Pyogenic granuloma

What is a pyogenic granuloma?

A pyogenic granuloma is a common non-cancerous type of tumour made up of blood vessels and inflammatory cells. The tumour often appears suddenly and grows very quickly at first only to decrease in size gradually slowly over several days or weeks. Without treatment, some tumours will disappear entirely. Another name for this tumour is lobular capillary hemangioma.

Although this kind of tumour can start anywhere, the most common locations include the nose, lips and mouth, and skin. When examined without a microscope, the tumour is usually round, and the surface may appear bright red. Some tumours are painful, and the tumour may bleed when touched.

pyogenic granuloma

What causes a pyogenic granuloma?

Most tumours develop following a minor injury such as a scratch or burn. This is especially true for tumours that start inside the mouth (oral cavity) or nose (nasal cavity). However, for some patients, no cause can be identified. Pregnant women are more susceptible to developing these types of tumours, especially on the lips. When this tumour develops in a pregnant woman it is given the name granuloma gravidarum.

How do pathologists make this diagnosis?

The diagnosis is usually made after the entire tumour is removed and sent to a pathologist to examine under the microscope. When examined under the microscope, the cells on the outer surface of the tissue are damaged or lost. Pathologists call this an ulcer. Further down, the tumour is made up of many small and medium-sized blood vessels. The smaller vessels tend to surround the medium-sized vessels in pattern pathologists describe as lobular.

The tissue surrounding the blood vessels is made up of fluid and specialized inflammatory cells including neutrophils, plasma cells, and lymphocytes. The combination of blood vessels and inflammatory cells within a pyogenic granuloma makes the tumour look similar to granulation tissue, a type of tissue that forms after an injury. For this reason, many doctors consider pyogenic granuloma to be a tumour-like reaction to an earlier injury.

by Jason Wasserman MD PhD FRCPC (updated August 22, 2021)
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