 99%

Pictorial Review of False-Positive Results on Radioiodine Scintigrams of Patients with Differentiated Thyroid Cancer

Chudgar¹,

Shah²

2017

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Radioiodine has served an important role in the diagnostic workup and treatment of patients with differentiated thyroid cancer for more than 6 decades. The interpretation of radioiodine scintigraphic studies should be performed in conjunction with a comprehensive history, histopathologic correlation, and pertinent laboratory values, as well as correlation with available anatomic images and the findings from physical examination. A thorough understanding of the physiology and biodistribution of radioiodine is critical when interpreting radioiodine scintigraphic studies to avoid misinterpretation of physiologic and nonthyroid pathologic variants as thyroid cancer metastases. Differentiating a false-positive finding from a true metastasis on pretherapy radioiodine scintigrams is important to determine the appropriate radioiodine treatment dose. The correct interpretation of posttherapy radioiodine scintigraphic studies is also important to determine if repeat radioiodine treatment will be necessary and for the future clinical and imaging followup of the patient. A variety of different factors, such as the presence of the sodium-iodide symporter and the passive diffusion or retention of radioiodine in normal and pathologic structures, can result in false-positive results on radioiodine scintigrams. Numerous false-positive findings have been reported in the literature and are further demonstrated with the increasing availability of single photon emission computed tomography (SPECT) integrated with computed tomography (CT) as true dual-modality imaging (SPECT/CT). SPECT/CT has been documented to be of incremental value in the accurate anatomic localization and characterization of radioiodine uptake as false-positive findings, particularly in cases with discordant findings of a low serum thyroglobulin level but positive findings on radioiodine whole-body planar scintigrams. The objectives of this review are to describe the physiology and biodistribution of radioiodine and to provide examples of false-positive results on radioiodine scintigrams, with clinical and anatomic correlation, in the following categories of radioiodine uptake: functional uptake secondary to sodium-iodide symporter expression, radioiodine retention, nonthyroid neoplasms, inflammatory or infectious uptake, contamination, and other causes. RSNA, 2017.

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Section: Radioiodine Retentionmentioning

confidence: 99%

Pictorial Review of False-Positive Results on Radioiodine Scintigrams of Patients with Differentiated Thyroid Cancer

Chudgar¹,

Shah²

2017

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“…Additionally, several types of vascular malformations have been implicated in creating false positive I 131 scans through accumulation and retention of radio-labeled tracer (2)(3)(4).…”

Section: Introductionmentioning

confidence: 99%

Littoral Cell Angioma Presenting as Metastatic Thyroid Carcinoma to the Spleen

Mohan

Jones

Drake

et al. 2005

Thyroid

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Papillary thyroid carcinoma (PTC) commonly metastasizes to cervical lymph nodes. Distant metastases are unusual with the lungs most frequently involved. Well-differentiated thyroid carcinoma very rarely presents with metastases to the spleen. This is the case of a 25-year-old man with a history of PTC (1.4 cm primary; no capsular invasion and negative lymph node metastases). One year after initial surgery, recurrent disease was found in multiple neck nodes by central neck dissection. Whole body scan (WBS) following a therapeutic ablation dose of 150 mCi I(131) revealed mediastinal metastases. Computerized axial tomography (CT) of the chest one year later showed no gross mediastinal or pulmonary disease. However, multiple large splenic lesions were incidentally noted. Evaluation by ultrasound (US) showed lesions to be solid echogenic masses without remarkable Doppler characteristics to suggest vascular tumors. US-guided percutaneous fine-needle aspiration biopsy (FNAB) of one lesion was nondiagnostic. After withdrawal from Levothyroxine, serum TSH was >100 mU/L with a thyroglobulin of 9.4 ng/mL and negative anti-thyroglobulin antibodies. Diagnostic WBS revealed faint splenic uptake but was otherwise unremarkable. Following treatment with 192 mCi I(131), WBS demonstrated increased activity in the mediastinum as well as in the spleen suggesting mediastinal and splenic metastases. Contrast CT of the abdomen showed multiple low-attenuated heterogeneously enhancing splenic masses, normal liver and no intra-abdominal lymphadenopathy. The largest mass (4.5 x 3.5 cm) was exophytic and in close proximity to the splenic capsule. Despite the serum thyroglobulin of only 9.4 ng/mL, the finding of I(131) accumulation within solid splenic masses led to a preoperative diagnosis of thyroid carcinoma metastases. To establish the diagnosis and to remove the risk for splenic rupture, a laparoscopic splenectomy was performed. Histopathologic analysis showed large littoral cell angiomas (LCA). False-positive radioiodine scintigraphy in the setting of PTC involving a vertebral hemangioma has been reported. To our knowledge, this is the first case that describes multiple angiomas mimicking metastatic thyroid carcinoma to the spleen. In one-third of all cases reported, LCA co-exists with various visceral organ cancers or malignant lymphoma. This is the first report of an association between LCA and thyroid carcinoma.

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“…In lower mediastinal region, retention of gastric juice in herniated stomach or gastric volvulus can lead to false-positive I-131 scanning results. [ 9 10 11 ] Therefore, recognition of potential false-positive iodine-131 scans especially in the lower mediastinal region is critical to avoid additional costly investigations and unnecessary exposure to repeated therapeutic doses of radioactive iodine.…”

Section: Discussionmentioning

confidence: 99%

Hiatal hernia uptake of iodine-131 mimicking mediastinal metastasis of papillary thyroid carcinoma

Haghighatafshar

Khajehrahimi

2015

Indian J Nucl Med

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There are a few case reports of hiatal hernia demonstrating thoracic uptake on I-131 scintigraphy. In this case, high thyroglobulin levels in combination with misinterpretation of I-131 uptake in the mediastinum, leaded to mismanagement of the patient. Here we present a case of focal I-131 uptake within a hiatal hernia initially mimicking an isolated mediastinal metastasis. There are many potential causes of false-positive I-131 scan result. In this case, adjunctive chest computed tomography and gastroesophageal barium study helped to elucidate the true nature of this I-131 uptake. False-positive findings may be caused by a wide variety of nonthyroidal carcinomas, which can concentrate radioiodine or from skin contamination. Several organs, such as the gastric, salivary glands, renal cyst, pericardial effusion, and ovarian can accumulate I-131. It should be borne in mind as a potential source of false-positive whole-body I-131 imaging.

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False positive 131I total body scan due to an ectasia of the common carotidis

Cited by 19 publications

References 18 publications

Pictorial Review of False-Positive Results on Radioiodine Scintigrams of Patients with Differentiated Thyroid Cancer

Pictorial Review of False-Positive Results on Radioiodine Scintigrams of Patients with Differentiated Thyroid Cancer

Littoral Cell Angioma Presenting as Metastatic Thyroid Carcinoma to the Spleen

Hiatal hernia uptake of iodine-131 mimicking mediastinal metastasis of papillary thyroid carcinoma

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