This month we'll have the first of a few cases looking at various lumps and bumps.

 

ONE LUMP OR TWO?

 

HISTORY

Punchy was a 6-year-old German Shepherd mix dog who came to us for examination of a lump on her side. She'd had it for only a few months, and it seemed to be getting bigger.

 

PHYSICAL FINDINGS

Except for the lump, which was a firm growth in the skin over her ribs, Punchy's exam was normal.

 

TEST RESULTS

A very helpful tool for examining lumps is the needle aspirate. With this technique we draw a sample of cells through a fine needle (the same we'd use for typical injections), stain them with special dyes to make them easier to see, and examine them under the microscope. Here's what we saw with Punchy:

So, what is all this stuff? We've got several different things on this slide.

First, the medium-sized pinkish purple circles are red blood cells. We can see red blood cells as a result of bleeding, irritation, or anything causing leaky blood vessels. There are many on this slide, and some overlap so they look like they're stuck together.
Next, we have little pink and purple spots all over the place. These are granules that have been released from the cells we'll talk about next.
Finally, we have the source of all the granules. What you see here is a cell (or possibly two) in the process of releasing a bunch of granules. Some aspirates don't give us an immediate diagnosis, but this one did. The cells are mast cells, and what Punchy had was a mast cell tumor.

 

DISCUSSION

There are dozens of different types of tumors that pets can get. The term cancer is used by some people to refer to any tumor, while some only call malignant tumors "cancer." In Punchy's case, the tumor we found was malignant, so we scheduled surgery to remove it as soon as we could. A biopsy confirmed our initial concerns.

Mast cells are normal cells present in the body and involved in inflammatory responses. The granules they carry and release contain several substances that create and influence inflammation; the most familiar is probably histamine. Know anyone with allergies? Histamine is often responsible for much of what we see with allergies (thus we use anti-histamines to fight allergies). Excessive release of materials from mast cells can cause symptoms as different as stomach ulcers, hives, and life-threatening shock.

So far (about 6 months after surgery), Punchy's doing well. We were able to remove all of the tumor that was present, but there are cases where tumors can reappear in the same place, show up someplace else, or spread to internal organs (metastasize). We'll have to keep a close watch on Punchy to be sure the cancer doesn't return.

We hate to see cancer, but as people's pet's are living longer, we are seeing more of it. Next month we'll give you another example...

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