What is the Difference Between Sessile and Pedunculated

The main difference between sessile and pedunculated is that sessile refers to attachment to a surface without a stalk whereas pedunculated refers to attachment to a surface by a narrow elongated stalk known as a peduncle. Furthermore, sessile polyps are flat while pedunculated polyps are mushroom-like.

Sessile and pedunculated are the two basic shapes of colon polyps classified based on the presence of a peduncle.

Key Areas Covered

1. What is Sessile
     – Definition, Attachment, Significance
2. What is Pedunculated
     – Definition, Attachment, Significance
3. What are the Similarities Between Sessile and Pedunculated
     – Outline of Common Features
4. What is the Difference Between Sessile and Pedunculated
     – Comparison of Key Differences

Key Terms

Colon Polyps, Peduncle, Pedunculated, Sessile, Shape

What is Sessile

Sessile is the state of an anatomical structure of an animal or plant, being attached to the surface without a stalk. The main characteristic feature of sessile structures is that they are flat. The term ‘sessile’ is used to describe polyps. Generally, polyps are small, abnormal growths of a mucous membrane. They commonly occur in the colon, stomach, nose, sinuses, uterus, urinary bladder, etc. However, colon polyps are more frequent than other types of polyps.

Figure 1: Sessile Polyp

Also, 85% of the colon polyps are sessile. Furthermore, due to the flat nature of a sessile polyp, this type of polyps are difficult to diagnose. Therefore, they have a high risk to become cancerous. Though small sessile polyps can be easily snared, large sessile polyps have to be removed in pieces.

What is Pedunculated

Pedunculated is the state of being attached to the surface by a long, thin stalk. Generally, this stalk is known as the peduncle. The term ‘pedunculated’ is used to describe the shape of polyps as well. The main characteristic feature of this type of polyps is their mushroom-like shape. Usually, 13% of colon polyps are pedunculated. More importantly, the pedunculated polyps are easy to diagnose as they are raised out from the surface. Also, they are easy to remove in one piece from their stalk. Therefore, the risk of becoming cancerous is low in pedunculated polyps.

Figure 2: Pedunculated Polyp

Sessile vs Pedunculated Oaks

Furthermore, both terms sessile and pedunculated are used to describe two species of oak. The sessile oak (Quercus petraea) is also known as Cornish oak or durmast oak. On the contrary, the pedunculate oak (Quercus robur) is also known as European oak or English oak. Both oak varieties are native to Europe. 

Figure 3: Sessile and Pedunculate Oak

The main difference between sessile oak and pedunculate oak is that sessile oak does not contain auricles at the base of the leaf while pedunculate oak contains two auricles at the base of the leaf before connecting to the petiole.

Similarities Between Sessile and Pedunculated

• Sessile and pedunculated are the two shapes of colon polyps.
• The four types of colon polyps are inflammatory colon polyps, hyperplastic polyps, adenomatous polyps, and villous adenoma.
• The shape of the colon polyp is important to determine its potential risk for cancer and the type of treatment.

Difference Between Sessile and Pedunculated

Definition

Sessile refers to a plant or animal structure attached directly by its base without a stalk or peduncle while pedunculated refers to a plant or animal structure supported by a peduncle. Thus, this is the main difference between sessile and pedunculated.

Type of Attachment

Also, another difference between sessile and pedunculated is that the sessile structures do not attach to the surface by a stalk while pedunculated structures attach to the surface by a stalk.

Shape of Colon Polyps

Furthermore, sessile polyps are flat while pedunculated polyps are mushroom-like. Hence, this is another major difference between sessile and pedunculated.

Diagnosis

Moreover, sessile polyps are difficult to diagnose while pedunculated polyps are easy to diagnose as they are raised from the surface.

Risk of Cancer

Besides, one other important difference between sessile and pedunculated is that while sessile polyps can be cancerous as they are difficult to diagnose, pedunculated polyps have a low risk of being cancerous.

Conclusion

Sessile is the state of not being attached to the surface by a stalk. In contrast, pedunculated is the state of being attached to the surface by a stalk called peduncle. Also, sessile anatomical structures are generally flat while pedunculated structures are mushroom-like. Usually, the two terms are used to describe the two shapes of polyps in the body. Sessile polyps are cancerous as they are difficult to diagnose while pedunculated polyps are less cancerous as they are easy to diagnose and remove. However, the main difference between sessile and pedunculated is the presence of a stalk and the shape.

References:

1. Dixon, Suzanne. “The Types of Colon Polyps and What You Should Know About Them.” Very well Health, Verywellhealth, 3 Dec. 2018, Available Here

Image Courtesy:

1. “Sessile serrated adenoma endo” By User:Samir (CC BY-SA 3.0) via Commons Wikimedia  
2. “Polyp” By Original uploader was Rsabbatini at en.wikipediaLater version(s) were uploaded by Kd4ttc at en.wikipedia. – Transfered from en.wikipedia (CC BY 2.5) via Commons Wikimedia  
3. “Quercus petraea 02” (CC BY-SA 2.5) via Commons Wikimedia  
4. “Quercus robur” (CC BY-SA 3.0) via Commons Wikimedia