Cappuccino, a beautiful orange tabby cat, had been the picture of health most of her life. Then, when she was 11 years old, we noticed some minor abnormalities during her annual physical exam. A little weight loss. A slight increase in heart rate. A tiny nodule on her thyroid gland. Her owner agreed to basic blood tests to evaluate her condition, and we quickly discovered our old friend had a case of hyperthyroidism. One of the most common endocrine abnormalities in older cats, hyperthyroidism is usually caused by a benign but hormone-secreting tumor of the thyroid gland. The excessive thyroid hormone increases the cat’s basal metabolic rate ( I often liken it to turning up the thermostat in your house), typically resulting in classic signs of increased appetite combined with weight loss.
There are several options for treating feline hyperthyroidism. The gold standard is an injectable radioactive iodine therapy that cures more than 98 percent of all cases. It is moderately expensive, and requires three to five days’ hospitalization at a specially licensed facility off-Island, followed by several weeks of specific post-treatment home care. For those choosing not to pursue this definitive cure, there is oral medication that, given daily, lowers production of thyroid hormone to normal, thus controlling the symptoms. Cappuccino’s owner wanted time to consider radioiodine therapy, so we began oral medication. She soon found Cappy took her pills easily and was doing well, so, for the time being, opted to maintain her on oral medication.
We rechecked Cappuccino every six months, and she continued to thrive. Then, almost two years later, at one of her routine monitoring appointments, her owner mentioned she had recently developed a spattering of scabs across the bridge of her nose. There were eight or nine scabby little bumps, ranging in size from one to three millimeters, that had been there several months. “This looks just like a case of mosquito bite hypersensitivity,” I said. Mosquito hypersensitivity is an uncommon seasonal disease in cats who have become abnormally sensitive to bug bites. The bridge of the nose and ears are the most thinly furred areas on kitties, thus the prime target for mosquitoes. When a cat’s immune system overreacts to these bites, the nose and/or ears get covered with crusty, itchy bumps.
But Cappuccino had never exhibited any sign of allergies before … and it was December. Not exactly mosquito season. Flea allergy can very occasionally present this way, but Cappuccino had a Seresto collar and zero evidence of flea infestation. Other diagnoses on my differential list included ringworm, allergic reaction to the thyroid medication, autoimmune disease, food allergy, mange mites, and cancer. “We would need a biopsy to get a definitive answer,” I told Cappy’s mom, but since the lesions were mild and recent in onset, we decided to start with a topical ointment containing a mix of antibiotic, antifungal, and antiinflammatory medications.
Three months later, the lesions were unchanged. Skin scrapings ruled out mites. Fungal culture ruled out ringworm. “I can’t imagine after two years on her thyroid medication that she has suddenly developed a reaction to that,” I said. I sent Cappuccino’s test results and a photo of her nose to a dermatologist. “Sure looks like mosquito bite hypersensitivity,” he texted. “But could be squamous cell carcinoma.” He agreed that a course of oral corticosteroids was worth trying. If the issue was allergic, that should clear up the lesions. If not, well, then it was time to biopsy.
At first corticosteroids seemed to be helping, but after a month it became clear that although the medication was reducing the general inflammation across the nose, the lesions themselves were not resolving. In fact, one area had now coalesced into a larger, harder growth. “I think I can shave off a portion of that bump for a biopsy without any anesthesia,” I told her owner. She was always an easy patient, so I was not surprised when Cappuccino sat calmly while I used a small scalpel to quickly slice off a sample for the pathologist. One week later, we had our answer.
Squamous cell carcinoma (SCC) is a relatively common malignant cancer that occurs in many species and in many locations on the body. In cats, SCC of the skin typically develops on areas with most exposure to ultraviolet light — the lightly furred bridge of the nose and the ears. It is most common in white or light-colored cats.The growths often occur in situ, which means they are very localized and do not metastasize. (This is sometimes referred to as Bowen’s disease.) At this stage the condition doesn’t seem to bother the cat. Left untreated, it often progresses to more aggressive, invasive squamous cell carcinoma, which may be painful, with deep, ulcerated lesions. Rarely, SCC may spread to other parts of the body, in which case a cat may show signs of generalized illness, such as weight loss, poor appetite, or labored breathing.
The only cure for in situ SCC is aggressive surgical intervention, removing a good portion of nose, not just skin. It can be difficult to achieve cosmetic results acceptable to owners, and complications such as loss of appetite and infection can occur. Other treatment options available through specialists may include radiation, cryotherapy, and chemotherapy. Since Cappuccino is almost 13 years old, and also hyperthyroid, her owner has opted not to pursue invasive treatments … but we have another option. Imiquimod ointment, also know by the brand name Aldera, is a topical preparation used to treat skin conditions in people such as actinic keratosis and some forms of superficial skin cancer. In cats with nasal SCC, imiquimod, applied to the lesions every one to three days, will sometimes lead to remission, or at least slow the progression. It is unlikely to cure Cappuccino, but may well control her cancer for six to nine months, maybe more, maintaining her quality of life as long as possible. We still think she’s a beautiful orange girl, even with those bumps on her nose.