Nabothian cyst associated with high false-positive incidence of iodine-131 uptake in whole-body scans after treatment for differentiated thyroid cancer

Abstract

ObjectiveThis study aimed to analyze the focal uptake of iodine-131 (131I) in the upper pelvis superior to the urinary bladder on whole-body images of patients who underwent this treatment after thyroidectomy for differentiated thyroid cancer.MethodsBetween June 2012 and March 2013, 205 patients (72 men and 133 women, with an average age of 47.9±11.7 years) who underwent 131I radioactive treatment after thyroid cancer surgery were analyzed retrospectively. Pathological findings confirmed papillary thyroid carcinoma. A whole-body scan was acquired 5 days after 100–120 mCi sodium iodide was administered orally to the patients. Single-photon emission computed tomography/computed tomography (SPECT/CT) scanning was carried out to locate the lesion; this showed abnormal intense activity in the upper pelvis superior to the urinary bladder, which was further evaluated by ultrasonography.ResultsUsing 131I-SPECT scanning, five (3.76%) female patients were shown to have abnormal focal radioactivity in the lower abdomen. Subsequent SPECT/CT examination showed that the radioactivity was located in the cervix in four of the five patients and in the sigmoid colon in one patient. Transvaginal ultrasonography was performed in the former four patients, which revealed several echo-free regions in the cervix. These findings are consistent with the diagnosis of a nabothian cyst. Three of these patients were administered a second course of radioiodine therapy. Radioactive uptake was still visible at the same sites on whole-body imaging.ConclusionNabothian cyst should be considered in cases in which abnormal uptake in the upper pelvis superior to the urinary bladder is detected on 131I whole-body scans after differentiated thyroid cancer resection.

Nabothian cyst content: A potential pitfall for the diagnosis of invasive cancer on Pap test cytology

“…Reported complications of Nabothian cysts are hematometra, abnormal uterine bleeding, especially in the case of giant cysts, obstruction of labor passage, and rectal compression. In addition, false‐positive uptake of iodine‐131 in the uterus during whole body scans has been reported . In practice, superficially located Nabothian cysts can be broken by the spatula during smear taking, the mucoid content may stick to the brush and be smeared onto slides in conventional cytology or dissolved in the preserving solution for LBC preparations.…”

Radioiodine uptake in A Renal CYST in A Patient with Papillary Thyroid Carcinoma

“…However, tracer uptake has also been reported less commonly in nonthyroidal tissues, including thymus and breast, in areas of inflammation, and in cases of spina bifida, ovarian teratomas, and cysts, raising suspicion of possible metastasis (7)(8)(9)(10)(11)(12)(13). Multiple theories to explain this phenomenon of tracer uptake have been suggested, with the earliest being a possible connection between the cyst and the renal pelvicalyceal system.…”

Causes of False-Positive Radioactive Iodine Uptake in Patients with Differentiated Thyroid Cancer

“…Examples include cystic and pouch-like structures such as nasolacrimal sac cyst [37], esophageal diverticulum [38][39][40], epiphrenic diverticulum [41], pleuropericardial cyst [42], bronchogenic cyst [43,44], thymic cyst (Fig. 4) [45,46], breast cyst [47], Meckel's diverticulum [48], appendix [49], pelvocalyceal diverticulum [50,51], hepatic cyst [52][53][54], renal cyst [55][56][57][58], retroperitoneal cyst [59 • ], ovarian cyst [60,61], nabothian cyst [62], sebaceous cyst [63,64], and epithelial cyst [65]. Arterial dilation leading to stasis of blood flow has also been shown to have false-positive RAI retention [66,67].…”