Ocular tumor identification in dogs and cats often entails diagnosis difficulties, as patients are frequently brought to consultation with rather advanced symptoms and lack of clearness of the structures.

Echography of the eye, performed with the aid of an Ophthalmologic Echographer (10-20 Mhz probes, with modes A and B, as well as modular vector) is a useful tool, often indispensable, for ocular tumor identification and analysis.

Mode B echography provides topographic information on the tumor (location, structures affected, size and shape variations over time...).

Mode A echography permits one to study ultrasound behaviour as they pass through different tissues and thereby check the structure of the various tumor types. Each tumor type provides a series of echoes which may become rather characteristic, hence they are very helpful in clinical diagnosis. Thus, we can talk of ultrasonic-tissular correlation.

Tissular, cellular, intercellular and vascular characteristics of a tumor provide Mode A echoes that can be studied from two parameters:

Homogeneity

When echoes tend towards uniformity with scarce difference between maximum and minimun picks as obtained. Heterogeneity stands for the opposite situation, with a great difference between maximum and minimum echoes.

Reflectivity

Echo intensity is the most important piece of information provided by analysis in Mode A, as the most differentiated and least malignant tumors provide echoes with higher intensity (melanomas and adenomas). Conversely, echoes with low intensity are common in undifferentiated and more malignant tumors (lymphoma-lymphosarcomas, feline diffuse melanoma...).

Future studies comparing high-resolution echographic characteristics to anatomicopathological tissue characteristics will permit a higher degree of tumor characterization, needed to therapeutically address an ocular tumor.

References

1.  Fernández Vigo Lopez J. Diagnostico ecográfico en patología ocular y orbitaria. Barcelona: Ed. Pujades, 1986.

2.  Gelatt K.N. Ophthalmic examination and diagnostic procedures. In: Veterinary Ophthalmology. 2ª ed. Philadelephia: Ed. Lea and Febiger, 1991: 230.

3.  Simón M. Diagnostic échografique en ophtalmologie. Encyclopédie Vétérinaire. Paris. Éd. (Elsevier), Imaginerie 3000, 10 p.