Paraganglioma
Clusters of neuroendocrine cells are distributed throughout the neck, thorax, abdomen, and pelvis; they can give rise to tumors called paragangliomas or chemodectomas. Here is a case of a paraganglioma in the uterine cervix. Higher magnification (inset) shows large polygonal cells with abundant clear or eosinophilic granular cytoplasm. The cells tend to cluster in nests (zellballen). See also Head and Neck; carotid body tumor.