Parathyroid carcinoma. A concise review.

Parathyroid carcinoma is a very rare malignancy and the least common among endocrine malignat tumors. Its etiology is still unclear and some hypotheses have been suggested: previous external radiation to the neck, pregression from benign to malignant lesion, familial hyperparathyroidism. An early accurate diagnosis is very important since surgery is the most effective therapeutic approach to parathyroid carcinoma. Prognosis is quite variable and stress is laid on the early diagnosis and radical surgery which seem to be most favorable prognostic factors. An accurate follow-up should include frequent measurements of serum calcium and PTH levels to promptly detect recurrence or metastases which are usually associated with severe hyeprcalcemia.

Metastases from non-small cell lung cancer: mediastinal staging in the 1990s--meta-analytic comparison of PET and CT.

PURPOSE: To meta-analytically compare 2-[fluorine 18]fluoro-2-deoxy-D-glucose positron emission tomography (PET) and computed tomography (CT) for the demonstration of mediastinal nodal metastases in patients with non-small cell lung cancer. MATERIALS AND METHODS: English-language reports on the diagnostic performance of PET (14 studies, 514 patients) and/or CT (29 studies, 2,226 patients) for demonstration of mediastinal nodal metastases from NSCLC were selected by using the MEDLINE database. In eligible studies, an objective diagnostic standard was used, data were presented to allow recalculation of contingency tables, and established diagnostic criteria were used for abnormal test results. Summary receiver operating characteristic (ROC) curves were calculated. RESULTS: Pooled point estimates of diagnostic performance and summary ROC curves indicated that PET was significantly more accurate than CT for demonstration of nodal metastases (P < .001). Mean sensitivity and specificity (+/- 95% CI) were 0.79 +/- 0.03 and 0.91 +/- 0.02, respectively, for PET and 0.60 +/- 0.02 and 0.77 +/- 0.02, respectively, for CT. The log odds ratios were 1.79 (95% CI: 1.49, 2.09) for CT and 3.77 (95% CI: 2.77, 4.77) for PET (P < .001). Subgroup analyses did not alter findings. CONCLUSION: PET is superior to CT for mediastinal staging of non-small cell lung cancer, independent of performance index or clinical context of PET imaging.

Brain uptake of iodine-131 metaiodobenzylguanidine following therapy of malignant pheochromocytoma.

Intracranial metaiodobenzylguanidine (MIBG) uptake is occasionally and only faintly visualized on diagnostic studies. Recently, intense normal cerebellar uptake was described on posttherapy MIBG images. Experience at the University of Michigan with posttherapy MIBG scintigraphy of pheochromocytoma was reviewed. The patterns and correlates of intracranial uptake after therapeutic 1-131 MIBG in 25 patients (61 patient treatment encounters) were evaluated by review of records and blinded consensus interpretation of diagnostic and posttherapeutic MIBG scans. Thirty-nine (64%) patient treatment encounters demonstrated at least faint (grade 1) MIBG uptake in one or more brain sites; the most common site was the cerebellum. There was a statistically significant relation between intracranial uptake and 1) size of therapeutic dose and 2) patient age, but no relation between intracranial uptake and gender, body mass index, plasma epinephrine level, plasma norepinephrine level, urine metanephrine level, or the therapy-to-imaging interval. Although the influence of age on the pattern and intensity of intracranial uptake is unexplained, the relation to therapy dose may be explained by the possible generation of MIBG metabolites that can cross the blood-brain barrier (high activity administered and the delay until imaging). Further studies are needed to define mechanisms of intracranial uptake and relation to responses and toxicity after MIBG therapy of neuroendocrine tumors.

Diagnostic evaluation of the adrenal incidentaloma: decision and cost-effectiveness analyses.

UNLABELLED: The goal of this study was to examine the clinical and economic outcomes of alternative diagnostic strategies for differentiating benign from malignant adrenal masses. METHODS: We used cost-effectiveness assessment derived from decision analysis and the economic perspective of the payer of health care services. One-time evaluation with fine-needle aspiration (FNA) and combinations of chemical-shift MRI, noncontrast CT, 131I-6beta-iodomethylnorcholesterol (NP-59) scintigraphy, with or without FNA, in a hypothetical cohort of 1000 patients with incidentally discovered unilateral, nonhypersecretory adrenal masses. We calculated and compared the diagnostic effectiveness, costs and cost-effectiveness of the alternative strategies based on estimates from published literature and institutional charge data. RESULTS: At an assumed baseline malignancy rate of 0.25, diagnostic utility varied from 0.31 (CT0) to 0.965 (NP-59) and diagnostic accuracy from 0.655 [noncontrast CT using a cut-off attenuation value of > or = 0 (CT0)] to 0.983 (NP-59). The average cost per patient per strategy ranged from $746 (NP-59) to $1745 (MRI +/- FNA). The best and worst potential cost-to-diagnostic utility ratios were 773 (NP-59) and 2839 (CT0) and 759 (NP-59) and 1982 (MRI +/- FNA) for cost and diagnostic accuracy, respectively. The NP-59 strategy was the optimal choice regardless of the expected outcome examined: cost, diagnostic utility, diagnostic accuracy or cost-effectiveness. Varying the prevalence of malignancy did not alter the cost-effectiveness advantage of NP-59 over the other diagnostic modalities. CONCLUSION: Based on available estimates of reimbursement costs and diagnostic test performance and using reasonable clinical assumptions, our results indicate that the NP-59 strategy is the most cost-effective diagnostic tool for evaluating adrenal incidentalomas over a wide range of malignancy rates and that additional clinical studies are warranted to confirm this cost-effectiveness advantage.

Focal hyperemia on RBC blood-flow imaging. A scintigraphic marker of arterioportal venous shunting in hepatic cavernous hemangiomas?

PURPOSE: To investigate the significance of increased perfusion associated with some hepatic hemangiomata during radionuclide blood volume imaging. METHODS: Immediate dynamic planar projections and delayed SPECT imaging of a hepatic lesion were obtained after the administration of Tc-99m-labeled RBC. Scintigraphic data were compared with X-ray CT, contrast angiography and postresection histopathology. RESULTS: A surgically proven, cavernous hemangioma with typical findings on delayed radionuclide blood-pool imaging showed markedly increased perfusion by scintigraphy. This correlated with arterioportal venous shunting (AVPS) on contrast angiography. CONCLUSION: Increased perfusion on radionuclide blood-volume imaging of hepatic hemangiomata may be a scintigraphic marker of AVPS. This may serve to identify patients with increased risk for spontaneous rupture or may identify them for the development of portal hypertension.