Mallory-Denk Bodies: Definition

Reviewed by Pathologists on:
January 6, 2026

Mallory-Denk bodies are abnormal clumps of protein found inside liver cells called hepatocytes. These protein clumps form when liver cells are injured and can no longer process or dispose of specific structural proteins normally.

Mallory–Denk bodies are not a disease by themselves. Instead, they are a microscopic finding that tells pathologists the liver has been under stress or damaged over time.

What are hepatocytes?

Hepatocytes are the primary working cells of the liver. They perform many essential tasks, including producing bile, processing nutrients, filtering toxins, and making proteins needed by the body. When hepatocytes are repeatedly or severely injured, their internal structure can become disorganized, leading to the formation of Mallory–Denk bodies.

What are Mallory–Denk bodies made of?

Mallory–Denk bodies are made up of damaged structural proteins that normally help maintain the shape and stability of liver cells. These proteins, called keratins, become misfolded and clump together instead of being broken down and removed. Under the microscope, these clumps appear as dense, irregular material within the cytoplasm (the body of the cell).

What do Mallory–Denk bodies look like under the microscope?

When viewed under the microscope, Mallory–Denk bodies appear as rope-like or tangled pink material inside hepatocytes. They often distort the cell’s normal shape and are typically seen in liver tissue that also shows signs of inflammation or injury.

Pathologists can identify Mallory–Denk bodies using routine stains and may confirm them with special stains when needed.

What conditions are associated with Mallory–Denk bodies?

Mallory–Denk bodies are seen in several liver diseases, especially those involving long-standing injury.

Common associated conditions include:

• Alcohol-related liver disease, where repeated alcohol exposure damages liver cells.

• Non-alcoholic steatohepatitis (NASH), a form of fatty liver disease linked to obesity, diabetes, and metabolic syndrome.

• Chronic cholestatic liver diseases, where bile flow is impaired.

• Wilson disease, a genetic disorder involving copper buildup in the liver.

• Specific drug-related or toxic liver injuries.

The presence of Mallory–Denk bodies helps pathologists recognize patterns of liver injury but does not point to a single specific diagnosis.

Why might Mallory–Denk bodies be mentioned in a pathology report?

Mallory–Denk bodies may be described in a pathology report when a liver biopsy shows evidence of ongoing or past liver cell injury. Their presence supports a diagnosis of liver disease related to chronic stress, inflammation, or toxic exposure.

Pathologists interpret Mallory–Denk bodies together with other findings, such as steatosis, inflammation, fibrosis (scarring), and cholestasis, to determine the underlying cause of liver damage.

Are Mallory–Denk bodies dangerous?

Mallory–Denk bodies themselves do not cause symptoms and are not harmful on their own. However, they are a sign that liver cells have been injured, often repeatedly.

The importance of this finding depends on the liver’s overall condition and the underlying disease. Treating the underlying cause of liver injury may reduce further damage, even if existing Mallory–Denk bodies remain visible in the tissue.

Questions to ask your doctor

• Why were Mallory–Denk bodies found in my liver biopsy?

• What type of liver injury do they suggest in my case?

• Are these findings related to alcohol use, fatty liver disease, or another condition?

• Does this mean my liver disease is severe or long-standing?

• What steps can I take to protect my liver moving forward?