The key difference between granulation tissue and granuloma is that granulation tissue refers to new connective tissue and tiny blood vessels that form on the surface of a wound during the healing process while granuloma is an organized collection of macrophages that forms in response to persistent inflammation.
Granulation tissue is a newly formed connective tissue and microscopic blood vessels on the surface of a wound. It is a part of the wound repair process and an example of fibrovascular proliferation. In contrast, granuloma is a structure formed in response to chronic inflammation. It is an organized collection of immune cells, especially macrophages. Granulomas are often surrounded by lymphocytes.
CONTENTS
1. Overview and Key Difference
2. What is Granulation Tissue
3. What is Granuloma
4. Similarities Between Granulation Tissue and Granuloma
5. Side by Side Comparison – Granulation Tissue vs Granuloma in Tabular Form
6. Summary
What is Granulation Tissue?
Granulation tissue is the new connective tissue that forms on the surface of the wound during the wound healing process. It is a highly vascularized connective tissue. Therefore, it contains numerous tiny blood vessels. Granulation is the process of forming new connective tissue, covering the wound surface. Granulation tissue grows from the base of the wound. Moreover, it has the capacity to fill wounds of any size. Granulation tissue replaces dead or necrotic tissue.
Figure 01: Tissue Repair
During the migratory phase of wound healing, granulation tissue appears in dark pink/ light red color where it is moist, bumpy and soft to touch. It consists of a tissue matrix with different types of cells. These cells help in the formation of extracellular matrix or in immunity and vascularization. The tissue matrix of granulation tissue consists of fibroblasts. Major immune cells present in the granulation tissue include macrophages and neutrophils.
What is Granuloma?
Granuloma is an organized aggregate or collection of macrophages. It is a collection of immune cells formed during chronic inflammation. Granuloma is usually surrounded by lymphocytes. They may also be surrounded by dead materials. In addition to macrophages, granulomas may contain lymphocytes, neutrophils, eosinophils, multinucleated giant cells, fibroblasts and collagen (fibrosis). It is a tight ball-like structure.
Figure 02: Granuloma
The formation of granuloma takes place when the antigens are resistant to neutrophils and eosinophils, which are the first responder inflammatory cells. These antigens are often infectious pathogens such as bacteria or fungi or foreign substances. Therefore, granulomas develop as a result of both infectious and non-infectious diseases.
What are the Similarities Between Granulation Tissue and Granuloma?
- Both granulation tissue and granuloma prevent the spread of diseases.
- Both can be developed in response to inflammation.
- Granulation tissue and granuloma provide protection against infections.
- Both are associated with immune cells.
What is the Difference Between Granulation Tissue and Granuloma?
Granulation tissue is a highly vascularized, new connective tissue that forms on the surface of a wound as a part of the healing process. On the other hand, the granuloma is an organized collection of macrophages that forms in response to chronic inflammation. So, this is the key difference between granulation tissue and granuloma.
The below infographic tabulates more differences between granulation tissue and granuloma.
Summary – Granulation Tissue vs Granuloma
Granulation tissue is a new connective tissue and tiny blood vessels that form on the surface of a wound. It develops during the wound healing process. Granuloma is a collection of macrophages. It forms in response to chronic inflammation. Granulomas are often surrounded by lymphocytes. Granulation tissue fills the wound, replaces dead tissues and protects the wound surface. Granulomas surround and destruct foreign antigens in order to prevent the spreading of diseases. Thus, this is the summary of the difference between granulation tissue and granuloma.
Reference:
1. Alhajj, Mandy et al. “Physiology, Granulation Tissue”. Ncbi.Nlm.Nih.Gov, 2020, Available here.
2. Williams, Olivia, and Saira Fatima. “Granuloma”. Ncbi.Nlm.Nih.Gov, 2020, Available here.
Image Courtesy:
1. “417 Tissue Repair” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013 (CC BY 3.0) via Commons Wikimedia
2. “Granuloma mac” By Sanjay Mukhopadhyay – Syracuse, NY, Public Domain) via Commons Wikimedia