phe·o·chro·mo·cy·to·ma 
(fē′ō-krō′mō-sī-tōmə)
(fē′ō-krō′mō-sī-tōmə)n. pl. phe·o·chro·mo·cy·to·mas or phe·o·chro·mo·cy·to·ma·ta (-mə-tə)
A usually benign tumor of the adrenal medulla or the sympathetic nervous system in which the affected cells secrete increased amounts of epinephrine or norepinephrine.
[pheochromocyte, chromaffin cell (Greek phaios, dusky + CHROMO- + -CYTE) + -OMA.]