Metastatic struma ovarii: the burden of truth

A 58-year-old woman was found to have metastatic thyroid cancer in her liver. This was identified when she was investigated for upper abdominal pain and underwent biopsy of hepatic lesions. She had no palpable thyroid nodule and had a normal ultrasound of the thyroid. Previously, both ovaries had been removed because of tumors. The pathologic findings in one of the ovaries could not be recovered because the procedure was more than 40 years ago, when the patient was a teenager. By a process of elimination, a diagnosis of metastatic struma ovarii was established. Treatment of metastatic thyroid cancer from struma ovarii, including removal of the normal thyroid and administration of I-131, is presented.     

Incidental Findings of Intense Radioiodine Uptake in Struma Ovarii and Bilateral Nonlactating Breasts Simultaneously on Postablation <Superscript>131</Superscript>I SPECT/CT for Papillary Thyroid Cancer

A 52-year-old woman diagnosed with papillary thyroid carcinoma was referred for ¹³¹I therapy following total thyroidectomy. She was given 4,810 MBq (130 mCi) of ¹³¹I following 4 weeks of thyroid hormone withdrawal. A posttherapy scan showed intense, focal activity in the pelvis and intense, diffuse activity on both sides of the chest, which was localized to the right ovary and both breasts on SPECT/CT examination. She had bilateral nipple pain and a history of antidopaminergic drugs as combination medication for her rheumatoid arthritis and prokinetics during radioiodine therapy. On a ¹²³I whole-body scan 9 months later after stopping the drugs, bilateral breast uptake was not visible; however, right ovarian focal uptake was still visualized. Bilateral salpingo-oophorectomy was performed, and revealed struma ovarii with substantial internal necrosis due to radioiodine therapy. This case is interesting as two rare entities, ¹³¹I therapy-related struma ovarii and drug-related breast uptake, were simultaneously visualized.     

Functioning liver metastases on an I-131 whole-body scan: a case of malignant struma ovarii

A 46-year-old women was examined for severe constipation. Pelvic examination revealed a large pelvic mass extending to the level of the umbilicus. Computed tomography showed a large multicystic, septated mass in the pelvis and a small amount of fluid in the cul de sac. In addition, multiple ill-defined, mixed-attenuation hepatic lesions were identified. A malignant ovarian neoplasm with liver metastases was considered, so the pelvic mass was resected. Interestingly, histopathologic analysis revealed malignant struma ovarii of the follicular type. Biopsy of the liver lesions confirmed metastatic disease with similar histopathologic findings. All thyroid laboratory values were in the normal range. The patient then had a total thyroidectomy to optimize thyroid ablation therapy with I-131. This revealed a small follicular adenoma but no evidence of cancer. An I-131 whole-body scan was performed and showed uptake in multiple functioning liver metastases.     

Metastatic malignant struma ovarii. Two case reports.

Struma ovarii is an ovarian germ cell tumor consisting mainly of thyroid tissue. Five percent of struma ovarii are malignant, and of these only five percent metastasize. The rarity of this disease has resulted in difficulty in agreeing on treatment regimes and in limited imaging experience. The authors report two cases and highlight the imaging and monitoring difficulties encountered in their management. The authors conclude that I-131 has a role to play both therapeutically and in monitoring these patients, but that biochemical testing is a more reliable indicator of disease status.     

Malignant struma ovarii: Case report of an unusual ovarian tumor with CT imaging

Struma ovarii is categorised as a monodermal type of mature teratoma and consists primarily of thyroid tissue. It is an uncommon ovarian tumor, with non–specific clinical, and imaging findings. The majority of struma ovarii are benign and are typically associated with mature cystic teratomas. A small proportion of struma ovarii may undergo malignant transformation, with papillary carcinoma the most common type of malignancy. The criteria used to identify a malignant change in struma ovarii are identical to those used to evaluate the thyroid gland. Nevertheless, due to the rarity of struma ovarii, imaging diagnostic criteria, and subsequent management are not clearly defined. This case report describes a 41-year-old female patient who presented with rapid abdominal enlargement over a period of 1 month, accompanied by elevation of the tumor marker CA-125. Based on these clinically findings, ovarian cancer was suspected. The patient underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy. Histopathology results revealed a malignant struma ovarii.     

Radioiodide imaging of struma cordis

This is the first reported case in which struma cordis was demonstrated with radionuclide imaging. A 56-year-old white woman underwent surgical excision of a benign intracardiac thyroid mass (struma cordis). Subsequent radionuclide imaging with I-123 sodium iodide and Tc-99m labeled red blood cells demonstrated a normal cervical thyroid gland as well as a focus of activity in the mediastinum consistent with intracardiac thyroid.     

Struma ovarii: hyperthyroidism in a postmenopausal woman

A rare case of struma ovarii producing hyperthyroidism in a postmenopausal woman is reported. The ovarian tumor demonstrated uptake of both [99mTc]pertechnetate and 131I, allowing preoperative diagnosis of the condition. In females with unexplained hyperthyroidism and low 131I uptake by the cervical thyroid gland, imaging of the pelvis should be considered.     

Radiotherapy with iodine-131 in recurrent malignant struma ovarii

Malignant struma ovarii is a very rare disease and, therefore, there is neither common agreement on treatment regimens nor sufficient follow-up experience. We present a case of a 49-year-old woman with malignant struma ovarii of the follicular type, who received ablative radioiodine treatment after thyroidectomy and surgical removal of the primary tumour. During followup examinations an increasing thyroglobulin level was found, caused by a tumour relapse with suspected urinary bladder infiltration on CT and proven uptake of radioiodine on whole-body scanning with iodine-131. After administration of 6 GBq¹³¹I, complete tumour regression was achieved with no evidence of a new relapse during a 30-month follow-up period. Correspondingly, repeated thyroglobulin measurements were all negative. This case demonstrates the benefit of combined surgical and radioiodine treatment of malignant struma ovarii for both monitoring and therapy of relapse or metastases; thus, the same therapeutic regimen as is employed in primary differentiated thyroid carcinoma may be recommended.     

Superiority of iodine-123 compared with iodine-131 scanning for thyroid remnants in patients with differentiated thyroid cancer

PURPOSE: Iodine-123 is a pure gamma emitter and has excellent characteristics for imaging with modern scintillation cameras. The goal of this study was to compare the performance of I-123 and I-131 as imaging agents for whole-body scanning in patients with differentiated thyroid cancer undergoing ablation for thyroid remnants after initial surgery. METHODS: Fourteen patients with differentiated thyroid cancer who had undergone near-total thyroidectomy and had serum thyroid-stimulating hormone levels greater than 40 mU/I underwent diagnostic scanning 5 hours after administration of 48 to 56 MBq (1.3 to 1.5 mCi) I-123 and 48 hours after administration of 111 MBq (3 mCi) I-131. After receiving ablative I-131 therapy, they also underwent whole-body planar imaging 7 days later. The diagnostic I-123 and I-131 scans were compared with each other and with the post-therapy images by two nuclear medicine physicians and one endocrinologist. RESULTS: The diagnostic scans revealed 35 foci in the thyroid bed and neck. The I-123 images showed all 35 foci, but only 32 of the 35 foci (91 %) were seen on the I-131 scans. The findings of pre- and post-therapy scans were concordant in 11 of 13 patients, and the same general sites of uptake (left and right thyroid bed, midline) were revealed on both sets of images. In one patient, a focus seen on the diagnostic I-123 and I-131 images was not visualized on the post-therapy scan and was thought to represent possible stunning. An additional area of uptake in the lower right neck and upper mediastinum was present on the post-therapy scan of another patient, but it was not seen on diagnostic images. CONCLUSION: These results show improved quality of imaging with 50 MBq (1.5 mCi) I-123 compared with 111 MBq (3 mCi) I-131 for whole-body scanning in patients with differentiated thyroid cancer undergoing thyroid remnant ablation. I-123 imaging may prove to be the preferred procedure in such settings in patients with differentiated thyroid cancer.     

Timing and potential role of diagnostic I-123 scintigraphy in assessing radioiodine breast uptake before ablation in postpartum women with thyroid cancer: a case series

Breast accumulation of I-131 may be an undesirable effect of I-131 ablation in postpartum women being treated for differentiated thyroid cancer. The use of diagnostic I-123 scintigraphy before ablation does allow an assessment of potential postablative breast uptake in such patients. This case series of 8 patients evaluates I-123 scintigraphy in the assessment of breast uptake in postpartum women with thyroid cancer. Of these patients, 7 were studied at various times after cessation of lactation and in one patient, lactation was not initiated at all. Of the group who did not receive lactation-inhibiting medications, there was variable breast uptake demonstrated and by 6 months postcessation of lactation, some patients showed persisting breast uptake but others demonstrated no uptake. In the group treated with lactation-inhibiting medications, such as bromocriptine or cabergoline, breast uptake appears to be reduced much earlier with uptake becoming absent after as little as 3 weeks of treatment. There was barely discernible uptake in the patient in whom lactation was never initiated. I-123 scintigraphy may help guide clinicians on the appropriate timing of radioiodine ablation to help minimize concentration of I-131 in breast tissue.     

Struma ovarii simulating a teratodermoid cyst. Computed tomographic findings in one case

A case report is presented in which there were computed tomographic (CT) findings of struma ovarii (SO) simulating a teratodermoid cyst. The patient was a 73-year-old woman with a painful mass in the lower abdomen. CT revealed a large complex mass with multiple cystic and solid components. One of the cysts had fat-fluid level and minor calcification in the wall. The histological findings were struma ovarii. To our knowledge, these CT findings have not been described previously. Our case demonstrates the importance of including struma ovarii in the CT differential diagnosis of teratodermoid cysts.     

Biodistribution and dosimetry of N-isopropyl-p-[123I]iodoamphetamine in the primate

The biodistribution of N-isopropyl-p-[123I]iodoamphetamine (I-123 IMP) in the Macaca fascicularis monkey was determined at 15 min and at 1, 4, 24, and 48 hr after intravenous injection. Brain uptake was 7.8% of the injected dose at 1 hr, with little change in concentration between 15 min and 1 hr, falling thereafter. Eye uptake reached a maximum of 0.23% of injected dose at 24 hr, with activity primarily in the pigmented layers. The human absorbed radiation dose was calculated on the basis of biodistribution data. The critical organ is the eye (0.407 rad/mCi of I-123 IMP). The eye dose increased to 1.11 rad/mCi with 4% contamination from I-124 IMP and to 0.535 rad/mCi with 0.4% contamination from I-125 IMP. The absorbed dose to the liver was 0.127 rad/mCi for pure I-123 IMP and the thyroid dose was 0.120 rad/mCi, both increasing with either I-124 or I-125 contamination. While delayed eye uptake has not yet been reported in the human, care should be exercised in limiting the amount of contaminating I-124 or I-125 to the lowest practical level.     

Coexistence of a nonfunctioning thyroid nodule in Plummer's disease demonstrated by thallium-201 imaging

A patient with Plummer's disease in whom a coexisting nonfunctioning thyroid nodule was detected by TI-201 imaging is presented. I-123 imaging revealed a hot nodule corresponding to the functioning nodule and little uptake in the rest of the thyroid. In contrast, two areas of abnormalities were noted on a TI-201 image: one corresponded to the hot nodule in I-123 imaging and the other was visualized in the suppressed part of the thyroid in the same lobe. This case revealed that TI-201 imaging is clinically useful in detecting coexisting nodules in the suppressed part of the thyroid.     

MR findings of struma ovarii

This study was performed to characterize MR findings of struma ovarii.In 10 patients, T1- and fast spin echo T2-weighted MR images were obtained in the axial, coronal, and sagittal planes using 1.5 T MR units, and they were retrospectively evaluated for the site, size, components, signal intensity, and contrast enhancement.MR images showed a unilateral complex mass with a multilobulated surface and thickened septa, corresponding pathologically to thyroid follicles and the stroma. Cystic portions had variable signal intensities on T1- and T2-weighted images. The contents of cystic components showing low signal intensities both on T1- and T2-weighted images were viscid gelatinous materials (n=4). Solid portions were relatively well-enhanced.In conclusion, struma ovarii has some characteristic MR appearance of a multilobulated complex mass with thickened septa, multiple cysts of variable signal intensities, and enhancing solid components.     

Radionuclide thyroid studies: a survey of practice in the United States in 1981. Special report

A survey was conducted to determine the radiopharmaceuticals and radionuclide imaging methods used for thyroid studies in the U.S. in 1981. The final sample, made up of 299 hospitals, was taken from a random sample consisting of 10% (337) of U.S. hospitals performing nuclear medicine studies. The survey showed that over one half of thyroid scans were obtained with Tc-99m pertechnetate and over one half of uptake studies were performed with I-131. Uptake determinations accompanied 78% of scans. Only 8% of the uptake studies were performed without scans. I-123 was more commonly used on the west coast and in the northeast, and there was interest in a more readily available and less expensive supply of I-123. Thyroid studies accounted for 6.7% of all nuclear imaging procedures. Approximately 7,760,000 nuclear medicine imaging procedures were performed in the U.S. in 1981.     

Thyroid imaging agents: a comparison of I-123 and Tc-99m pertechnetate

Tc-99m pertechnetate and I-123 were used to perform thyroid scanning in 122 patients with history or clinical evidence of thyroid disease. Thyroid scans were abnormal in all patients, while thyroid palpation was abnormal in all but 19. The quality of thyroid imaging was similar with both agents in 42%, better with I-123 in 18%, and better with Tc-99m in 7%. In the remaining 33% (40 cases), there were discrepancies between Tc-99m and I-123 images. The most frequent discrepancies were "hot" or "warm" lesions on Tc-99m scans that were "cold" or normal on I-123 scans. Results from this study indicate that neither Tc-99m nor I-123 is always superior to the other as a thyroid imaging agent.     

Comparative biodistribution of iodinated amino acids in rats: selection of the optimal analog for oncologic imaging outside the brain.

3-(123)I-Iodo-alpha-methyltyrosine ((123)I-3-IMT) is used for the detection of residual and recurrent brain tumors. The application of (123)I-3-IMT for the study of extracerebral malignancies is limited by its marked and rapid renal uptake. In this study, we compared the tumor uptake, biodistribution, and specificity of 5 structurally related iodinated amino acids with those of (123)I-3-IMT. The aim was to select the optimal analog for oncologic imaging outside the brain. METHODS: We studied 3-(123)I-iodotyrosine ((123)I-3-IT), 2-(123)I-iodotyrosine ((123)I-2-IT), (123)I-iodo-azatyrosine ((123)I-IAzaT), 2-(123)I-iodophenylalanine ((123)I-2-IPhe), and 4-(123)I-iodophenylalanine ((123)I-4-IPhe). Tumor uptake and renal uptake in sarcoma-bearing rats were measured by use of in vivo dynamic imaging. The differential uptake ratio (average counts per pixel of the region of interest divided by the average counts per pixel inside the total body) and rates of tracer accumulation (K(1) values) were calculated. Results were compared with the values obtained for (123)I-3-IMT in the same rat. Tracers that demonstrated high tumor uptake were labeled with (125)I and coinjected with (18)F-FDG in rats with turpentine-induced acute inflammation. After 30 min, the rats were sacrificed and dissected. Amino acid tracer uptake in organs and tissues was measured, and the increase in uptake in the inflamed muscle was expressed relative to the increase in (18)F-FDG uptake. RESULTS: Tumor uptake and K(1) values for (123)I-2-IT and (123)I-2-IPhe were comparable to those for (123)I-3-IMT. (123)I-4-IPhe showed high tumor uptake but a reduced K(1) value because of high blood-pool activity. (123)I-3-IT and (123)I-IAzaT did not accumulate markedly in tumor tissue. Renal accumulation of (123)I-2-IT, (123)I-2-IPhe, and (123)I-4-IPhe was at least 6 times lower than that of (123)I-3-IMT. (18)F-FDG uptake was markedly increased in areas of acute inflammation (215%). The increases for (125)I-3-IMT and (125)I-4-IPhe were 35.5% and 22.2%, respectively, of the increase for (18)F-FDG. Almost no increase was found for (125)I-2-IT (3.3%) and (125)I-2-IPhe (2.8%). CONCLUSION: (123)I-2-IT and (123)I-2-IPhe are promising tracers for oncologic imaging outside the brain. (123)I-2-IT has the advantage of an established kit for radiosynthesis.     

Struma ovarii with hyperthyroidism

A case of hyperthyroid disease after total thyroidectomy is reported. An initial scintigraph with Tc-99m sodium pertechnetate confirmed the absence of uptake in the neck. The view of the pelvis revealed a rounded area of increased uptake on the left, near the sacroiliac joint (results of bone scintigraphy were negative). A wholebody scan with iodine-131 confirmed a struma ovarii that was bilateral, which occurs in 5% to 10% of patients with this condition.     

Transient thyrotoxicosis in a patient with a functioning nodule; A possible occurrence of silent thyroiditis

A 48-year-old woman with diffuse goiter presented with typical symptoms and signs of thyrotoxicosis. Thyroid scanning with I-123 revealed a localized accumulation of the radionuclide in the left lobe which corresponded to a small nodule later detected by ultrasonography, with suppression of the remaining tissues. Owing to the overall reduced radioactivity in the thyroid, she was suspected of having silent thyroiditis causing thyrotoxicosis. Meanwhile, the thyrotoxicosis subsided concurrently with an increase in radioactivity in the extranodular area that had initially been suppressed. The histology of thyroid tissues obtained at the time of operation revealed follicular adenoma or hyperplasia in the area of the localized I-123 uptake and findings similar to those in Hashimoto's thyroiditis in the remaining tissues, supporting our clinical diagnosis of silent thyroiditis together with a functioning nodule.     

I-123 whole body scanning: case report and discussion

PURPOSE: In managing differentiated thyroid carcinoma, concern over the stunning that may occur with traditional whole body imaging using I-131 has fostered an interest in using I-123 for this purpose. A case is presented as a focus for discussion of the issues, with special reference to accuracy and the effect thereon of technical factors. CASE REPORT: A 43-year-old man with papillary carcinoma of the thyroid was scanned after thyroidectomy using 10 mCi I-123. Images at 24 and 48 hours demonstrated foci including multiple regional metastases. They were less well demonstrated in images 7 days after therapeutic I-131, and negative imaging 1 year later implied therapeutic success. DISCUSSION: I-131 has the advantages of a longer half-life, facilitating delayed imaging and lower price. I-123 has the advantages of favorable gamma-ray energy and less useless radiation to thyroid tissue and the whole body. Despite its short half-life, with a sufficient amount, images at 48 hours are practical. In the case presented, there are several possible reasons why superior lesion detection occurred in diagnostic I-123 images. In any case, the outcome demonstrates that I-131 posttherapy images are not an absolute "gold standard" for accuracy. Investigations comparing I-123 with I-131 imaging have been subject to biases, including insufficient dose of I-123, lack of delayed I-123 imaging, suboptimal collimation for I-131, and the relatively high dose of I-131 in posttherapy scanning. CONCLUSIONS: The evidence, although not definitive, strongly suggests that I-123 is at least as accurate for diagnostic whole body imaging as I-131.