Multimodality treatment of neuroendocrine tumors of the thymus.

BACKGROUND: Neuroendocrine tumors of the thymus are rare neoplasms. Four patients with this tumor who underwent multimodality treatment are presented and the literature is briefly reviewed. METHODS: The medical records of all patients treated for neuroendocrine tumors of the thymus from 1979 to 2002 were reviewed. Tumors were classified using a slight modification of the World Health Organization criteria. RESULTS: The patients' median age was 38 years. All patients underwent extensive excision of the tumor. Histological diagnosis was atypical carcinoid (2), typical carcinoid (1), and small cell carcinoma (1). All patients developed recurrence(s). One patient died 132 months after diagnosis. The remaining three patients are alive with no symptoms at 135, 99, and 35 months, respectively, after diagnosis. Two patients with recurrences have been on treatment with Octreotide LAR with satisfactory results. One patient is free of disease. CONCLUSIONS: Neuroendocrine tumors of the thymus are potentially aggressive tumors. Radical resection is the treatment of choice. The encouraging results obtained by administration of Octreotide LAR in two of our patients warrant further investigation.

Effect of vasa vasorum flow on structure and function of the aorta in experimental animals.

BACKGROUND: It is known that vasa vasorum flow contributes substantially to the nutrition of the outer layers of the thoracic aorta. This investigation was undertaken to test the hypothesis that impairment of vasa vasorum flow would alter the structure of the aortic wall and change the elastic properties of the aorta. METHODS AND RESULTS: The periaortic fat that contain the vasa vasorum for the ascending aorta was removed in seven anesthetized dogs, and the results were compared with those obtained from six weight-matched sham-operated control dogs. Aortic pressures, aortic diameters, and aortic distensibility were obtained before and 30 minutes and 15 days after removal of the periaortic vasa vasorum network. Aortic pressures were measured directly with a fluid-filled catheter. Aortic diameters were measured simultaneously with aortic pressures with an elastic, air-filled ring connected to a transducer. Aortic distensibility was calculated by the formula 2 x pulsatile change in aortic diameter/(diastolic aortic diameter x pulse pressure). Histology was performed in transverse blocks of aortic wall at the end of the experiment in both groups. The efficacy of the technique for the interruption of vasa vasorum blood supply to the aortic wall was demonstrated by histology in four additional animals that were killed without removal of vasa vasorum (two animals) and immediately after vasa vasorum removal (two animals). At baseline, heart rate, aortic pressures, aortic diameters, and aortic distensibility were similar in the two groups. A significant decrease in aortic distensibility was observed 30 minutes and 15 days after removal of the vasa vasorum in the experimental group (baseline, 3.453 +/- 1.023; 30 minutes, 2.521 +/- 0.760; 15 days, 1.586 +/- 0.488 10(-6).cm2.dyn-1; F = 9.532, P < .001). No changes were observed in aortic distensibility in the control group during the experiment. Histology of the aorta revealed medial necrosis, alterations of the elastin fibers, and a trend (P = .055) for altered collagen-to-elastin ratio in a region occupying more than the one (outer) half of the media of the experimental group animals. No changes were observed in the control group. CONCLUSIONS: The findings of the present study demonstrated that interruption of vasa vasorum flow led to an acute decrease in the distensibility of the ascending aorta. Moreover, structural changes of the aortic wall and further deterioration of the elastic properties of the aorta occurred 15 days after vasa vasorum removal.