What is the Difference Between Nodule and Polyp

The main difference between nodule and polyp is that a nodule is a calluses-like growth whereas a polyp is a blister-like, large growth. Furthermore, nodules are rarely vascularized while polyps are more vascularized.

Nodule and polyp are two types of most common, non-cancerous lesions of the vocal folds. Vocal fold nodules are also known as Singer’s Nodes or Screamer’s Nodes and they are present on both vocal folds, facing each other. On the other hand, vocal fold polyps occur on only one side of the vocal folds.

Key Areas Covered

1. What is a Nodule
     – Definition, Structure, Significance
2. What is a Polyp
     – Definition, Structure, Significance
3. What are the Similarities Between Nodule and Polyp
     – Outline of Common Features
4. What is the Difference Between Nodule and Polyp
     – Comparison of Key Differences

Key Terms

Mucous Membrane, Nodule, Polyp, Vocal Fold Lesions

What is a Nodule

A nodule is a small swelling that is abnormal. Generally, the diameter of a nodule is more than 0.5 cm. It is an elevated area that may be solid or filled up with fluid. Also, nodules are painless and benign. Vocal fold nodules, thyroid nodules, and rheumatoid nodules are some examples of nodules.

Figure 1: Vocal Fold Nodule

Furthermore, vocal fold nodules occur on both sides of the vocal folds, facing each other. Generally, they are located at the middle of the membranous part of the vocal fold. Vocal fold nodules are a type of lesions of vocal folds known as “calluses of the vocal fold”. Therefore, they disappear with the termination of the trauma of the vocal folds. When vocal fold nodules are observed under the microscope, they consist of a thickened surface layer of the vocal folds and the superficial lamina propria. Moreover, the two types of vocal fold nodules are the soft or young nodules that arise due to the misuse of voice and the hard or the old vocal fold nodules that arise due to age.

What is Polyp

A polyp is a type of abnormal tissue projection from a mucous membrane. Generally, polyps occur in the colon, stomach, nose, ear, sinuses, etc. Also, some polyps occur in the cervix, vocal folds, and small intestine. The two main types of polyps are sessile and pedunculated polyps. The sessile polyps lack a stalk, which connects the polyp to the surface while pedunculated polyps have a stalk, attaching the polyp to the surface. However, both types of polyps are benign, but some may premalignant.

Figure 2: Vocal Fold Polyp

Moreover, single vocal fold polyp occurs on one side of the vocal folds. Therefore, vocal fold polyps are also a type of vocal fold lesions. The main distinguishing feature of vocal fold polyps is their highly vascularized nature. Hence, they show a reddish appearance under the microscope. In addition, vocal fold polyps can be larger than nodules of vocal folds. The overuse or misuse of the vocal folds result in polyps as well. However, some vocal fold polyps are exclusively associated with smoking.

Similarities Between Nodule and Polyp

• Nodule and polyp are the two most common types of lesions of vocal folds.
• They are abnormal growths that occur within or along with the covering of the vocal fold.
• Generally, both are non-cancerous.
• But, they are the reasons for most common voice problems.

Difference Between Nodule and Polyp

Definition

A nodule refers to a small swelling or aggregation of cells in the body, especially an abnormal one, while a polyp refers to a small growth, usually benign and with a stalk, protruding from a mucous membrane. Thus, this is the main difference between nodule and polyp.

Examples 

Vocal fold nodules, thyroid nodules, and rheumatoid nodules are some examples of nodules while polyps occur in the colon, stomach, nose, ear, sinuses, etc. 

Types

Soft nodules and hard nodules are the two types of vocal fold nodules while sessile polyps and pedunculated polyps are the two types of polyps.

Shape in Vocal Folds

Another difference between nodule and polyp is that nodules in the vocal folds are calluses-like growth while polyps are blister-like growth.

Size

Moreover, nodules are small in size while polyps are comparatively large. This is another difference between nodule and polyp.

Occurrence in Vocal Folds

One other difference between nodule and polyp is that nodules occur in both vocal folds, facing each other while only one polyp occurs on one side of the vocal folds at a time.

Vascularization

Furthermore, nodules are not vascularized while polyps are more vascularized.

Conclusion

A nodule is a smaller swelling that is calluses-like. Nodules occur on both vocal folds, facing each other. In comparison, polyps are comparatively large abnormal growths that are blister-like. They occur alone on one side of the vocal folds. Both nodule and polyp are two types of abnormal growths on the vocal folds known as vocal fold lesions, resulting in voice problems. However, the main difference between nodule and polyp is structure and influence.

Reference:

1. “Vocal Nodules Symptoms, Treatment & More.” Cleveland Clinic, Available Here.

Image Courtesy:

1. “Laryngeal nodule (1)” By No machine-readable author or source provided. Own work assumed (based on copyright claims). (CC BY-SA 3.0) via Commons Wikimedia  
2. “Stimmbandpolyp1” By Welleschik – Own work (CC BY-SA 3.0) via Commons Wikimedia