Pseudoneoplasms in ectothermic animals

Area of Science:

• Comparative Pathology
• Herpetology
• Ichthyology

Background:

• Neoplastic and non-neoplastic lesions in lower vertebrates often exhibit similar gross and cytologic features.
• This morphological overlap can lead to diagnostic challenges and misinterpretations in veterinary pathology.

Purpose of the Study:

• To systematically review and categorize pseudo-neoplastic conditions in lower animals.
• To provide diagnostic criteria for differentiating non-neoplastic lesions from true neoplasms in fish, amphibians, and reptiles.

Main Methods:

• Review of cases accessioned into the Registry of Tumors in Lower Animals.
• Morphological analysis (gross and cytologic) of various non-neoplastic conditions.
• Classification of pseudo-neoplasms into major categories based on etiology.

Main Results:

• Identified and illustrated major categories of pseudo-neoplasms, including infections (protothecosis, amebiasis), unusual normal conditions (ectopic pancreatic islets), nonparasitic hyperplasia (goiter), parasite-induced hyperplasia (trematodiasis, glochidiosis), dysmorphogenesis, virus-induced hypertrophy (lymphocystis), and reactive lesions.
• Provided specific examples for each category.

Conclusions:

• Accurate differentiation of pseudo-neoplasms from true neoplasms is crucial for correct diagnosis in lower animals.
• Understanding these mimetic lesions improves diagnostic accuracy and aids in comparative oncology research.