Resolution of pulsatile tinnitus following an upper mediastinal lymph node resection.

External compression of extracranial/mediastinal vessels has not been reported as an etiology of pulsatile tinnitus. We present a case in which compression of extracranial vasculature led to long term pulsatile tinnitus which resolved completely with surgical resection of metastatic lymph nodes. This should be included in the list of differential diagnoses when dealing with any patient with a complaint of pulsatile tinnitus. Patients with advanced carcinoid cancer often present with distant metastases to their left superior mediastinum and supraclavicular lymph node chain. We believe a careful search for nodal metastases compressing vascular structures in such patients is warranted as debilitating pulsatile tinnitus may be cured by a simple surgical procedure.

Development of a highly sensitive and specific carboxy-terminal human pancreastatin assay to monitor neuroendocrine tumor behavior.

OBJECTIVE: Pancreastatin is a fragment of the chromogranin A (CgA) molecule. Existing pancreastatin assays, which depend on antibodies that cross-react in varying percents with the larger prohormone, may lack sensitivity and specificity to detect small changes in neuroendocrine tumor volume. METHODS: We developed a highly specific, sensitive pancreastatin assay. The antibody used recognizes the carboxyl terminal of the peptide hormone and was raised against a 17-amino acid porcine pancreastatin fragment with high homology with the carboxy-terminal amino acids 286-301 of the human CgA. RESULTS: Our assay measures more than 95% of circulating pancreastatin levels; has little or no cross-reactivity with CgA, even at plasma concentrations of 1000 ng/mL; and can detect pancreastatin levels of 17 pg/mL. Interassay reproducibility for the pancreastatin radioimmunoassay was determined from results of 3 quality control pools in 15 consecutive assays. Coefficients of variation for low, medium, and high pancreastatin levels were less than 20%. The sensitivity of serial pancreastatin assays to detect early liver tumor activity was demonstrated in 2 patients with slowly progressive neuroendocrine tumors and in patients undergoing surgical cytoreduction. CONCLUSIONS: This highly specific, sensitive pancreastatin assay can detect small changes in liver tumor progression and is up to 100-fold more sensitive and specific than CgA assays in the United States.