title: Naturally occurring squirrel fibroma with involvement of internal organs.
mesh_terms: D000818:Animals; D005350:Fibroma / Q000473:pathology / Q000662:veterinary*; D008113:Liver Neoplasms / Q000473:pathology / Q000662:veterinary; D008175:Lung Neoplasms / Q000473:pathology / Q000662:veterinary; D008854:Microscopy, Electron; D012376:Rodent Diseases / Q000473:pathology; D012589:Sciuridae; D012878:Skin Neoplasms / Q000473:pathology / Q000662:veterinary*; D013160:Splenic Neoplasms / Q000473:pathology / Q000662:veterinary