ABSTRACT
Cardiac tumors may represent mechanical causes for syncope by limiting left ventricular filling and/or by obstructing the left ventricular outflow tract. Malignant melanoma is known to metastasize to the myocardium or pericardium, but there are only a very limited number of reports describing endocardial involvement by the tumor. We describe herein an 84-year-old woman who presented with daily near-syncope episodes, 9 years after treatment for a choroidal melanoma. The echocardiography and the pathologic examination revealed a metastatic melanoma. This is the first reported case of an ocular melanoma metastasizing to the heart and presenting as a left ventricular intracavitary pedunculated mass.
Subject(s)
Choroid Neoplasms/pathology , Heart Neoplasms/secondary , Melanoma/secondary , Syncope/etiology , Ventricular Outflow Obstruction/complications , Aged , Aged, 80 and over , Choroid Neoplasms/complications , Diagnosis, Differential , Echocardiography , Fatal Outcome , Female , Heart Neoplasms/complications , Heart Neoplasms/diagnosis , Heart Neoplasms/surgery , Heart Ventricles/diagnostic imaging , Heart Ventricles/pathology , Humans , Magnetic Resonance Imaging , Melanoma/complications , Melanoma/diagnosis , Melanoma/surgery , Syncope/diagnosis , Ventricular Outflow Obstruction/diagnosis , Ventricular Outflow Obstruction/etiology , Ventricular Outflow Obstruction/surgeryABSTRACT
Phospholipid synthesis was investigated in human Y79 retinoblastoma cells, a cultured cell line of retinal origin that retains many neural characteristics. Ethanolamine is taken up by Y79 cells through a high-affinity transport system and is utilized to synthesize ethanolamine and choline phosphoglycerides. High-affinity ethanolamine uptake has a K'm of 40.6 microM and a V'max of 1.06 nmol/min/mg protein, and the process is Na+ dependent. Choline is the only compound tested that reduced ethanolamine uptake, and very high choline concentrations were required to produce this effect. The cells incorporate ethanolamine into phosphatidylethanolamine and ethanolamine plasmalogen at equivalent rates, and the rates of catabolism of these phospholipids are similar. Only a small quantity of ethanolamine is incorporated into phosphatidylcholine, but the amount is not reduced by the addition of choline. Serine is incorporated into phosphatidylserine, which then is converted to phosphatidylethanolamine. Ethanolamine reduces but does not abolish this conversion. Unlike ethanolamine, only a small amount of serine is incorporated into ethanolamine plasmalogen. It is possible that the ethanolamine high-affinity uptake system is necessary to provide a neural cell with enough free ethanolamine for ethanolamine plasmalogen synthesis.
