Walter was a beagle-springer cross, so I was not surprised that he had an ear infection. Those breeds are both prone to otitis externa, the technical term for an ear infection. You know — when the canal gets all red and oozes that smelly, gooey discharge. Otitis may be caused by yeast or bacteria — sometimes both — and often is initiated by underlying issues such as allergies, frequent swimming, or problems with the anatomical conformation of the ear canals. We treated Walter with a standard ointment, a combination of antifungal, antibiotic, and anti-inflammatory medications. The otitis resolved but then quickly recurred.
“Let’s see what organisms are in there,” I suggested, smearing the green goop I had extracted from Walter’s ear onto a slide, which my assistant heat-fixed and stained. “Lots of cocci bacteria,” I concluded, examining the slide on the microscope. A pretty routine staph infection. Walter also happened to be diabetic, making him more susceptible to infections in general. We dispensed a second ear medication. The otitis got better . . . then recurred . . . again. This time as I tried to clean it, the canal began to bleed, and Walter was too tender to let me look down with my otoscope.
When faced with a stubborn case of otitis, there are several things we can try. We could take a culture and see exactly what organisms were growing in Walter’s ear. The laboratory could then run an antibiotic-sensitivity panel to determine the most effective drugs. But some specialists say that culturing an ear is like culturing the inside of a garbage can. You’re going to grow a lot of stuff, but not all the information you get will be useful. Instead, we decided to try a special brew many veterinarians mix up for such situations.
We start with a liquid called trizEDTA, which breaks down bacterial cell walls, allowing antibiotics to then penetrate into the organisms and fight the infection more effectively. Adding liquid antibiotic to a big bottle of trizEDTA, I instructed Walter’s mom to fill his ears liberally with the fluid twice daily for two weeks. “This should fix him up,” I said confidently. Then, almost as an afterthought, I suggested a recheck in a few weeks. Six weeks later, Walter was back. Once again, the infection had responded, only to rapidly recur when the owner stopped the medication. “OK, let’s see what’s going on,” I sighed, thinking it was time to take a culture, and wheeling over my bright exam light to get a good look. I pulled up Walter’s ear and gazed carefully into the canal. Oh, my. I hadn’t seen that before. A small, red, cauliflower-like mass deep in his ear. “He’s got a growth in there,” I said. At past visits a combination of tenderness, blood, and discharge had made it difficult for me to see what was probably a small growth back then, which had now grown and was easily visible. (Or maybe I just hadn’t looked hard enough.)
Ear tumors are relatively uncommon in dogs, occurring primarily in middle-aged or senior pets. They can affect the flap, canal, or middle or inner ear, and can grow out of the skin, connective tissue, or various glands. They can be benign or malignant. Often there are no obvious clinical signs, depending on where the tumor is, what kind it is, and how fast it grows. If the tumor occurs in the middle or inner ear, neurological and balance problems may occur, resulting in walking problems, facial-nerve paralysis or head tilt. As they did with Walter, ear tumors may lead to secondary infection as they occlude the canal, hindering air flow and trapping debris and wax.
“A lot of times with ear tumors, it’s impossible to remove the whole cancer without removing large portions of the ear canal,” I told his mom. But we needed to start somewhere, so we scheduled surgery to remove as much as we could without being too invasive, and sent out a biopsy. My hope was that it would be benign and thus not a big problem, even if we had to leave a little behind.
No such luck. Walter’s biopsy came back as ceruminous adenocarcinoma, a malignant cancer originating in the wax glands lining the ear canal. Although in dogs these tumors have only about a 10 percent chance of metastasis (i.e., spreading to other places such as lungs or lymph nodes), they tend to be locally invasive and aggressive. After consulting with a veterinary oncologist, Walter’s mom and I discussed the bad news. “If you decide to pursue treatment, we start by taking chest x-rays and a lymph-node aspirate to make sure it hasn’t metastasized,” I said. “Then a CT scan gets done off-Island at the specialists’ to determine how far it has spread inside the ear.” Then, more surgery. Although benign tumors can be removed with less extensive procedures, for this malignant cancer the oncologists advise total ear-canal ablation (TECA), which essentially removes all the ear structures while leaving the flap intact. In about one-quarter of cases, such cancers extend into the tympanic bulla on the skull, in which case the surgeon would also open this area and remove any abnormal tissue in a procedure called a bulla osteotomy. Postoperative complications might include facial-nerve paralysis, healing difficulties, and, of course, deafness on one side.
Walter is not a young dog, and his diabetes increases the potential for poor healing. There are only limited studies tracking the prognosis for dogs in Walter’s situation. Expected survival time for dogs with ceruminous adenocarcinoma who have the TECA surgery is reported to range from one to three years, but these statistics are based on very small numbers of cases. Without treatment, the oncologist says, Walter may develop trouble with his balance as the tumor spreads, and become severely uncomfortable within one year. His mom is considering their options, weighing all these factors . . . and I am taking a good long look down the ears of every dog who comes in with recurrent otitis.