Today's Veterinary Practice

JAN-FEB 2016

Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.

Issue link: http://todaysveterinarypractice.epubxp.com/i/619503

Contents of this Issue

Navigation

Page 31 of 139

Today's VeTerinary PracTice | January/February 2016 | tvpjournal.com common neoPlasTic skin lesions in dogs & caTs Peer reviewed 30 removed with a lidocaine local block and skin punch biopsy. Canine MCTs are more locally invasive than the feline form; recommendations for complete surgical removal generally suggest excising the mass with 2- to 3-cm margins of visibly normal tissue included. A more recent study 2 reported on a modifed margin technique in which tumors are excised with lateral margins equal to the widest diameter of the tumor, up to a maximum of 4 cm. Forty dogs had tumors removed with clean margins, 7 had incomplete margins, and only one tumor was suspected to have recurrence. Histopathologic grading is critical to determine the likely systemic biologic behavior of any particular canine MCT, as well as the necessity for systemic therapy after excision. Squamous Cell Carcinoma Description. Squamous cell carcinoma (SCC) occurs primarily in older dogs and cats. Animals with lightly pigmented skin that spend time in the sun are predisposed to solar (actinic) induced SCC in their thinly haired areas. Multiple lesions may be present in these cases, particularly in white cats. In dogs, cutaneous SCC unrelated to sun exposure is the most commonly reported digital tumor and most often affects dark-haired dogs. 3 Diagnosis. On physical examination, cats present with facial lesions more frequently than dogs, usually at thinly haired areas, such as the ear tips, eyelids, and nasal planum. These lesions are often crusty and ulcerated. In dogs, digital SCC is usually single but may affect multiple digits in giant schnauzers and other large, black-haired breeds. SCC of the digit appears as a swollen digit with an abnormal nail; it is often diagnosed initially as a fractured nail with a nailbed infection (Figure 7). Cytology can be diagnostic for SCC of the digit (Figure 8). Direct the needle deep into the midpoint of the digit; the bone is often involved and lytic; therefore, a good sample may be obtained from the bone itself. Occasionally, dogs will have so much pain that sedation is needed for FNA. Management. SCC of the skin is a locally invasive tumor but rarely metastasizes; thus, the FIGURE 6. Cytology from the same sample as Figure 5, stained with a Wright-Giemsa stain; the mast cell granules now can easily be seen. The red cells also appear much more "red," and indistinct pink granules can be seen in the segmented cells, confrming that they are eosinophils (magnifcation, 20×). FIGURE 7. The shaved foot of a Gordon setter with a digital SCC, showing severe swelling of digit #5; a broken toe nail and some soft tissue proliferation with discharge are seen at the nail bed. FIGURE 8. Cytology of a SCC; note the large angular cells, some of which appear as individuals, while others appear to be joined. The cytoplasm ranges in color, with many showing deep blue consistent with keratinization. Features of malignancy, including anisocytosis and anisokaryosis, are prominent. Scattered neutrophils are present in the background.

Articles in this issue

Links on this page

Archives of this issue

view archives of Today's Veterinary Practice - JAN-FEB 2016