A newly identified RET proto-oncogene polymorphism is found in a high number of endocrine tumor patients.

Multiple RET proto-oncogene transcripts, due to genomic variations and alternate splicing, have been described. To investigate endocrine tumor tissue characteristic RET proto-oncogene expression, we performed quantitative RT-PCR, Northern blot and Southern blot analyses of benign and malignant endocrine-derived tissues. We newly describe RET proto-oncogene expression in carcinoid-, gastrinoma- and insulinoma-derived tissue samples. In addition, the presence of a 3'-terminally truncated RET proto-oncogene mRNA variant in benign and malignant thyroid neoplasias, as well as in a pheochromocytoma, an ovarian carcinoma and a medullary thyroid carcinoma, is demonstrated. Southern blot analysis revealed no evidence of gross RET proto-oncogene rearrangements or deletions. As the underlying cause for a bi-allelic TaqI restriction fragment length polymorphism (RFLP), a C (allele 1)/T (allele 2) transition within intron 19, was characterized. This polymorphism is close to a recently described polyadenylation site and lies within a binding site for the nucleic acid binding protein Pbx-1. Screening of healthy subjects and of patients suffering from various endocrine malignancies revealed exclusively allele 1 homozygous and allele 1/allele 2 heterozygous genotypes. Heterozygous genotypes were found in a significantly higher percentage in samples derived from endocrine tumor patients when compared with those from healthy control subjects. Homozygosity for allele 2 was found exclusively in somatic DNA derived from endocrine tumors with high malignant potential. Analysis of DNA derived from varying regions within individual anaplastic thyroid carcinomas revealed an allele 1/allele 2 switch of the RFLP banding pattern, indicating loss of heterozygosity at the RET proto-oncogene locus. In conclusion, our data demonstrate presence of a 5'-terminal RET proto-oncogene transcript in endocrine tissues and reveal a bi-allelic RET proto-oncogene polymorphism. A heterozygous genotype for this polymorphism is found in a considerable number of endocrine tumor patients.

Positron emission tomography imaging of adrenal masses: (18)F-fluorodeoxyglucose and the 11beta-hydroxylase tracer (11)C-metomidate.

PURPOSE: (11)C-metomidate (MTO), a marker of 11beta-hydroxylase, has been suggested as a novel positron emission tomography (PET) tracer for adrenocortical imaging. Up to now, experience with this very new tracer is limited. The aims of this study were (1) to evaluate this novel tracer, (2) to point out possible advantages in comparison with( 18)F-fluorodeoxyglucose (FDG) and (3) to investigate in vivo the expression of 11beta-hydroxylase in patients with primary aldosteronism. METHODS: Sixteen patients with adrenal masses were investigated using both MTO and FDG PET imaging. All patients except one were operated on. Five patients had non-functioning adrenal masses, while 11 had functioning tumours(Cushing's syndrome, n=4; Conn's syndrome, n=5; phaeochromocytoma, n=2). Thirteen patients had benign disease, whereas in three cases the adrenal mass was malignant (adrenocortical cancer, n=1; malignant phaeochromocytoma, n=1; adrenal metastasis of renal cancer, n=1). RESULTS: MTO imaging clearly distinguished cortical from non-cortical adrenal masses (median standardised uptake values of 18.6 and 1.9, respectively, p<0.01). MTO uptake was slightly lower in patients with Cushing's syndrome than in those with Conn's syndrome, but the difference did not reach statistical significance. The expression of 11beta-hydroxylase was not suppressed in the contralateral gland of patients with Conn's syndrome, whereas in Cushing's syndrome this was clearly the case. The single patient with adrenocortical carcinoma had MTO uptake in the lower range. CONCLUSION: MTO could not definitely distinguish between benign and malignant disease. FDG PET, however, identified clearly all three study patients with malignant adrenal lesions. We conclude: (1) MTO is an excellent imaging tool to distinguish adrenocortical and non-cortical lesions; (2) the in vivo expression of 11beta-hydroxylase is lower in Cushing's syndrome than in Conn's syndrome, and there is no suppression of the contralateral gland in primary aldosteronism; (3) for the purpose of discriminating between benign and malignant lesions, FDG is the tracer of choice.

Long-term follow up of a "sporadic" unilateral pheochromocytoma revealing multiple endocrine neoplasia MEN2A-2 in an elderly woman.

A unilateral, apparently sporadic pheochromocytoma was removed from the right adrenal of a 73-yr-old Caucasian woman. At the time of surgery, germline DNA from the patient was not available. However, a continuous cell line (KNA) established from the tumor showed a heterozygous sequence variant TGC (cysteine) to TGG (tryptophan) in exon 10, codon 611 of the RET proto-oncogene. Subsequent genetic testing of the patient and her offspring revealed the same base-change in herself, one daughter, one son, and the only grandson, confirming hereditary disease classified as MEN2A-2. Clinical follow up of the patient revealed elevated serum calcitonin after 6 yr. Thyroidectomy was performed and revealed a small medullary thyroid carcinoma. The patient's children thus far show no evidence of MEN2, but C-cell hyperplasia has been diagnosed in the grandson. Our serendipitous finding of a MEN2A-2 mutation in a patient with initial diagnosis of late onset, unilateral, "sporadic" pheochromocytoma would argue for routine mutation screening of even elderly patients presenting with a pheochromocytoma.

Thyroid ultrasound versus antithyroid peroxidase antibody determination: a cohort study of four hundred fifty-one subjects.

Autoimmune thyroiditis is mirrored by a hypoechoic ultrasound pattern. We determined diagnostic precision of thyroid sonography compared to that of anti-thyroid peroxidase antibody (TPOAb) concentration. Ambulatory patients with unknown thyroid status (n = 451; 407 female, ages 44 +/- 16 years; 45 male, ages 50 +/- 14 years) excluding those with suspected hyperthyroidism or on drugs known to cause hypothyroidism were recruited consecutively. Subjects were recruited from a specialized thyroid outpatient unit with higher frequencies of thyroid disorders than in the general population. Before determination of thyroid function and TPOAb concentration thyroid volume (normal values: women < 12 mL, men < 14 mL) and echogenicity (grade 1 = normal: similar to submandibular gland, hyperechoic to neck muscles; grade 2: hypoechoic to submandibular gland, hyperechoic to neck muscles, grade 3: iso-/hypoechoic to neck muscles) were determined. Positive predictive value of grade 3 pattern for detection of autoimmune thyroiditis was 94% (with overt hypothyroidism) and 96% (with any degree of hypothyroidism), that of grade 2 or 3 85% and 87%, respectively. Negative predictive value of grade 1 pattern for detection of euthyroid TPOAb negative subjects was 91%. Goiter was present in 31% and 21% of TPOAb postive and negative subjects, respectively, while 11% and 15% had an atrophic thyroid gland (p = not significant [n.s.]). Given a high intraobserver and interobserver agreement abnormal thyroid ultrasound patterns were highly indicative of autoimmune thyroiditis and allowed the detection of thyroid dysfunction with 96% probability.

Multiple endocrine neoplasia type 1 (MEN1) in Austria.

Multiple endocrine neoplasia type 1 (MEN1) is a rare cancer predisposition syndrome. It results from the autosomal dominant inheritance of inactivating germ-line mutations of the MEN1 tumor suppressor gene. Mutation carriers are prone to develop tumors, preferentially, of the parathyroid and anterior pituitary glands as well as the enteropancreatic endocrine tissues. Because such tumors also occur without the MEN1 context, we have set up a molecular genetic screening program in Austria to discriminate between heritable and non-heritable tumor forms. Following the recognition of a MEN1-specific germ-line mutation in a tumor patient, we extend the screening to all first-degree relatives. To date, we have studied 42 individuals by sequencing the coding exons 2 to 10 of the MEN1 gene. A germ-line mutation was discovered in four of seven families suspected, clinically, to have MEN1, and in 3 of 22 (13.6%) patients with a presumed sporadic endocrine tumor. The respective mutations were also detected in three first-degree relatives of whom only one 6-year-old boy was asymptomatic at the time of investigation. The possibility to clearly discriminate between genetically predisposed and non-predisposed individuals has a significant impact on the diagnosis and clinical management of both patients and their relatives. Both symptomatic and asymptomatic mutation carriers can be closely monitored, thereby allowing early recognition and treatment of developing tumors. Non-affected relatives, on the other hand, do not require further controls. Finally, this approach also provides the information necessary for reliable genetic counseling.

Multiple endocrine neoplasia 1--current recommendations for diagnosis and treatment.

BACKGROUND: The principally affected glands in the MEN 1 syndrome (parathyroids, pancreas, pituitary and adrenal glands) are often diffusely or multi-centrically involved, making different therapeutic approaches necessary. METHODS: In a retrospective analysis of 10 patients with genetically proven (n = 7) or clinically suspected (n = 3) MEN 1 syndrome, recommendations for diagnosis, timing of interventions and surgical procedures are reviewed. RESULTS: All patients had primary hyperparathyroidism (PHPT). An extended bilateral exploration localized 4 or more enlarged glands in 6 patients and subtotal parathyroidectomy (SPTX) was performed. In 4 patients, only one (n = 2) or two (n = 2) enlarged glands were removed. Two patients were reoperated for persistent PHPT and one patient developed recurrent PHPT. In 3 out of 6 patients, neuroendocrine pancreatic tumors were the first manifestation. 2 patients had solitary, one patient multiple benign and one patient multiple malignant insulinomas. Tumors were removed by enucleation, distal pancreatic resection or a combination of both. Out of the 2 patients with gastrinomas, one underwent partial pancreatoduodenectomy and the other has refused operation up to now. During follow-up, no persistence or recurrence of hormone excess was diagnosed. Three patients had non-functioning bilateral lesions of the adrenal glands, and one of these additionally had a small, clinically insignificant pheochromocytoma. Adrenalectomy was performed during pancreatic surgery in 2 patients, and endoscopically in one patient. Pituitary tumors were treated in 3 patients. CONCLUSION: A high index of clinical suspicion, biochemical screening and menin gene testing, according to current guidelines, is mandatory for early diagnosis of MEN 1. In PHPT with multiglandular involvement and neuroendocrine pancreatic tumors, meticulous surgery can achieve a long-term cure in the majority of patients, with low morbidity.

Screening for medullary thyroid carcinoma: experience with different immunoassays for human calcitonin.

Calcitonin measurements in patients with nodular thyroid disease are helpful for early diagnosis and therapy of medullary thyroid carcinoma. We compared three commercial calcitonin assays routinely used: "CIS" (France), "Medgenix" (Belgium) and "Nichols-Advantage" (USA). In addition, we evaluated a two-step modification of the Medgenix-test and an enzyme immunoassay from Sangui (Japan). Method comparison studies revealed deviations from linear relationships between all routine assays. While histograms of CIS and Nichols results were similar at low concentrations with their highest frequency below 1 pg/ml, Medgenix showed a broad peak around 3 pg/ml. Correlation coefficients were 0.69 (CIS versus Medgenix) and 0.91 (CIS versus Nichols). In thyroidectomized patients, calcitonin was not detectable with CIS and Nichols, but the Medgenix test, which was more susceptible to interference, measured about 6 pg/ml. The immunoassay of Sangui showed insufficient analytical sensitivity. About 70-80% of calcitonin levels initially > 10 pg/ml were reproduced in the basal levels of the subsequent pentagastrin test. Average ratios (stimulated/basal level) were slightly higher for CIS and Nichols than for Medgenix. Prediction of a pathological stimulation from basal calcitonin was insufficient with CIS and Medgenix assays. If a calcitonin concentration of > 100 pg/ml (CIS) is considered as an indication for surgery, equivalent values are 71 pg/ml for Medgenix, and 96 pg/ml for Nichols. Using these criteria, about one third of patients who underwent pentagastrin stimulation showed pathological reactions. Reliable and sensitive calcitonin assays used for the screening of sporadic medullary thyroid carcinomas in patients pre-selected by nodular goiter are important for health and economic reasons, because they enable early therapy.

Recommendations for reporting C cell pathology of the thyroid.

BACKGROUND: Calcitonin screening programs have proved to be effective in early detection of medullary thyroid carcinoma, not only in patients with known risk factors for the development of hereditary tumors. Thus, more thyroidectomies, based on an abnormal pentagastrin test, can be expected. Here we give summarizing recommendations for reporting C cell pathology. METHODS: All patients underwent total thyroidectomy and were tested for germ-line mutations in the RET-Protooncogene. The entire surgical specimens were blocked and C-cell disorders were assessed using conventional histology and immunohistochemistry. RESULTS: Among 110 patients with an abnormal pentagastrin test, 60 (55%) had medullary thyroid carcinoma (T1 34% [n = 37], T2 14% [n = 16], T4 6% [n = 7]), and 50 (45%) had C cell hyperplasia only. C cell hyperplasia accompanying medullary thyroid carcinoma was found in 13 of 15 familial and in 28 of 45 sporadic patients. All C cell changes were found in the upper two thirds of the thyroid lobes and 83% of the medullary thyroid carcinomas could be identified with frozen sections. CONCLUSION: 1. Abnormal pentagastrin stimulation is always associated with either medullary thyroid carcinoma or C cell hyperplasia. 2. Blocking of the entire upper two thirds of the thyroid lobes is essential for reliable detection of C cell hyperplasia and small medullary thyroid carcinomas. 3. Most medullary thyroid carcinomas can be detected with intraoperative frozen sections. 4. The presence of C cell hyperplasia should always be reported; however its usefulness for indicating familial risk is limited and its role as a preneoplastic condition in patients without RET-protooncogene mutations remains to be elucidated.

Can dynamic gadolinium-enhanced magnetic resonance imaging with chemical shift studies predict the status of adrenal masses?

Endoscopic adrenalectomy represents the new gold standard in the surgical treatment of benign adrenal lesions up to 6 cm. In some cases lesions larger than 10 cm have been removed laparoscopically to offer the patient the advantages of the minimally invasive technique. The larger the diameter of an adrenal lesion, the greater the probability of malignancy. In a prospective study 130 consecutive patients (88 women, 42 men; mean age 47.8 years) with 137 adrenal lesions earmarked for surgery underwent preoperative gadolinium-enhanced magnetic resonance imaging (MRI) with chemical shift studies (CSS). The aim of this study was to predict the status (benign, borderline, malignant) of adrenal lesions by MRI irrespective of tumor size. There were 14 patients with malignant tumors, 3 had borderline tumors (epithelial tumors with high malignant potential), and the remaining 120 had benign adrenal lesions. Five malignant lesions (36%) had a diameter < 6 cm. MRI correctly predicted 11 of 14 malignant tumors (1 malignant pheochromocytoma and 2 adrenocortical carcinomas had false-negative results), 117 of 120 benign lesions, and 2 of 3 borderline lesions. All but two malignant tumors were operated on using open surgery; 82 (68%) of 120 benign adrenal lesions were treated using the transperitoneal laparoscopic approach. Tumor size alone is not suitable for predicting the status of adrenal lesions. Dynamic gadolinium-enhanced MRI with CSS can predict the status of at least 95% of adrenal lesions. Tumors> 6 cm classified as benign by preoperative MRI may be removed laparoscopically by endocrine surgeons experienced in endoscopic adrenalectomy.

Lymphocytic Hypophysitis Presenting as a Pituitary Tumor in a 63-Year-Old Man.

This report describes a case of lymphocytic hypophysitis in a 63-year-old man who presented with symptoms of a pituitary mass lesion associated with hypothyroidism and hypogonadism. Postoperative endocrinologicaI testing demonstrated gonadotropic, thyrotropic, and corticotropic hypopituitarism, and the patient was commenced on replacement therapy with hydrocortisone and levothyroxine. Histological examination of the pituitary tissue obtained by transsphenoidal surgery revealed lymphocytic hypophysitis without evidence of a pituitary adenoma. The vast majority of patients with lymphocytic hypophysitis are women particularly during pregnancy and the puerperium. Until recently only four men were reported in the literature. The pathogenesis of lymphocytic hypophysitis is uncertain but autoimmune mechanisms are possibly involved.