Primary Tumors of the Lung in Nonhuman Primates; Literature Review and Report of Peripheral Carcinoid Tumors of the Lung in a Rhesus Monkey

Abstract

Primary lung tumors in nonhuman primates are reviewed, and multifocal carcinoid tumors in the periphery of the lungs of a 6-year-old female Rhesus monkey (Macaca mulatto) are discussed. The tumors consisted almost entirely of neoplastic cells that were pleomorphic, had round to oval nuclei, 0 to two nucleoli, clear or slightly amphophilic cytoplasm, and indistinct cell boundaries. The cells generally formed solid sheets, supported by an elaborate network of reticulin. Electron microscopic examination showed distinct but irregular cell membranes and a paucity of electron-dense material in the cytoplasm of many cells.