Cysts

Cysts are encapsulated cavities in the tissue that are filled with fluid, mucus or semi-liquid material. They can occur in various organs or directly under the skin. Cysts in dogs are usually benign, but can cause problems due to their size, location or secondary inflammation. A clear distinction from tumours or abscesses is important.

Types of cysts in dogs

• Sebaceous cysts (epidermoid cysts): caused by blocked sebaceous glands; usually small, round nodules in the skin, filled with a whitish, crumbly substance.
• Atheromas: often confused with sebaceous cysts; caused by blocked excretory ducts and contain a fatty mass.
• Sebaceous hyperplasia: nodule-like skin changes; not a true cyst, but often confused with one.
• Ovarian cysts: hormone-producing cysts on the ovaries, can lead to cycle disorders or false pregnancies.
• Prostate cysts: occur in older, intact males; can cause urinary urgency, pain or blood in the urine.
• Ganglion cysts: fluid-filled structures in the area of tendons or joints.

Causes

• Blocked excretory ducts (e.g. sebaceous glands, sweat glands)
• Hormonal influences (e.g. ovarian or prostate cysts)
• Inflammation or trauma
• Genetic predisposition (some breeds such as Boxers or Bulldogs are more susceptible)
• Age (more common in older dogs)

Symptoms

The signs depend on size and location:

• Skin cysts: small, movable nodules, sometimes with a visible opening
• Prostate cysts: problems passing urine, blood in the urine, pain
• Ovarian cysts: prolonged heat, irregular cycle, false pregnancy
• Ganglion cysts: swelling at joints or tendons, lameness

Diagnosis

To ensure a reliable assessment, veterinary medicine uses various methods:

• Clinical examination and palpation
• Fine-needle aspiration (examination of the contents under a microscope)
• Ultrasound or X-ray for internal organs
• Histopathological examination (tissue sample) to distinguish from tumours

Treatment

• Small, unproblematic skin cysts: observation, often not requiring treatment
• Inflamed or troublesome cysts: surgical removal
• Prostate and ovarian cysts: usually surgical (castration or ovariohysterectomy)
• Ganglion cysts: aspiration, removal or surgical treatment if lameness is present

Prognosis

Most cysts in dogs are benign and pose no danger. They can become problematic due to inflammation, rupture (bursting) or location in sensitive organs. A veterinary assessment is always advisable to rule out malignant tumours.