Neuroendocrine tumor imaging: can 18F-fluorodeoxyglucose positron emission tomography detect tumors with poor prognosis and aggressive behavior?

We evaluated the clinical value of positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) for neuroendocrine tumor (NET) detection. Sixteen patients with cytologically or histologically proved NETs were investigated. Patients were divided in two groups of eight patients each according to the clinicopathologic features related to prognosis: slow-growing NETs and aggressive NETs. Results of FDG tumor uptake as detected by PET were compared with computed tomography (CT) scans and with scans obtained with 111In-octreotide scintigraphy (n = 13). Tumor FDG uptake was increased in the primary lesion of all eight aggressive NETs; the tracer was shown also in lymph nodes, liver metastases, or both in five of six of them (83%). In four cases, additional unknown tumor sites undetected by CT scan were identified. A slight positivity was found in only one of eight cases with a slow-growing NET. The overall octreotide scintiscan sensitivity was 85%, but in the aggressive NETs it failed to detect the primary lesion in two of seven cases. Uptake of the tracer in some but not all tumor lesions in the same patient was seen by both FDG-PET and octreotide scintiscans. From our limited experience 18F-FDG PET seems to be useful for identifying NETs characterized by rapid growth or aggressive behavior. Uptake of the FDG tracer by the tumor may be related to a worse prognosis. Despite the heterogeneity of tracer uptake in the various lesions of NETs with multiple tumor sites, FDG-PET was able to detect unsuspected distant metastases, contributing to better staging of advanced disease.

Unusual association between a thyrotropin-secreting pituitary adenoma and a papillary thyroid carcinoma.

We report here an unusual case of association between thyrotropin (TSH)-secreting pituitary adenoma and papillary thyroid carcinoma in a young female patient. Serum TSH levels did not significantly change after both stimulatory (thyrotropin-releasing hormone [TRH], domperidone) and inhibitory (bromocriptine levotriiodothyronine, [LT3], levothyroxine [LT4], LT4 plus LT3) tests, while a 67% decrease of serum TSH levels was obtained after acute administration of a somatostatin analog (SMS 201-995, 100 microg s.c.). Serum alpha-subunit levels and the alpha-subunit/TSH molar ratio were clearly elevated. Magnetic resonance imaging (MRI) revealed the presence of a pituitary adenoma (1 cm in diameter). Pitfalls arising from the failure to inhibit TSH secretion in a patient thyroidectomized for papillary cancer are discussed.

Potential role of fluorine-18-deoxyglucose (FDG) positron emission tomography (PET) in the staging of primitive and recurrent medullary thyroid carcinoma.

We investigated 5 MTC patients, 3 preoperatively for staging purpose, and 2 after surgery, during the follow-up, because of the persistence of elevated serum tumoral markers. FDG PET results were compared with conventional radiologic (US, CT scan, MRI) and scintigraphic non-invasive techniques (99mTc-MIBI and 99mTc-MDP scans). In all the 3 patients preoperatively studied, PET, as well as the other imaging modalities, detected the primitive tumor and the loco-regional lymphnode metastases. Furthermore, in one case, PET was the only technique that revealed an additional localization to the lungs. One false negative result was recorded with PET, as well as with the conventional imaging, in a MTC patient with a MEN II syndrome and with some liver micrometastases, 2 to 5 mm sized, showed only at laparotomy. PET was the only method capable of early visualizing a mediastinal relapse of the tumor in one of the 2 patients studied during the follow-up. This patient was re-operated and serum calcitonin levels became undetectable. On the basis of our preliminary results on MTC, PET with FDG seems to be an accurate, non-invasive technique, for staging purpose before surgery, and, during the follow-up for visualizing tumoral spread in patients with increased serum tumoral markers.

Functional meaning of scintigraphic and echographic patterns, and of circulating anti-peroxidase antibodies in asymptomatic chronic thyroiditis.

Asymptomatic chronic thyroiditis (ACT) is a variant of the autoimmune thyroiditis characterized by the presence of circulating anti-thyroid antibodies and the absence of palpable goiter. Thyroid function can be normal but a considerable percentage of ACT patients tend to develop subclinical hypothyroidism over time and thus periodical controls of thyroid hormones and TSH levels are needed. At present, useful parameters for predicting the functional outcome of ACT patients are lacking. To investigate this aspect, we evaluated 57 consecutive ACT patients (51 females, 6 males, aged 22-56 years) by means of thyroid 99mTc-pertechnetate scintigraphy and echography, and by measuring the serum level of anti-peroxidase antibodies (TPOAbs), FT4, T3 and TSH. At first observation, 30 patients were euthyroid whereas 27 had subclinical hypothyroidism. No patient had been previously treated with thyroid hormones. Thyroid scan showed a normal pattern or a diffuse and mild irregular uptake, without differences between euthyroid and subclinical hypothyroid patients. TPOAb levels tend to be higher in patients with subclinical hypothyroidism in comparison to the euthyroid patients (5893 +/- 1423 and 3943 +/- 912 UI/mL, respectively) but the difference was not statistically significant by using Student's "t"-test. Echography showed a normal pattern in 14 patients, while a diffuse hypoechoic pattern in the other cases, mild in 12, moderate in 19 and marked in 12, was found. A significantly higher prevalence of subclinical hypothyroidism was observed in the group of patients with a moderate or marked hypoechoic pattern in comparison to the group with a normo-echoic or mild hypoechoic pattern (70.4% versus 23.0%, Fisher's exact test p = 0.00003). Furthermore, the 3 patients who developed thyroid failure during a one-year follow-up also presented a moderate or marked hypoechoic pattern. Our data suggest that the echo-pattern can be a useful predictor of thyroid failure in ACT patients and thus the echographic evaluation should be included in the diagnostic protocol of these patients.

[Primary hyperparathyroidism and peptic ulcer]. / Iperparatiroidismo primitivo ed ulcera peptica.

The prevalence of peptic ulcer disease was retrospectively analysed in 35 patients affected by primary hyperparathyroidism consecutively observed from 1977 through 1987. Eight of the examined patients (22.8%) had peptic ulcer (7 duodenal and 1 gastric ulcer), that in five cases (14%) represented the first clinical manifestation of the endocrine disease. A Zollinger-Ellison syndrome was demonstrated in three cases (8.5% of the total series, 37% of the patients with ulcer). There was no difference in calcium, gastrin and parathormone serum level between patients with and without ulcer, excluding patients with Zollinger-Ellison syndrome. These data confirm the high prevalence of peptic ulcer disease in hyperparathyroidism, but the mechanism causing this association remains to be elucidated.

Hyperthyroidism associated with primary cirrhosis. Two case reports.

Only a single case of Graves' disease has been reported so far in Primary Biliary Cirrhosis (PBC), whereas hypothyroidism is a rather common association. We report two cases of hyperthyroidism associated with PBC. A common pathogenic mechanism involving HLA II class antigens is suggested.

[Radioimmunologic determination of circulating parathyroid hormone in patients with primary and secondary hyperparathyroidism]. / Determinazione radioimmunologica del paratormone circolante in pazienti con iperparatiroidismo primitivo e secondario.

A radioimmunological evaluation was made of plasma parathormone (PTH), using an antibody against the C-terminal fraction, in 14 subjects with primary parahyperthyroidism, and in 19 anuric subjects with secondary forms on three-weekly dialysis. In all cases, values were significantly higher (p less than 0.01) than in a group of normal controls. In secondary forms, the same significance was also apparent on comparison with primary forms, probably due to an absence of renal clearance of the hormone.

[Basal prolactinemia and level after stimulation with TRH in juvenile gynecomastia]. / La prolattinemia basale e dopo stimolo con TRH nella ginecomastia giovanile.

TSH and PRL in basal conditions and after stimulus with TRH, gonadotrophin in basal conditions and after stimulus with GnRH, plasma testosterone, urinary oestrogens and peripheral thyroid hormones have been evaluated in 11 subjects with puberal gynaecomastia, 7 with post-puberal gynaecomastia and 14 normal controls. With respect to the normal controls, only patients with post-puberal gynaecomastia showed higher levels of basal PRL and after TRH stimulus. The behaviour of these patients could suggest that in subjects with post-puberal gynaecomastia there may be persistent endocrine imbalance, whereas in puberal gynaecomastia such imbalance is only transitory and is exhausted prior to the onset of mammary tumefaction.

[Cardiotoxicity induced by 5-fluorouracil. A case report]. / Cardiotossicità da 5-fluorouracile: descrizione di un caso clinico.

A case of ischemic cardiopathy which was observed after 5-fluorouracil administration for a carcinoma of the small intestine is described.