Spontaneous pulmonary neoplasms in cynomolgus monkeys (Macaca fascicularis) - A report of two cases

The first lung tumour-bearing animal was a 7 years and 3 months old cynomol gus monkey. Microscopic examination revealed a neoplastic mass under the pl eura that consisted of squamous islands with little keratinization, multifo cal mineralization of the keratin, inflammatory cell and foreign body-type giant cell infiltration. It was classified as pulmonary squamous cell carci noma. In a second cynomolgus monkey (2 years and 10 months old) a lung mass was observed at necropsy. Microscopically the tumour consisted of numerous islands of cartilage with glandular structures lined by a cuboidal epithel ium between them. The neoplasm was classified as cartilaginous hamartoma.