No abstract

Primary hepatic neuroendocrine carcinoma is an extremely rare tumor of the liver. We herein describe a case of primary hepatic neuroendocrine carcinoma with lymph node metastases, coexisting with hepatocellular carcinoma, on a background of hepatitis C cirrrhosis, in a 72-year-old man. Abdominal ultrasonography and computed tomography (CT) showed a tumor (3 cm in diameter) in Couinaud's hepatic segment 8 (S8) with regional lymph node metastases. Whole-body CT, magnetic resonance imaging (MRI), and endoscopy did not reveal primary lesions outside the liver. Feridex MRI and [(18)F]fluorodeoxyglucose positron emission tomography were strongly suspicious of malignancy. A limited hepatectomy with regional lymph node dissection was performed. Histopathology, immunohistochemistry, and electron microscopy confirmed a diagnosis of primary neuroendocrine carcinoma on a background of liver cirrhosis. A tumor (1.5 cm in diameter) found in hepatic S5 at operation was also simultaneously resected, and histologically diagnosed to be hepatocellular carcinoma. We also review previous reports of hepatic neuroendocrine carcinoma and discuss hypotheses for the histogenesis of these tumors as well as prognostic implications. Given the background cirrhosis and coexisting hepatocellular carcinoma, we speculate that one of the hepatocellular carcinomas underwent neuroendocrine differentiation.

To clarify the role of vitamin D in the regula-

CD44v6 protein may have an important role in hematogenous metastasis, and may be a biologic marker of prognostic significance in differentiated type gastric cancers.

To examine a possible role for atrial natriuretic peptide (ANP) in water and sodium metabolism disturbances associated with abnormal vasopressin (AVP) secretion, we measured plasma ANP concentrations in 15 patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and in 17 patients with central diabetes insipidus (DI). The mean plasma ANP concentration (30.2 +/- 10.4 pmol/L) in SIADH patients who had hyponatremia, plasma hypoosmolality, hyperosmolar urinary compared to plasma sodium levels, and increased plasma AVP levels relative to plasma osmolality was significantly higher than that in normal subjects (12.6 +/- 4.9 pmol/L), although there was a considerable individual variation in plasma ANP ranging from normal to clearly elevated levels (15.1-47.0 pmol/L). When hyponatremia was corrected by water restriction or demeclocycline administration, plasma ANP levels decreased significantly and fell into the normal range (12.5 +/- 4.3 pmol/L). DI patients who complained of polyuria and polydipsia and had hypoosmolar urine, normal or elevated plasma sodium concentrations, and decreased plasma AVP levels relative to plasma osmolality, on the other hand, had a significantly lower mean plasma ANP level (7.6 +/- 2.9 pmol/L) than normal subjects. There was, again, a considerable overlap between plasma ANP levels in individual DI patients (4.2-13.9 pmol/L) and those in normal subjects. Treatment with 1-desamino-8-D-arginine vasopressin resulted in a significant increase in the mean plasma ANP level (18.6 +/- 8.0 pmol/L). There were no significant correlations between plasma ANP and AVP levels in either group of patients. The results indicate that ANP secretion is modulated by changes in plasma volume consequent to abnormal AVP secretion, which may have a pathophysiological significance in maintaining volume homeostasis.