Many nodular lesions are incorrectly termed 'cysts'. Tumourous
lesions can be approached using the tests described under nodules,
although wider assessment of neoplasms is required ('staging').
Tumour
A large mass involving skin structures. The term is
often used in relation to neoplasia but can technically be
used in inflammatory disease.
Cyst
A cavity with an epithelial lining.
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Hair follicle tumour on the head
of a guinea pig