Off on a new ride

Yet another canser contender... but this time, of the feline crew, my beloved Orange Guy. He was diagnosed today with a mast tumour on his neck. He'll have it excised surgically next week but reading online, it sounds worse than just a little bump on his neck.

Feline

Mast cell tumors classically affect older cats; in one study the average age was 10 years. Pathologists divide mast cell tumors into two forms: Well Differentiated and Poorly Differentiated. The well differentiated tumor is generally more benign in its behavior while the poorly differentiated tumor behaves more malignantly. But mast cell tumors in cats are also classified by their location into two forms: cutaneous (located in the skin) and visceral (located internally). A very unlucky cat may have both.

Cutaneous Forms
The skin form of the feline mast cell tumor classically arises around the head and neck. Lesions may be solitary or multiple with the presence of multiple lesions not necessarily boding poorly (though if there are many mast cell tumors present, that would constitute rather a lot of inflammatory biochemicals about and more symptoms for the cat).

Treatment of choice would be surgical excision. If surgical excision is incomplete, radiation therapy as a follow-up is generally successful at "cleaning up" any leftover cells still present.

Visceral Form
As one might surmise, mast cell tumors located internally are more serious than those in the skin. The most common organs involved are spleen, liver, and intestine. Vomiting, appetite loss, and weight loss are the most common symptoms. As with the cutaneous form (but not as easily accomplished), surgery is the treatment of choice; no single chemotherapy protocol has emerged as being particularly successful above the others. Unlike the canine situation, it is not all that helpful to stage the disease with buffy coat smears and bone marrow taps (though localizing the disease to the spleen with a splenic aspirate might be particularly useful - see below) as presence of tumor cells in these locations has not altered prognosis for this disease. The most telling piece of information for prognosis actually comes from the history: appetite. Cats that are eating decently at the time they are first brought to the veterinarian have a median survival of 19 months, while cats that are not eating have a median survival of 8 weeks.

Splenic Mast Cell Tumor
Luckily, the spleen can be removed leading to a a rapid recovery. The median survival after splenectomy is 14 months (vs. 4-6 months if the spleen is left in place). This is not to say that the cat is cured with splenectomy, but removing the spleen frees the cat from the bulk of the mast cells quickly and it takes time for the tumor to regrow.

After diagnosis of mast cell tumor has been made, consider consultation with an oncologist for the most up to date information on chemotherapy or other adjunctive treatment.

Obviously I pray his is merely cutaneous. The vet said that had I brought him in much earlier, she wouldn't have been able to aspirate the lump and would have told me to wait. He'll be ten in October so he fits right in.