Diary of a Real-Life Veterinarian: How confidently can you diagnose your pets "bump" by a photo online? Histiocytoma or Mast Cell Tumor? Don't Guess Wrong!

Some interesting points to talk about from a question that came in to Pawbly today.

Pawbly Question:

"I think my dog has a histiocytoma on his leg based on pics online it has been getting bigger about size of my little finger end he has had it for one month hopefully it will go of its own accord any advice please?

thanks

From Aud Connor of the UK

The first answer came from Kaz Kallin;

..since it is growing rather rapidly I would recommend having it checked out by a vet who will most likely want to take a fine needle sample for a cytology to determine exactly what it is. Hystiocytomas are benign but I've seen quite a few mast cell tumors that look like Hystiocytomas. Mast cell tumors need to be removed with wide surgical margins. Best of luck.

..and the second answer came from me;

Hello,

I would absolutely, unequivocally, recommend that you see a vet as soon as possible. The leg is one of the common places that we see histiocytomas, but a mass on the leg can be much harder to remove because there is not much extra skin here and we need to both remove the mass with clean margins AND be able to close the remaining area. Surgical removal and submission for biopsy is your best bet and the best chance or a favorable recovery.

One last thing, I know that the internet is helpful in identifying lesions but even I, after 10 years of practice, will tell my clients that I am not EVER sure what one lesion or mass versus another is. I always take a conservative approach. Unfortunately, in some places on the body, especially the face, legs, rectum, around the eyes, etc.. we have to be more proactive knowing that if we wait and it gets bigger, or problematic, we may make surgery, post-op care, and cure less optimal.

Never make a diagnosis based on a picture, a likeness, or a suspicion. Make it with your vets recommendation and a thorough plan.

Here is my blog on histiocytomas. Rio's story.

Good Luck!

Krista

I did a Google image search for histiocytoma and I would guess that many of the photos shown are not histiocytomas. Which proves my point about guessing the identity a lesion by a photo.

Can you tell which lesion is which?

I wrote a blog on histicytomas, about a patient of mine named Rio. His histiocytoma photos are A and E.

Kaz is correct in that saying many histiocytomas can look like a mast cell tumor, which could be a potentially fatal mistake to make. In fact of the images above three are histicytomas, one a mast cell tumor (C), and another is a very aggressive cutaneous lymphoma (B).

Too many lesions are cancerous and the difficulty in treating them is influenced significantly on size, area of the body, how long they have been there, how fast they are growing, and the best way we can treat and hopefully cure them is to know what they are and design a plan around that diagnosis.

Every new or concerning lesion should be examined by your vet. Of particular concern to me are those that;

Grow rapidly,
Change size, shape, or consistency,
Are warm, painful, or being licked by your pet,
Are oozing, bleeding, ulcerating, or breaking through the skin
Those that make ambulating difficult, (armpits or feet).
Those that make going to the bathroom difficult, including ability to urinate, defecate, or posture to do these.
Those that are on the extremities, can be very difficult to surgically remove.
Those that are around the mouth, eyes, ears.
Those that are around the genitalia or rectum.

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