Liver Tumors (Mature Age Related) in Dogs

Hepatic nodular hyperplasia is a common type of age-related benign tumor located in the liver. Many dogs begin to develop the hepatic nodules around ten years old, and most dogs have developed them by the time they reach fourteen. The nodules can form singly or in small groups. Unlike other tumors that may be found in the liver, these nodules are generally asymptomatic and have a very low incidence of rupture and no potential for malignancy. Because of the similarity of hepatic nodular hyperplasia to more serious tumors, a biopsy of the mass or masses may be required.

Hepatic nodular hyperplasia is an asymptomatic benign tumor of the liver that occurs in older dogs, usually over the age of ten.

There are often no generally observable symptoms at all with hepatic nodular hyperplasia, and they are often located either during a normal autopsy or during x-rays or ultrasounds being given for other reasons. Indicators that your pet has hepatic nodular hyperplasia can include:

• Advanced age 
• Increased liver enzyme activity

 If the tumors are poorly placed, of a different type, or if there is concurrent damage to the liver you may see these additional symptoms:

•  Abdominal pain 
• Abdominal swelling
• Diarrhea
• Disorientation
• Increased need to urinate
• Increased thirst
• Jaundice
• Lethargy
• Loss of appetite
• Nausea or vomiting
• Seizures
• Stumbling
• Unexplained weight loss
• Weakness

   Types

 There are several types of tumors and growths that can occur in the liver, some more damaging than others. Other tumors or conditions that may be diagnosed by the biopsy can include:

• Bile duct carcinoma
• Carcinoid tumor
• Chronic hepatitis
• Hemangioma
• Hepatic cysts
• Hepatocellular adenoma
• Hepatocellular carcinoma
• Leiomyoma
• Mesenchymal tumor (sarcoma)
• Neoplasia

The most common cause of hepatic nodular hyperplasia is simply advanced age. Although nodules are occasionally found in dogs as young as six to eight years old, they become much more common in dogs over the age of ten and are almost always found in the livers of dogs over the age of fourteen. There are some indications that liver disease or trauma to the liver may speed the formation of the tumors.

Hepatic nodular hyperplasia lesions viewed by ultrasound are visually difficult to differentiate from more serious disorders such as hepatocellular carcinomas, chronic hepatitis, or neoplasia. 

Your veterinarian may recommend a biopsy in order to determine what kind of growth it is. The biopsy can reveal information regarding whether or not the mass is malignant.  

The two types of biopsies that may be considered include:

• Needle Biopsy- A thin needle is inserted into the tissue to remove a core sample. This procedure is slightly less invasive however only a very small sample is taken to be tested. 
• Wedge Biopsy- The tumor or lesion is removed with a wedge of the surrounding tissue. Although this form of biopsy is more invasive it may give a clearer picture of the overall health of the liver. This is the type of biopsy most commonly recommended, especially if other symptoms of liver disease are present. 

Your veterinarian may choose to do the biopsy either with open surgery or laparoscopically.

Once conclusively diagnosed as hepatic nodular hyperplasia, further treatment is generally not indicated. These extremely common tumors are benign and have a very low risk of developing malignancy or of rupturing. It is exceptionally uncommon for complications to arise. If complications do arise from rupture or placement within the liver, the tumor will have to be removed or resectioned to allow for proper function of the liver. 

Generally speaking, there will be very little difference in treatment and management for your dog before and after a diagnosis of hepatic nodular hyperplasia. The nodules generally do not have a large effect on liver function and do not interfere with quality of life. Your veterinarian will want to monitor the growths as well as blood chemistry and liver enzymes on a regular basis. This is in order to prevent future complications and to ensure that if less benign growths develop they are spotted early. If your pet underwent a biopsy in order to reach a diagnosis it is important to make sure that any incision sites are kept clean and dry until any stitches heal.