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External ear tumors in cats
Advances
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Results Cytologic and histologic diagnoses had a good overall agreement (index of 0.74), a diagnostic odds ratio of 22, and 100% (27/27) agreement in the diagnosis of inflammatory polyps versus neoplasia (both benign and malignant). Author Conclusion FNB cytopathology of external ear masses in the cat distinguishes inflammatory polyps from neoplasia. Differentiation of benign proliferation and malignant neoplasia requires histopathologic examination. Inclusions Five figures, 4 tables, 23 references.
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Dermatology
External Ear Tumors in Cats Background Types of tumors in the external ear canal of cats are difficult to identify. The cytologic diagnosis of ear canal tumors by swab alone is difficult to impossible because cell exfoliation is often poor and cells of inflammation may hide cells from a neoplasm. Fine-needle biopsy (FNB) may be more useful in obtaining a higher yield of pertinent cells for diagnosis. Objectives To assess the efficacy and diagnostic value of FNB and cytologic examination in providing an accurate diagnosis of masses growing in the external ear canal of cats. Procedure Cytologic specimens were collected from masses in the external ear canal of 25 cats. Twenty-seven masses were discovered. Two of the 25 cats were affected bilaterally. Four tumor groups were identified: ceruminous gland hyperplasia or adenoma, ceruminous gland adenocarcinoma, inflammatory polyps, and other neoplastic and non-neoplastic masses. Cytopathologic diagnoses were compared with the final histopathologic diagnoses. Indices of diagnostic test accuracy were calculated.
Editor Annotation In this study, cytologic evaluation of needle biopsies (fenestration) of feline external ear canal masses was useful in diagnosing the type of mass present in the canal. The authors report that an inflammatory polyp can be reliably differentiated from a neoplastic mass using the technique. Although the authors determined that histopathology is needed for definitive diagnosis of a benign mass (adenoma) versus a malignancy (adenocarcinoma), the fine needle biopsy was accurate in the majority of the cases (7 of 11 adenomas and 6 of 7 adenocarcinomas). When there was discrepancy between the fine needle biopsy and the histopathology of the mass, cytologic examination for the fine needle biopsy generally overestimated the malignancy of the tumor. This fine needle biopsy technique has several benefits: it is relatively easy, inexpensive, and noninvasive. The ability to determine the type of tumor (adenoma, inflammatory polyp, or mast cell tumor) present in the ear canal prior to a surgical procedure is very helpful when the veterinarian is considering surgical options for their patient. For example, an inflammatory polyp may be removed via a bulla osteotomy; whereas, an animal with an adenocarcinoma will likely require a total ear canal ablation. (JLM) Lorenzi DD, Bonfanti U, Masserdotti C, et al. Fine-needle biopsy of external ear canal masses in the cat: cytologic results and histologic correlations in 27 cases. Vet Clin Pathol 2005;34:100-105.
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Results Cytologic and histologic diagnoses had a good overall agreement (index of 0.74), a diagnostic odds ratio of 22, and 100% (27/27) agreement in the diagnosis of inflammatory polyps versus neoplasia (both benign and malignant). Author Conclusion FNB cytopathology of external ear masses in the cat distinguishes inflammatory polyps from neoplasia. Differentiation of benign proliferation and malignant neoplasia requires histopathologic examination. Inclusions Five figures, 4 tables, 23 references.
•
Dermatology
External Ear Tumors in Cats Background Types of tumors in the external ear canal of cats are difficult to identify. The cytologic diagnosis of ear canal tumors by swab alone is difficult to impossible because cell exfoliation is often poor and cells of inflammation may hide cells from a neoplasm. Fine-needle biopsy (FNB) may be more useful in obtaining a higher yield of pertinent cells for diagnosis. Objectives To assess the efficacy and diagnostic value of FNB and cytologic examination in providing an accurate diagnosis of masses growing in the external ear canal of cats. Procedure Cytologic specimens were collected from masses in the external ear canal of 25 cats. Twenty-seven masses were discovered. Two of the 25 cats were affected bilaterally. Four tumor groups were identified: ceruminous gland hyperplasia or adenoma, ceruminous gland adenocarcinoma, inflammatory polyps, and other neoplastic and non-neoplastic masses. Cytopathologic diagnoses were compared with the final histopathologic diagnoses. Indices of diagnostic test accuracy were calculated.
Editor Annotation In this study, cytologic evaluation of needle biopsies (fenestration) of feline external ear canal masses was useful in diagnosing the type of mass present in the canal. The authors report that an inflammatory polyp can be reliably differentiated from a neoplastic mass using the technique. Although the authors determined that histopathology is needed for definitive diagnosis of a benign mass (adenoma) versus a malignancy (adenocarcinoma), the fine needle biopsy was accurate in the majority of the cases (7 of 11 adenomas and 6 of 7 adenocarcinomas). When there was discrepancy between the fine needle biopsy and the histopathology of the mass, cytologic examination for the fine needle biopsy generally overestimated the malignancy of the tumor. This fine needle biopsy technique has several benefits: it is relatively easy, inexpensive, and noninvasive. The ability to determine the type of tumor (adenoma, inflammatory polyp, or mast cell tumor) present in the ear canal prior to a surgical procedure is very helpful when the veterinarian is considering surgical options for their patient. For example, an inflammatory polyp may be removed via a bulla osteotomy; whereas, an animal with an adenocarcinoma will likely require a total ear canal ablation. (JLM) Lorenzi DD, Bonfanti U, Masserdotti C, et al. Fine-needle biopsy of external ear canal masses in the cat: cytologic results and histologic correlations in 27 cases. Vet Clin Pathol 2005;34:100-105.