Somatostatin receptor PET beyond the neuroendocrine tumors of the gastrointestinal tract - the review of literature

BACKGROUND

PET of the somatostatine receptors (SSR) is a well-established functional imaging modality in the dia-gnosis of the neuroendocrine tumours (NET) of the gastro-entero-pancreatic origin (GEP). However, it can have a major impact also in other clinical entities.

PURPOSE

To present a literature review focusing on the effectivity of SSR PET in the dia-gnosis beyond GEP NET.

CONCLUSION

SSR PET provides an accurate dia-gnosis of pulmonary NET, pheochromocytoma and paraganglioma, it may have an important impact on their treatment and clinical management. It allows a detailed estimation of the extent of meningeoma, contributes to precise target volumes for radiotherapy delineation and is sensitive in its residuum or recurrence detection. It can be a valuable method in the syndromes of multiple endocrine neoplasia and in the localization of the source of the ectopic Cushing syndrome. It can be used in the medullary thyroid cancer. An important role of SSR PET lies in the planning and monitoring of the peptide-receptor radionuclide therapy embraced in the theranostic concept.

Association between neuroendocrine tumors biomarkers and primary tumor site and disease type based on total 68Ga-DOTATATE-Avid tumor volume measurements

OBJECTIVE

To determine the association between neuroendocrine tumor (NET) biomarker levels and the extent of disease as assessed by ⁶⁸Ga DOTATATE PET/CT imaging.

DESIGN

A retrospective analysis of a prospective database of patients with NETs.

METHODS

Fasting plasma chromogranin A (CgA), neuron-specific enolase (NSE), gastrin, glucagon, vasoactive intestinal peptide (VIP) and pancreatic polypeptide (PP), and 24-h urinary 5-hydroxyindoleacetic acid (5-HIAA) levels were measured. Correlation between biomarkers and total ⁶⁸Ga-DOTATATE-avid tumor volume (TV) was analyzed.

RESULTS

The analysis included 232 patients. In patients with pancreatic NETs (n = 112), ⁶⁸Ga-DOTATATE TV correlated with CgA (r = 0.6, P = 0.001, Spearman). In patients with multiple endocrine neoplasia type 1 (n = 39), ⁶⁸Ga-DOTATATE TV correlated with glucagon (r = 0.5, P = 0.01) and PP levels (r = 0.5, P = 0.049). In patients with von Hippel-Lindau (n = 24), plasma VIP (r = 0.5, P = 0.02) and PP levels (r = 0.7, P < 0.001) correlated with ⁶⁸Ga-DOTATATE TV. In patients with small intestine NET (SINET, n = 74), ⁶⁸Ga-DOTATATE TV correlated with CgA (r = 0.5, P = 0.02) and 5-HIAA levels (r = 0.7, P < 0.001), with 5-HIAA ≥8.1 mg/24 h associated with metastatic disease with high positive (81.8%) and negative (85.7%) predictive values (P = 0.001). ⁶⁸Ga-DOTATATE TV in patients with NET of unknown primary (n = 16) and those with NET of other primary location (n = 30) correlated with 5-HIAA levels (r = 0.8, P = 0.002 and r = 0.7, P = 0.02 respectively).

CONCLUSIONS

Our data supports the use of specific NET biomarkers based on the site of the primary NET and the presence of hereditary syndrome-associated NET. High urinary 5-HIAA levels indicate the presence of metastatic disease in patients with SINET.

Accuracy of [18F]fluorodopa positron emission tomography for diagnosing and localizing focal congenital hyperinsulinism

OBJECTIVES

Focal lesions in infants with congenital hyperinsulinism (HI) represent areas of adenomatosis that express a paternally derived ATP-sensitive potassium channel mutation due to embryonic loss of heterozygosity for the maternal 11p region. This study evaluated the accuracy of 18F-fluoro-l-dihydroxyphenylalanine ([18F]DOPA) positron emission tomography (PET) scans in diagnosing focal vs. diffuse disease and identifying the location of focal lesions.

DESIGN

A total of 50 infants with HI unresponsive to medical therapy were studied. Patients were injected iv with [18F]DOPA, and PET scans were obtained for 50-60 min. Images were coregistered with abdominal computed tomography scans. PET scan interpretations were compared with histological diagnoses.

RESULTS

The diagnosis of focal or diffuse HI was correct in 44 of the 50 cases (88%). [18F]DOPA PET identified focal areas of high uptake of radiopharmaceutical in 18 of 24 patients with focal disease. The locations of these lesions matched the areas of increased [18F]DOPA uptake on the PET scans in all of the cases. PET scan correctly located five lesions that could not be visualized at surgery. The positive predictive value of [18F]DOPA in diagnosing focal adenomatosis was 100%, and the negative predictive value was 81%.

CONCLUSIONS

[18F]DOPA PET scans correctly diagnosed 75% of focal cases and were 100% accurate in identifying the location of the lesion. These results suggest that [18F]DOPA PET imaging provides a useful guide to surgical resection of focal adenomatosis and should be considered as a guide to surgery in all infants with congenital HI who have medically uncontrollable disease.

[Diagnostics and treatment of neuroendocrine tumors of the digestive tract in the light of the present standards]

Neuroendocrine tumors (NET) constitute 0.5% of all cancers appearing at the man and 2% of all tumors of the digestive tract. They constitute 70% of all NET i.e., of tumors coming from endocrine cells dispersed in the entire body of the man, creating diffuse endocrine system (DES). It is estimated that the incidence of gastroenteropatic neuroendocrine tumors (GEP) is about 3 cases/year/100000 inhabitants. The characteristic feature of these tumors is that they have the ability to produce, store and secrete peptic hormones and biogenic amines. These substances are evoking characteristic symptoms which let suspect the development of certain diseases by their influence on the human organism. Little percentage of tumors coming from cells of the endocrine system does not secrete characteristic substances - these are so-called tumors hormonaly non active. The purpose of the work is to pay attention to the diagnostic-therapeutic possibility associated with the progress of medical sciences which let more frequent recognizing and more effective treatment hence the improvement of prognosis of a sick patient with GEP. In the work, I will introduce characteristics of individual GEP tumors associated with peculiar signs and diagnostic and therapeutic possibilities. In the case of neuroendocrine tumor suspection the determination made of unique and nonunique markers NET should be directed. The attempt to localise changes is based on scintigraphy with using somatostatin analogues, endoscopic ultrasonography, the computer tomography, the magnetic resonance and positron emission tomography The histopathological examination carried out on the base of guidelines of the World Health Organization from 2000 which assembly anatomical, clinical- pathological and functional features of the tumor which let making conclusive diagnosis. In the case of the GEP diagnosis, the procedure by choice is surgical treatment which, however, as a result of its high level of advancement, is often nonradical and must be completed with pharmacological treatment. As a completing treatment, analogues of somatostatin, "interferon alpha", chemotherapy and radioisotope treatment based on marked analogues of the somatostatin receptor are used. The analysis of the documentationon GEP NET tumors permits to notice that the advanced knowledge of clinical symptoms accompanying certain tumors appropriate analysis of the laboratory tests, accurate using imaging diagnostics and the cooperation with a good patomorfological centre can increase our effectiveness in recognizing and curing GEP NET tumors and, what is more, it could increase survival and improve our patients' standard of living. What is even more essential is that the majority of them is reporting to us in the moment of the appearance of complications such as the obstruction of the digestive tract, the obstructive jaundice, nonunique pain complaints of the abdominal cavity. GEP NET tumors are another group of diseases requiring the interdisciplinary approach of many specialists to a patient-gastroenterologists, endocrinologists, radiologists, surgeons, specialists of nuclear medicine and chemotherapy

What is the link between nonlocalizing sestamibi scans, multigland disease, and persistent hypercalcemia? A study of 401 consecutive patients undergoing parathyroidectomy

BACKGROUND

We hypothesized that nonlocalizing sestamibi scans would correlate with multigland disease and persistent primary hyperparathyroidism.

METHODS

We reviewed records for 401 consecutive patients who underwent parathyroidectomy from 1999 to 2004. Gender, age, preoperative imaging, surgical findings, gland weight and volume, and 6-month calcium levels (Ca) were examined.

RESULTS

We identified 289 women and 112 men, 297 of whom had a preoperative sestamibi scan localized to a single gland (localized group; LG). Ninety-six percent of the LG were found to have single-gland disease, and 4% had multigland disease (MGD). In the nonlocalized group (NLG), 76% had single-gland disease and 24% MGD. Mean gland weight was greater in the LG than in the NLG (1128 mg vs 699 mg; P < .05). Mean gland volume was larger in the LG (1.34 cc vs 0.89 cc; P < .05). A localizing sestamibi scan had a positive predictive value (PPV) of 96% and a likelihood ratio of 2.29 for predicting "curative" intraoperative parathyroid hormone drop after removal of a single abnormal gland. Patients were stratified into normocalcemic (NCa) and hypercalcemic (HCa) groups based on 6-month postoperative serum calcium data (n = 328). HCa incidence at 6 months did not differ significantly between the LG (5%) and NLG (3%). A localizing scan had a PPV of 95% for normocalcemia at 6 months. A nonlocalizing scan had a PPV of 21% for HCa at 6 months.

CONCLUSIONS

Nonlocalizing sestamibi scans were more common in primary hyperparathyroidism with MGD and were associated with smaller-volume abnormal glands found at operation. Preoperative sestamibi scan-results did not predict HCa at 6 months.

Toxicity of high-activity 111In-Octreotide therapy in patients with disseminated neuroendocrine tumours

Disseminated neuroendocrine tumours are difficult to treat and are generally not responsive to radiotherapy or chemotherapy. Nuclear medicine techniques using a radiolabelled somatostatin analogue, 111In-Octreotide, have been used for the diagnosis of neuroendocrine tumours. It has been suggested that high activities of such an agent may have a therapeutic effect. The aims of this study were to assess toxicity and to determine if there had been evidence of efficacy. Eight patients with known disseminated neuroendocrine tumours were enrolled in the study; six had carcinoid tumours, one had a medullary cell carcinoma of the thyroid and one patient had a malignant gastrinoma. Between 1.3 and 4.6 GBq of 111In-Octreotide were administered to each patient for up to five administrations over 12 months. A total of 23 administrations were given. Tests of vital signs, renal, liver and endocrine function as well as haematological markers were taken before and after treatment. The treatment was well tolerated with only one patient suffering from a sensation of flushing during the infusion but no changes in vital sings. There was a transient (up to 48 h) drop in circulating lymphocytes in four patients and platelets in two patients; no supportive therapy was needed. One patient with severe renal impairment had a slight reduction in glomerular filtration rate. We conclude that high-activity 111In-Octreotide is well tolerated with low toxicity and can be considered for use in patients with disseminated neuroendocrine tumours. Further work is now being performed to assess efficacy.

Parathyroid imaging with Tc-99m sestamibi planar and SPECT scintigraphy

Technetium-99m sestamibi planar and single-photon-emission computed tomographic scintigraphy is useful in the diagnosis of parathyroid gland disease. To understand the various patterns of parathyroid disease, it is important to understand parathyroid embryology and anatomy. The spectrum of parathyroid disease demonstrated with Tc-99m sestamibi scintigraphy includes eutopic disease, ectopic disease, solitary adenoma, double or multiple adenomas, cystic adenoma, lipoadenoma, multiple endocrine neoplasia, hyperfunctioning parathyroid transplant, entities with atypical washout, and nonparathyroid entities that take up Tc-99m sestamibi. The diagnosis of parathyroid tumors with Tc-99m sestamibi scintigraphy is based on the difference in clearance rates between the thyroid and diseased parathyroid glands, and any condition that interferes with radiotracer clearance will limit the effectiveness of the study. The technique is most clearly indicated for the preoperative evaluation of recurrent or persistent hyperparathyroidism, but it is increasingly being used before the initial surgical exploration as well. Subtraction Tc-99m sestamibi and iodine-123 scintigraphy may be helpful in difficult cases. Parathyroid hyperplasia, multisite parathyroid disease, and concomitant thyroid and parathyroid disease remain potential hurdles for this scintigraphic technique, and optimal handling of these problems still relies heavily on the skill and experience of the endocrine surgeon.

[Multiple familial pheochromocytomas: sonographic demonstration of multiple adrenal, celiac and bladder localizations in a child]

Familial pheochromocytoma is an uncommon form of this neoplasia. It is characterized by an autosomal dominant inheritance and multicentric locations. It is more frequently encountered in children, but with a smaller risk of malignant transformation than in adults. The familial form may be associated with other disorders, particularly with multiple endocrine neoplasia (MEN), Von Hippel-Lindau's disease and Von Recklinghausen's disease. We report the case of a nine-year-old boy with multiple familial pheochromocytoma in whom sonography allowed to demonstrate five localizations.

[PET in clinical work. A refined instrument for imaging]

Positron emission tomography (PET) enables in vivo studies to be performed in patients to investigate the binding or metabolism of biologically/functionally active substances labelled with short-lived positron-emitting radionuclides. The procedure has been used for discriminative analysis of physiology and function, both normal and pathological. The range of clinical applications includes studies of cerebral ischaemia and heart diseases, tumor diagnosis and treatment follow-up, presurgical work-up in cases of epilepsy, and characterization and treatment follow-up in cases of dementia. The clinical uses of PET are outlined in a review of the last three years' experience at the PET centre at Uppsala University.

Tc-99m sestamibi imaging of a pancreatic VIPoma and parathyroid adenoma in a patient with multiple type I endocrine neoplasia

Technetium-99m sestamibi is known to localize in primary malignant and metastatic tumors. Specifically, brain, breast, thyroid, parathyroid, lung, and kidney tumors have been imaged. The Verner Morrison syndrome, which is caused by excessive vasoactive intestinal peptide (VIP), consists of watery diarrhea, hypokalemia, and achlorhydria. This condition is rarely associated with multiple endocrine neoplasia. The authors present a case of multiple endocrine neoplasia type I with visualization of a pancreatic VIPoma and parathyroid adenoma with Tc-99m MIBI.

Somatostatin-receptor imaging of medullary thyroid carcinoma

In-111 pentetreotide scintigraphy of 10 patients with residual or metastatic medullary thyroid carcinoma is described. Six patients had sporadic tumor and 4 had MEN IIB. Foci of increased tracer uptake were observed in 9 patients: in the thyroid bed (4 patients), the mediastinum (3 patients.), the shoulder area and left lower abdomen (1 patient), and the left upper abdomen (1 patient). The 10th patient had no abnormal uptake. CT confirmed 2 mediastinal lesions and 2 out of 3 thyroid masses, but did not detect the thyroid remnants or the lesions in the shoulder area and abdomen. Lung lesions < or = 1 cm in diameter and ill-defined liver foci (2 patients) were seen on CT, but not on scintigraphy. Small liver metastases not demonstrated on CT or on scintigraphy were identified at surgery in a MEN IIB patient. Elevated urinary epinephrine was found in 2 out of 4 MEN IIB patients. In one, tracer uptake in the left adrenal corresponded to a mass on CT, to pathological uptake of MIBG and DMSA, and to a tumor removed at surgery. The second patient had peritoneal spread of malignant pheochromocytoma (at surgery), but negative CT and only a single focus in the left lower abdomen on scintigraphy. Somatostatin-receptor imaging is useful for the detection of residual and recurrent medullary thyroid carcinoma, and may identify pheochromocytoma in MEN IIB patients.

Sonography of the thyroid and parathyroid

Ultrasound is a primary imaging tool for thyroid and parathyroid localization. Classic thyroid and parathyroid tumors are easily distinguished by their sonographic appearance and location, but variations are common and complicate the distinction. Thus, biopsy under ultrasound guidance provides proof of the nature of the lesion. When parathyroid localization is problematic with ultrasound, magnetic resonance imaging is an excellent alternative.

Ultrasonography of the pancreas in patients with multiple endocrine neoplasia type I

Fifty-seven patients with the multiple endocrine neoplasia type I (MEN-1) syndrome underwent sonographic examinations, and focal pancreatic lesions were demonstrated in 18 (33%). Size ranged from 5 to 65 mm in diameter, and multiple lesions were seen in five patients. Eight patients with pancreatic lesions less than 20 mm have been followed over a period of 1 to 6 years. Of these eight patients, only one had a lesion that increased in size. Ultrasonography was able to detect asymptomatic pancreatic tumors in a higher proportion of MEN-1 patients than previously. Sonography is a useful method of detecting islet cell tumors greater than 5 mm in diameter and is able to follow up these lesions to assess increase in lesion size and number.

[Re-evaluation of ultrasonographic localization in primary hyperparathyroidism (report of 55 cases)]

In 1983-1991, 55 cases of primary hyperparathyroidism confirmed by pathology and surgery were screened by ultrasonography. Its frequency was 3.5 or 7.5 MHz. The ultrasonographic results showed as follows. The appearance rate of the foci in the normal position of the parathyroid was 95%, including adenoma and hyperplasia; its size of pathology was bigger than that determined by US; the sensitivity of US was 55.3%, specificity 96.2%, accuracy 81.8%, positive predictive value 81.5%, and negative predictive value 86.5%. The results improving its level of ultrasonographic diagnosis were proved as follows. (1) knowing the anatomy of parathyroids, and preventing from false positive and false negative; (2) differentiating from primary and secondary hyperparathyroidism; (3) grasping the features of multiple endocrine neoplasia; (4) careful and repeated examination was key to early and correct diagnosis.

[The assessment of clinical usefulness of 131I-MIBG scintigraphy for localization of tumors of sympathetic and adrenomedullary origin--a report of multicenter phase III clinical trials]

A phase III clinical study of 131I-metaiodobenzylguanidine (131I-MIBG) was performed in 66 patients with tumors of sympathetic and adrenomedullary origin, including 32 patients with suspected pheochromocytoma, 25 with suspected neuroblastoma, 7 pre- or postoperative medullary carcinoma of the thyroid and each with carcinoid and suspected Sipple's syndrome. A total of 150 sites which were confirmed for presence (72 sites) or absence (78 sites) of tumors were examined on 131I-MIBG scintigrams. True positive ratio of the scintigraphy was 84.7% (61/72) and true negative ratio was 94.9% (74/78). Positive scintigraphy was obtained in 86.5% (32/37) of pheochromocytoma, 78.6% (22/28) of neuroblastoma and 100% (6/6) of medullary carcinoma of the thyroid. Accumulation of 131I-MIBG was seen in 16.8% of normal adrenal glands. Neither adverse reactions nor abnormal laboratory findings were noted in relation to 131I-MIBG injections. Our study indicates that 131I-MIBG is a safe and clinically useful radiotracers for the visualization and localization of tumors of sympathetic and adrenomedullary origin.

111In-octreotide scintigraphy in oncology

Various tumors of neuroendocrine origin that have amine precursor uptake and decarboxylation (APUD) characteristics can be visualized in vivo after intravenous (IV) injection of the somatostatin analogue, [123I-Tyr3]-octreotide. However, the relatively short effective half-life of this compound and the high background of radioactivity in the abdomen are drawbacks to its application. Therefore, an 111In-coupled somatostatin analogue ([111In-DTPA-D-Phe1]- octreotide) was developed. This analogue is excreted mainly via the kidneys, with 90% of the dose being present in the urine 24 hours after injection. Using 111In-octreotide scintigraphy, seven of seven gastrinomas, four of seven insulinomas, one of one glucagonomas, three of three unclassified APUDomas, and none of 18 exocrine pancreatic carcinomas were visualized. Also, 19 of 19 carcinoids, 15 of 15 glomus tumors, eight of 12 medullary thyroid carcinomas, six of six small-cell lung carcinomas, four of four growth hormone-producing and six of nine clinically nonfunctioning pituitary adenomas were visualized. Apart from APUD cell-derived tumors, 111In-octreotide scintigraphy was also successfully applied in visualizing breast cancer, lymphomas, and granulomas. In 39 of 50 patients with breast carcinoma, 10 of 11 patients with non-Hodgkin's lymphomas, three of three patients with Hodgkin's disease, and eight of eight patients with sarcoidosis, tumor sites accumulated radioactivity during octreotide scintigraphy. In a considerable number of patients with carcinoids and glomus tumors, and also in patients with granulomas and lymphomas, 111In-octreotide scintigraphy showed more tumor sites than did conventional imaging techniques. The results of imaging in vivo correlated with the somatostatin-receptor status on the tumors in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Scintigraphic study of extra-adrenal ganglioneuroma in a patient with overlap between multiple endocrine neoplasia types 1 and 2

A 27-year-old woman was diagnosed with a pituitary prolactinoma. Seven years later, when she was 34, an abdominal mass was incidentally discovered and ascribed to the right adrenal gland on the basis of evidence from ultrasonography, computed tomography, and arteriography. Adrenal scintigraphy with Se-75 selenomethylcholesterol imaged both adrenal glands, but the right gland was distorted, suggesting external compression. I-131 MIBG was not taken up by the mass. At surgery, an extra-adrenal ganglioneuroma was found and excised. This case represents an overlap between multiple endocrine neoplasia types 1 and 2. The failure of the ganglioneuroma to concentrate MIBG was likely caused by secretory inactivity of a biologically mature tumor.

Clinical and genetic features of adrenocortical lesions in multiple endocrine neoplasia type 1

In multiple endocrine neoplasia type 1 (MEN-1), benign enlargement of the adrenal cortex has been found in about one third of necropsy cases. To elucidate the clinical and genetic characteristics of the MEN-1 adrenal lesion, we have investigated 33 MEN-1 patients. Twelve individuals (37%) demonstrated adrenal enlargement, which was bilateral in 7 of them. Histopathology revealed diffuse and nodular cortical hyperplasia, adenomas, and a single case of adrenocortical carcinoma. The apparently benign adrenal enlargements were not associated with presently ascertainable biochemical disturbances in the hypothalamic-pituitary-adrenocortical axis, and they were without radiological signs of progression during follow-up. The individual developing unilateral adrenocortical carcinoma showed rapid adrenal expansion, feminization, and an abnormal urinary steroid profile after 4 yr of observation for bilateral minor adrenal enlargements. Pancreatic endocrine tumors were significantly overrepresented and present in all MEN-1 individuals with adrenal involvement. In agreement with findings in sporadic cases, the MEN-1 adrenocortical carcinoma genome showed loss of constitutional heterozygosity for alleles at 17p, 13q, 11p, and 11q. The benign adrenal lesions retained heterozygosity for the MEN-1 locus at chromosome 11 q 13. Despite its prevalence and malignant potential, the pituitary-independent adrenocortical proliferation does not appear to be a primary lesion in MEN-1, but might represent a secondary phenomenon, perhaps related to the pancreatic endocrine tumor.

Multiple endocrine neoplasia type 2 with malignant pheochromocytoma — Long term follow-up of a case by131I-meta-iodobenzylguanidine scintigraphy—

The case of a 33-year-old Japanese man, who has Multiple Endocrine Neoplasia Type 2 (MEN IIa) (Sipple's syndrome) with malignant pheochromocytoma, is reported. He had survived for twelve years since the initial diagnosis of malignant pheochromocytoma. Within this period, he had undergone 131I-meta-iodobenzylguanidine scintigraphy twice, in 1983 and 1990. This is the first case in Japan of a longterm surviving patient with malignant pheochromocytoma followed up by 131I-MIBG scintigraphy. Although he had no exacerbation of clinical symptoms or urinary catecholamine levels, second scintigraphy clearly showed an increase in the tumor size, new metastasis of the malignant pheochromocytoma and exacerbation of the medullary thyroid carcinoma. Compared with any other roentgenological device and hormonal data, 131I-MIBG scintigraphy was seen to be a good tool for evaluating the localization and the progression of tumors. 131I-MIBG scintigraphy is a useful procedure not only for initial diagnosis but also for judging progression in a case of advanced malignant pheochromocytoma.

Somatostatin receptor imaging of endocrine gastrointestinal tumors

Somatostatin receptors are present on various tumors of neuroendocrine origin. We recently developed a technique for the in vivo visualization of somatostatin receptor positive tumors, which offers a powerful alternative to tumor imaging with labeled monoclonal antibodies. Instead of injecting radiolabeled antibodies against the somatostatin receptor, we labeled a somatostatin analogue ([Tyr3]-octreotide) which is known to bind specifically to the somatostatin receptor, and injected this labeled hormone analogue in order to visualize somatostatin receptor positive tumors. We previously reported the successful visualization of the primary tumors or metastases of various endocrine gastrointestinal tumors after injection of the iodinated somatostatin analogue [123I-Tyr3]-octreotide. The primary tumors or metastases of 12 out of 13 carcinoids, 3 out of 3 gastrinomas, 2 out of 4 insulinomas, and 1 out of 1 somatostatinoma were visualized. Using 111In-coupled octreotide, we were able to visualize 19 out of 19 carcinoids, 7 out of 7 gastrinomas, 4 out of 7 insulinomas, 1 out of 1 glucagonoma, and 3 out of 3 non-functioning endocrine pancreatic tumors, but none of 18 exocrine pancreatic tumors. In a large proportion of patients with endocrine gastrointestinal tumors, previously unrecognized metastases were demonstrated. Also, the absence or presence of in vivo visualization of these tumors after the injection of radiolabeled octreotide seems to predict the ability of octreotide therapy to control symptoms caused by hormonal secretion from these tumors.

IN CONCLUSION

111In-octreotide scintigraphy is a simple and sensitive technique for localizing of the primary tumor and its metastases in the majority of patients with carcinoids or endocrine pancreatic tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

[Myocardial calcinosis in a juvenile patient with Wermer syndrome (multiple endocrine neoplasia type I)]

We describe the rare case of a 19 year-old patient with multiple endocrine neoplasia (Wermer syndrome), presenting with insulinomas as well as primary hyperparathyroidism. Echocardiography revealed evidence of calcific deposits in the interventricular septum. The latter may be explained by long-standing hypercalcemia.

MR imaging and MIBG scintigraphy of pheochromocytomas and extraadrenal functioning paragangliomas

To compare the potential of magnetic resonance (MR) imaging and scintigraphy performed with radiotracer-labeled metaiodobenzyl-guanidine (MIBG) in localization and characterization of functioning paragangliomas, the authors analyzed results of both modalities in 33 patients. Overall sensitivity for detection was 91% for MR imaging and 80% for MIBG scintigraphy. MR imaging demonstrated 100% of adrenal paragangliomas and 75% of extraadrenal paragangliomas, whereas MIBG scintigraphy revealed 75% and 88%, respectively. MIBG scintigraphy was more specific in the characterization of paragangliomas than MR imaging (100% vs 82%). However, MR imaging demonstrated nine other lesions not seen on scintigrams. On the basis of their results and other considerations, the authors believe MR imaging is the preferred initial technique when a functioning paraganglioma is suspected.

Surgical treatment of endocrine pancreatic lesions in MEN-1

The surgical treatment of endocrine pancreatic lesion in the multiple endocrine neoplasia syndrome type 1 (MEN-1) has remained a controversial issue. Histologic studies have revealed that the pancreatic lesions generally consist of numerous microadenomas, spread throughout the pancreas, together with occasional larger tumors. The patients may also harbor multiple, mainly gastrin secreting, duodenal microadenomas. A total pancreatectomy/duodenectomy should theoretically be needed for cure, but has not been recommended due to the associated mortality and morbidity, considering also the favorable prognosis of most MEN-1 patients. When pancreatic involvement in MEN-1 is biochemically diagnosed efforts should be made to localize the lesions by computed tomography, angiography and, in some patients, also transhepatic portal vein catheterization and venous sampling (PTP). Hypergastrinemia and the Zollinger-Ellison syndrome (ZES) generally constitute two-thirds of the clinically detected pancreatic lesions in MEN-1. Surgery may be undertaken in ZES-MEN-1 patients with focal lesions visualized by radiology or PTP in order to minimize the risk of malignant development in a gross tumor. Patients with insulin excess and hypoglucemia as well as the rare vipoma patient may, even in the absence of radiologically visualized tumors, be subjected to exploration, and these patients are usually found to harbor one or several gross tumors. The more frequent clinically silent, mainly PP-producing tumors should be removed when visualized by radiology. However, indications for surgery also have to emphasize an unusually malignant behavior in certain kindreds and patients may thus have to be explored when only biochemical data indicate the presence of pancreatic lesions. Pancreatic operations in MEN-1 should generally include a corpus and tail resection, together with enucleation of lesions in the pancreatic head, and in addition to that a careful duodenal exploration. Intraoperative ultrasound examination appears to be of considerable value by its ability to reveal also smaller lesions which may escape palpation.

Multiple endocrine neoplasia type IIB identified by magnetic resonance imaging

Ectopic, epinephrine-secreting pheochromocytomas are rare and difficult to diagnose. In our case, MRI was able to show the lesion, which could not be clearly identified by CT. The histologic specificity provided by T2-weighted images confirmed the biochemical diagnosis of pheochromocytoma. MRI should be considered as an alternative to CT in the diagnosis of familial pheochromocytomas.

CT scanning as an adjunct to screening for medullary carcinoma of the thyroid

CT scanning of the thyroid following oral administration of potassium iodate was performed on two sisters in whom raised calcitonin levels had been found at a pentagastrin stimulation test undertaken to screen for medullary carcinoma of the thyroid. Three histologically proven, clinically occult C-cell carcinomas measuring 2 mm or less were detected by CT scanning. This technique may be useful prior to surgery in patients in whom medullary carcinoma of the thyroid is suspected but not proven.

Preoperative localization of endocrine pancreatic tumours by intra-arterial dynamic computed tomography

Eleven patients with biochemically confirmed endocrine pancreatic tumours were examined with intra-arterial (i.a.) dynamic computed tomography (CT) and angiography preoperatively. Seven of the patients suffered from the multiple endocrine neoplasia type 1 (MEN-1) syndrome. All patients were operated upon and surgical palpation and ultrasound were the peroperative localization methods. Of the 33 tumours which were found at histopathologic analysis of the resected specimens in the 11 patients, 7 tumours in 7 patients were correctly localized by both i.a. dynamic CT and angiography. Six patients with MEN-1 syndrome had multiple tumours and this group of patients together had 28 tumours, of which 5 (18%) were localized preoperatively by both CT and angiography. I.a. dynamic CT, with the technique used by us, does not seem to improve the localization of endocrine pancreatic tumours, especially in the rare group of MEN-1 patients, as compared with angiography.

Pentavalent technetium-99m (V)-DMSA uptake in a pheochromocytoma in a patient with Sipple's syndrome

This case report describes 99mTc(V)-dimercaptosuccinic acid (DMSA) accumulation in a pheochromocytoma in a patient with Sipple's syndrome. Scintigraphy with 99mTc(V)-DMSA demonstrated uptake in medullary carcinoma of the thyroid gland (MCT). Iodine-131 metaiodobenzylguanidine (MIBG) scintigraphy showed the bilateral pheochromocytomas but did not demonstrate uptake in the MCT.

Zona fasciculata cortical adenoma and adrenal medullary hyperplasia in MEN II patient: unique concurrent presentation

I-131 MIBG for the localization of pheochromocytoma is a highly specific agent. In this case report, an apparent false-positive finding attributed to the presence of three zona fasciculata cortical adenomata was ultimately deduced to be due to the presence of adrenal medullary hyperplasia in this MEN patient.

Methodology and dosimetry in adrenal medullary imaging with iodine-131 MIBG

Iodine-131 MIBG scans were performed in 59 patients in order to localize intra- or extra-adrenal pheochromocytomas (pheos), or to visualize hyperplastic adrenal medulla. Images were obtained from the pelvis to the base of the skull on Days 1, 4, and 7 after tracer injection. The 15 patients with histopathologic confirmation of adrenal medullary disease had positive scans. In three of these, the pheos were visible only on images obtained on Day 7. One scan was false negative. After excluding patients with a predisposition to adrenal medullary disease, nine subjects (28%) without verification of pheo displayed adrenal uptake of the radionuclide. Late images produce a low rate of false-negative scans; the background activity diminishes and even small pheos can be detected. In order to increase the quality of late images, 40 MBq [131I]MIBG was used instead of 20 MBq. The dosimetric considerations are discussed.

Medullary thyroid carcinoma: localization of a mediastinal metastasis with I-131 MIBG

An I-131 metaiodobenzylguanidine (MIBG) scan was performed in a patient with a familial history of multiple endocrine neoplasia (MEN) type 2 and recurrent medullary thyroid carcinoma (MTC). The scan revealed a mediastinal metastasis from her MTC and there was also an imaging pattern of bilateral adreno-medullary hyperplasia. Although the literature indicates that I-131-MIBG scanning is not sufficiently sensitive for the detection of MTC, this procedure has proven to be of value in the management of chosen patients with MEN-associated MTC.

Scintigraphic portrayal of the syndrome of multiple endocrine neoplasia type-2B

The scintigraphic appearance of the neoplasms in multiple endocrine neoplasia type 2B (MEN-2B) and the interpretations of the image patterns are described. An 18-year-old male patient with the MEN-2B syndrome underwent TI-201 imaging that showed concentrations of TI-201 in the primary medullary thyroid carcinoma (MTC) tumor and in cervical lymph node metastases. After total thyroidectomy and lymph node dissection, the TI-201 image was normal. Catecholamine levels in the blood and urine were only borderline elevated. Yet, greater than normal concentrations of I-131 metaiodobenzylguanidine (I-131 MIBG) were present in both adrenal glands. Computed tomography of the abdomen showed normal adrenal glands. These results were consistent with the diagnosis of adrenal medullary hyperplasia, a precursor of pheochromocytoma. No operation was indicated to remove the adrenal glands. Imaging with TI-201 appears to be useful in identifying sites of MTC in patients with the MEN-2B syndrome. I-131 MIBG imaging, in conjunction with computed tomography of the adrenal glands and appropriate catecholamine measurements, should be performed in patients with the MEN-2B syndrome to determine the status of the adrenal medullae, which then may be classified as normal, hyperplastic, or tumorous with pheochromocytoma.

Sipple's syndrome with liver tumors examined by iodine-131 MIBG and technetium-99m(V)-DMSA

This case report describes the localization and categorization of tumors using 99mTc(V)-dimercaptosuccinic acid and [131I]metaiodobenzylguanidine scans in a very uncommon case of medullary thyroid carcinoma associated with pheochromocytoma (Sipple's syndrome) and hepatocellular carcinoma. Technetium-99m(V)-dimercaptosuccinic acid showed accumulation only in medullary thyroid carcinoma, but [131I]metaiodobenzylguanidine scans were positive in both medullary thyroid carcinoma and pheochromocytoma. In advanced Sipple's syndrome, combined use of [99mTc(V)]dimercaptosuccinic acid and [131I]metaiodobenzylguanidine may be useful for the categorization of tumor mass lesions and planning appropriate therapy.

Thyroid uptake of MIBG in Sipple's syndrome

The use of the adrenomedullary tracer metaiodobenzylguanidine (MIBG) in the localization of medullary carcinoma of the thyroid (MCT) is based on the embryologic relationship of the APUD cell series. The authors report the results obtained in six patients with MCT: two had Sipple's syndrome and four sporadic forms of the disease. MIBG uptake by the CMT was observed in both cases of Sipple's syndrome and in only one of the other cases. Scintigraphic detection seems to depend on the clinical features, the size of the tumour and also on the part played by its secretory function. MCT would thus appear to be more frequently visualized by MIBG in cases of Sipple's syndrome than in sporadic cases. The procedure therefore seems useful in the diagnosis, follow up and even in the treatment of MCT.

Iodine-131 MIBG uptake in metastatic medullary carcinoma of the thyroid. A patient treated with somatostatin

A 47-year-old man with multiple endocrine neoplasia (MEN) type 2a syndrome in whom metaiodobenzylguanidine (MIBG) concentrated in lesions from metastatic medullary carcinoma of the thyroid is reported. A somatostatin analogue (Sandostatin SMS 201-995) alleviated the symptoms of flushing and diarrhea associated with the elevated calcitonin levels but it did not alter either the course of the disease or the MIBG images. A review of the literature is presented of the noncatecholamine secreting tumors associated with MIBG uptake. Similarities between this case and metastatic carcinoid syndrome are discussed.

Radioiodinated meta-iodobenzylguanidine uptake in medullary thyroid cancer. A French cooperative study

Fifty meta-iodobenzylguanidine (MIBG) scintiscans were performed in three groups of medullary thyroid cancer (MTC) patients. Group 1 (n = 11) included treated patients with normal calcitonin levels; Group 2 (n = 24) included patients with elevated calcitonin levels due to sporadic and isolated MTC; Group 3 (n = 15) included patients with elevated calcitonin levels due to familial MTC or multiple endocrine neoplasia Type IIA syndrome (MEN). In Group 1 three pheochromocytoma were depicted by MIBG scintiscan. In Group 2 MTC was seen in a small number of patients (3 of 24). In Group 3, besides adrenal hyperplasia and pheochromocytoma four patients, MIBG scintigraphy showed where MTC had localized and spread in almost half of patients (7 of 15). MIBG uptake occurred in patients with relatively high calcitonin level (greater than 0.6 nmol/l). These data indicate that in patients with familial MTC or MEN syndrome, MIBG scintiscan can be useful not only in detecting associated pheochromocytoma, but also in showing MTC.

Clonidine-induced suppression of plasma catecholamines in states of adrenal medulla hyperfunction

To assess adrenal medulla activity in states of hyperfunction, a single 0.3 mg oral dose of clonidine hydrochloride (Catapres) was given to twelve patients with varying evidence of familial adrenal medullary hyperplasia and pheochromocytomas from kindreds with Multiple Endocrine Neoplasia type 2 syndrome (MEN-2), seven patients with sporadic pheochromocytomas and six normal subjects. Mean arterial blood pressure and plasma norepinephrine (NE) levels were lower than baseline values 2 h after clonidine in the normal subjects. Plasma epinephrine (E) rose in one normal but fell in the remainder after clonidine administration. In sporadic pheochromocytoma patients, E fell slightly in 4 and NE fell in 3 while mean arterial blood pressure was not significantly lower than baseline values in 7 patients 2 h after clonidine. In MEN-2, mean arterial blood pressure fell and there was a variable response of plasma E and NE to clonidine, which appears to be related to the presence of detectable anatomic (CT scan) and functional (131I-mlBG scintigraphy) abnormalities of the adrenal medulla. These findings are thus compatible with the spectrum of adrenal medulla dysfunction and the presumed development of pheochromocytoma in this syndrome.