Submitted to: American Association of Avian Pathologists
Publication Type: Review Article
Publication Acceptance Date: May 15, 2005
Publication Date: May 15, 2005
Citation: Witter, R.L., Gimeno, I.M., Fadly, A.M. 2005. AAAP Continuing Education Program Slide Study Sets: Differential diagnosis of lymphoid and myeloid tumors in the chickens [CD-ROM]. Set 26 & 27. Athens, Georgia: American Association of Avian Pathologists (AAAP). Technical Abstract: This slide set and associated text is to assist diagnosticians and veterinary pathologists in making accurate diagnoses of field cases in chickens where lymphoid or myeloid tumors are suspected. Lesions and other diagnostic features that distinguish Marek's disease (MD), lymphoid leukosis (LL), myeloid leukosis (ML) and the bursal and nonbursal lymphomas induced by reticuloendotheliosis (RE) virus (REV) are discussed and illustrated. Differentiation of these neoplasms from nonneoplastic syndromes and assorted other tumors is also discussed. Emphasis is placed on diagnostic strategies rather than specific procedures. A system is proposed by which a diagnostic case is first assigned to one of four clinical types based mainly on gross lesions and age. This approach reduces the number of possible conditions to be considered, thus simplifying the process. Differential diagnosis continues to be based primarily on gross and microscopic lesions. Additional tests of proven value for diagnosis include determination of T-cell and B-cell frequency and, if retroviral tumors are suspected, demonstration of clonal insertions adjacent to the c-myc oncogene. Tests for specific viruses or their antibodies have only limited value, but can be adjuncts to other methods in some cases. Several additional tests with potential value are presented to encourage further development and field testing by reference laboratories.