Technetium- 99m-Methoxyi sobutyli sonitrile in Localization of Ectopic Parathyroid

LluIs Bernà , Assumpta Caixà s, Joan Piera, Guitlem Gómez, Xavier MatIas-Guiu, Montserrat Estorch, Manel Puig and Ignasi Carrió Departments ofNuclear Medicine, Endocrinology, and Pathology, Hospital de Sant Pau, Barcelona, Spain

nally, a planar @“Tc-MIBIscintigraphy was performed, showing a Preoperativelocalizationof ectopic parathyroidlesionsis crucial for well-delineated mediastinal hot-spot (Fig. 1). During surgery, a the correct treatment of patients with primary hyperparathyroldism. 660-mg parathyroidadenoma (Fig. 2) within the residual thymus Invasiveand noninvasiveprocedures, including selective venogra phy, ultrasound, CT and MRI provide limited sensitivity in the was found. After surgery, the patient's blood calcium levels have detection of ectopic lesions. We report three patients in whom been within the normal range for 2 yr of follow-up. @‘@‘Tc-MIBIscmntigraphyaccurately detected ectopic parathyroid Patient 2 and was instrumental in the cure for these patients. A 59-yr-old woman was admitted to the hospital because of a Technetium-99m-MIBIscintigraphyprovidesa simple and accurate 6-yr history of repeated episodes of nephrolithiasis. During the last noninvasivetest for the detection of ectopic parathyroidadenomas. 3 yr. she also reported pain and weight lost of 20 kg. Key Words primary ; ectopic parathyroid ad Laboratory tests showed hypercalcemia, hypophosphatemia, PTH enomas;technetium-99m-MIBI 22 14 pg/mt (n = 10—65)and alkaline phosphatase 2 149 U/liter J Nuci Med 1996;3763I-.633 (n = 81—263).Radiographs showed subperiosteat bone resorption and sclerosis of the vertebral bodies. Abdominal echography Singleadenomaisthemostfrequentetiologyofprimaryshowed bilateral nephrotitiasis while neck ultrasonography dem hyperparathyroidism. Surgical treatment of hyperparathyroid onstrated the presence of muttinodutar goiter without parathyroid ism is successful in 95% of patients undergoing initial neck abnormalities. A cervico-thoracic CT showed the multinodular exploration (1 ). Failure to find the parathyroidal lesion may be goiter and a hypodense image in the inferior portion of the left related to ectopia and anatomic variations in the location of the lobule that could correspond to a parathyroidal lesion. A tumor. Preoperative lesion localization, with a sensitive and planar @“@Tc-MIBIscintigraphy of the neck and thorax showed a specific imaging technique, can help in achieving better surgical mediastinal lesion (Fig. 3). A subtotal thyroidectomy was then results in those cases of ectopia or anatomic variation. Several performed and three apparently normal parathyroid glands were noninvasive procedures, such as ultrasonography, CT, MRI and identified, while the inferior left gland was not found. Surgery 2olTlfl9mTc scanning, have been tried for this purpose. In revealed that the hypodense lesion seen on CT was due to addition, invasive procedures such as selective venography, multinodutar goiter and did not correspond to a parathyroid intra-arterial digital angiography and needle aspiration com adenoma. At the same time, sternotomy was performed and a bined with high-resolution ultrasonography have been tested. mediastinat adenomatous lesion was removed. Pathology revealed None ofthese procedures provided enough diagnostic reliability a parathyroid adenoma of 2470 mg (Fig. 4). Laboratory tests to be considered the first elective procedure in the preoperative normalized after surgery. evaluation of these patients. Patient 3 A few years ago, Coakley et al. (2) introduced the use of A 48-yr-old woman was considered to have primary hyperpara 99mTcMIBI as a new agent for parathyroid imaging, and other thyroidism after a history of recurrent nephrolithiasis, hypercalce groups have subsequently confirmed its usefulness (3,4). This mia and increased PTH levels. During surgical exploration of the technique may be helpful in the preoperative management of neck, four apparently normal parathyroidal glands were identified ectopic adenomas. We present three patients in whom 99mTc@ and confirmed after pathological examination of small biopsy MIBI accurately detected ectopic parathyroid ad specimens. In addition, most of the thymic remnant was removed enomas and significantly contributed to their cure.

CASE REPORTS Patient I A 42-yr-old woman was diagnosed with primary hyperparathy roidism after 15 yr of recurrent nephrolithiasis. Neck exploration was performed on the patient and three apparently normal para thyroid glands were partially removed. The left inferior was not found and the left hemithyroid and upper thymus were removed. Histologic studies of all samples did not disclose abnormal parathyroid tissue. Due to persistent hypercalcemia, cervicothoracic MRI and CT, and selective venography were performed, failing to localize the ectopic parathyroid tissue. Fi

Received Mar. 15, 1995; revision accepted Jul. 29, 1995. FIGURE1.Technetium-99m-MIBIscintigraphyof Patient1. On the delayed For correspondence or reprints contact: Uuis Berna, MD, Unit, image(right)thereisincreasedfocaluptakeinthemediastinumcorrespond Hospital de Sait Pau, Pare Claret 167, 08025 Barcelona, Sp@n. ingto a parathyro@adenomaof 660mg.

LOCALIZATION OF ECTOPIC PARATHYROID ADENOMA •Bernà et at. 631 ‘@

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FiGURE4. Grossappearance ofthe parathyroidadenomaof Patient2.

Since Coakley et al. (2) introduced the use of 99mTcMIBI as a new agent for parathyroid imaging, several groups have shown its utility (3,4). We present three patients in whom @°@Tc-MIBIscintigraphy was accurate in depicting ectopic FiGURE2. Microscopk@appearance of the parathyrokiadenoma of Patient parathyroid adenomas. Patients 1 and 3 had unsuccessful initial 1.Thereisapredominantpopulationofchiefcells,intermingledwithvatiable amountsof oxyphilandtransitionaloxyphilcells. ; CT failed to diagnose the parathyroid lesion in Patients 1 and 2. In Patient 1, MRI and selective venography and analysis of the specimen did not reveal histologic abnormali failed to identify the parathyroid adenoma, and only in Patient ties. Due to persistence of hyperparathyroidism, an MRI study and 3 did MRI depict the ectopic parathyroid lesion. In Patients 1 a 9@Tc-MIBI scintigraphy (Fig. 5) were performed. Both studies and 2, 9@°Tc-MIBIscintigraphy was the only method that showed a mediastinat lesion located next to left pulmonary hilum. correctly identified the lesion responsible for primary hyper With findings of MIBI as the guide, thoracotomy was performed parathyroidism; in Patient 3, MRI findings were concordant and a parathyroid adenoma of 950 mg was removed (Fig. 6). with the scintigraphic image. Calcium levels decreased to normal values after surgery. MIBI uptake has been reported in different types of thyroid carcinoma, osteosarcoma, breast cancer, lymphoma, broncho DISCUSSION genic carcinoma, , undifferentiated mes For years, a classical consensus among surgeons has been enchymal tumors, carcinoid tumor and in ACTH-producing that localization techniques in patients with primary hyperpara tumors (8,9). In these different types of tumors, the biological thyroidism should not be performed unless the initial surgery uptake mechanism of 99mTc..MIBI is not well known (8,9). proved unsuccessful. Localization an9 removal of a single Some studies suggest that 99mTc..MIBI uptake may be related to abnormal parathyroid gland is usually possible without any the mitochondrial content of a particular tissue, with higher particular preoperative imaging technique, as demonstrated by avidity in those having larger numbers ofthem (10). This would cure rates up to 95% in the hands ofexperimented surgeons (1). be the case for parathyroid adenomas, since these lesions In addition, a consensus also seems to exist for patients with usually show a large number of this organelle (11 ). Further postoperative recurrent or persistent hyperparathyroidism that more, it has been reported that 99mTc@MIBIis selectively and imaging studies are required before additional surgery is per more avidly taken up by parathyroid adenomas than by the formed (5). Ultrasonography is at its best in detecting adenomas thyroid tissue (3,4). Interestingly, the washout from parathyroid around the lower pole of the thyroid, but it is not efficient for adenoma is slower than that from surrounding tissues, resulting visualizing ectopic adenomatous glands in either the posterior in a higher target-to-background ratio (3,4). Taillefer et al. (4) or superior . Computed tomography has a sensi described these double-phase kinetics of 99mTc@MIBIfor para tivity around 65% in detecting parathyroid lesions in patients thyroid adenomas and showed that late image fairly detects who have already undergone surgery; MRI has a sensitivity of abnormal parathyroid tissue. In our studies, images obtained 75%, and reported sensitivities for 2olTlfl9mTc scintigraphy for 2—3hr after injection of 20 mCi 99mTc@MIBIshowed marked this group of patients range from 26% to 80% (6, 7). accumulation in Patients 1 and 2 but onty faint uptake in Patient 3 in the mediastinum that corresponded to parathyroid adeno mas. The scintigram was extremely useful in the management and treatment decision of these patients.

FIGURE5. Leftlateralplanarviewof Patient3. Thereis a faintfocalup FIGURE3. Earlyand delayed @‘Tc-MlBlscintigraphyof Patient 2. In takeabovetheheartcorresponding creased focal uptake in the mediastinumcorrespondingto a parathyroid to a parathyroidadenomaof 950 adenomaof 2470 mg. mg.

632 THEJOURNALOFNUCLEARMEDICINE•Vol. 37 •No. 4 •April 1996 @ @, @, I

@ ‘@: :@‘.: @• @: @‘- ...@.. REFERENCES

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Disseminated Bone Marrow Metastases of Insular Thyroid Carcinoma Detected by Radioiodine Whole-Body Scintigraphy

Vittoria Rufini, Massimo Salvatori, Ida Saletnich, Stefano Luzi, Guido Fadda, Brahm Shapiro and Luigi Troncone Departments ofNuclear Medicine, Radiology, Human Pathology and Histology, Sacred Heart Catholic University, Rome, Italy; and Division ofNuclear Medicine, Department oflnternal Medicine, University ofMichigan Medical Center, Ann Arbor, Michigan

whole-body scan for metastases in differentiated thyroid carci We present 1311scintigraphic findings in a patient with insular noma being approximately 75% (1—6). carcinoma of the thyroid showing diffuseabnormal uptakethrough Uptake of -@II has also been demonstrated in recurrent and out the skeleton. The scintigraph closely resembled the pattern of r31OMIBG distribution in thildren with bone marrow metastases of metastatic insular carcinoma of the thyroid, a recently recog .The extent of invofvementwas underestimatedby nized histologic entity believed to be of follicular cell origin and bone scintigraphy and radiography. Insular carcinoma of the thyroid having a characteristic histopathologic appearance, consisting inthe bone marrow was subsequentiydemonstratedby blopsy.The of nests or “insulae―of medium sized tumor cells (7,8). This patient was treated with 242 mCi 1311given in two courses, which tumor demonstrates an aggressive clinical course with distant led to severemyelosuppressionand died as a result of progresshie metastases developing in many cases (9). disease and severepancytopenia 10 mo after initialtherapy. We present a case with unusual scintigraphic finding of Key Words insular thyroid carcinoma; bone marrow metastases; intense, diffuse 13II accumulation throughout the skeleton in a iodine-131 patient with insular carcinoma of the thyroid. The images J Nuci Med 1996;37633-636 resembled the scintigraphic pattern of MIBG distribution in patients with diffuse bone marrow infiltration by neuroblastoma (10). Bonemarrowinvolvementby insularcarcinomaof the \vhole-body13‘Iscintigraphyisthemethodofchoiceforthyroid was subsequently confirmed by iliac crest biopsy. postoperative evaluation of differentiated thyroid carcinoma for the detection of metastatic lesions, the positive rate of 1311 CASE REPORT A 61-yr-old woman presented in April 1993 with a fixed nodule ReceivedFeb.24,1995;revisionacceptedJul.5,1995. in the right thyroid lobe. For several years she suffered from diffuse For correspondence or reprints contact: VIttOIia Rufini, MD, Institute of Nudear Medidrie,SacredHeartCathdcUnh,ersity,PoliclinicoA.Gernelli,La@oi@Gemelli,8 bone pain, which had been interpreted as being due to osteoporosis Rome00168,italy. and which had been treated with calcium and . A 13‘I

MARROW META5TASES IN •Rufini et at. 633