Leiomyoma or intestinal/stomach tumours in dogs

Leiomyoma is the scientific name for a type of tumour that can grow within a dog’s stomach or intestines on the smooth side muscles within the digestive system. Tumours of this type are slow to develop, often benign, and limited in terms of their harm and spread, but they can cause secondary complications if they block the digestive tract or occlude other organs.

Leiomyomas tend to affect mature and senior dogs rather than their younger counterparts, and they can affect dogs of any breed or type.

In this article we will look at leiomyomas of the stomach or intestine in dogs and explain what they are, how they present, and what can be done about them. Read on to learn more.

What sort of dogs might develop leiomyoma?

Leiomyoma is not a breed-specific health condition, and there is not thought to be a hereditary or conformation problem that causes the condition to develop in any given dog. Whilst leiomyomas are not one of the most common forms of tumours dogs can develop, they affect males and females equally commonly, and can develop in both neutered and unneutered dogs alike.

One factor that most diagnoses of leiomyoma have in common is that they tend to occur in older dogs, with six or seven years of age being the lowest usual age of onset. This means that owners of mature and senior dogs should be particularly vigilant to the potential symptoms that can accompany leiomyomas.

What are the symptoms of a leiomyoma?

Leiomyomas are slow-growing tumours that can develop in a dog’s stomach or intestines, and the symptoms that any given dog displays will vary depending on where the tumour grows, how advanced it is, and your individual dog themselves.

Leiomyomas that grow in a dog’s stomach form on the stomach wall, and may present with no symptoms at all. This means that a stomach leiomyoma might only be discovered by chance. However, vomiting is one of the most common and generalised symptoms of a stomach leiomyoma in dogs, but even reaching a diagnosis from this symptom alone takes a reasonable amount of detective work, as there are so many other health conditions that also lead to vomiting.

If the leiomyoma grows in the dog’s small intestine, this tends to result in more symptoms than if the tumour grows in the dog’ stomach, but again these are often quite generalised and can be hard to pinpoint to the root cause.

Small intestine leiomyomas may again cause vomiting, as well as potentially excess gas, and noisy digestive sounds like a rumbling stomach. If you palpate your dog’s abdomen you may be able to feel a mass, or parts of the dog’s small intestine itself may feel inflamed or painful.

Some dogs will also lose weight and condition as the disease progresses too.

Leiomyomas that develop in the dog’s large intestine tends to produce more precise symptoms, but again these are often subtle and because they happen internally, can be hard to pinpoint. Dogs with a leiomyoma in the large intestines might have fresh blood in their stools, or problems passing stools that can manifest as straining or constipation, and being unable to toilet normally.

A large intestine leiomyoma can also cause a rectal prolapse which will appear quite obvious, and a mass may be present within the dog’s rectum that might be evident upon palpation.

How is leiomyoma in dogs diagnosed?

Formal diagnosis a leiomyoma can be challenging given the range of symptoms that can occur, and how generalised they can be. Your vet will need to consider a number of potential causes and rule out those that aren’t relevant and they will work hard to do this as quickly as possible, but it may still take some time.

Your vet will examine your dog and their health history in order to pinpoint the area that is affected, before running further tests and exams to get to the root of the issue. Blood panels and urinalysis will usually be performed, and your vet may also wish to perform an ultrasound to identify the thickening of the wall muscle of the stomach or intestine that indicates the presence of a tumour.

X-rays and imaging techniques of other kinds might be required too, such as an endoscopic camera to get a clear look at what is going on internally.

When your vet finds the tumour itself, they will probably take a biopsy of it to reach a firm diagnosis and so, determine the best way to proceed from there.

Can leiomyomas be treated?

Leiomyomas are usually treated surgically, which is generally highly successful because such tumours are often (but not always) benign, slow growing, and limited in terms of their spread. Successful surgical removal of the tumour and a good recovery on the part of the dog after surgery generally resolves the issues and restores the dog to good health.

However, if your dog is not a viable candidate for surgery or if your vet determines that the leiomyoma is not operable, other options may be considered, including palliative care and support to maintain the dog’s quality of life. Because many leiomyomas are benign and also because leiomyomas tend to be slow in development, a decision may be made to avoid surgery on an elderly dog who is likely to live out their natural life without the tumour causing them a major problem.