Lymphoid Hyperplasia: Definition, Causes, Anatomy, Types and Complications

It is the fast-growing proliferation of normal cells that resemble lymphatic tissue.

Lymphoid hyperplasia, also called lymphoid hypertrophy , develops in the presence of bacteria, or the growth of abnormal tissue.

Causes of lymphoid hyperplasia

The increase in lymphocytes is normally associated with the body’s immune response. Lymphoid hyperplasia is referred to by doctors as benign, reactive, or a combination of both.

Localized lymphoid hyperplasia is evidenced in appendicitis. The condition begins with an obstruction between the appendix and the intestine. The obstruction can be caused by trapped stools, excess mucus, or lymphatic swelling.

Then the bacteria that pass through the intestine can invade the wall of the appendix, activating the immune system. Symptoms that the immune system initiated a response are inflammation and discomfort.

Lymph node anatomy

A lymph node is a small, capsulated lymphoid organ that is present throughout the lymphatic system.

It is made up of cortex and medulla. The cortex is also divided into the outer cortex and the inner cortex (also known as the paracortex). The outer cortex is made up of B-cell follicles, so it is called the B-cell zone. Similarly, the inner cortex has T cells and is called the T-cell zone.


Follicular hyperplasia

Follicular hyperplasia is a stimulation of the B cell compartment.

It is caused by an abnormal proliferation of secondary follicles and occurs mainly in the cerebral cortex without opening the capsule of the lymph nodes.

Follicles are polymorphic cytomorphs, are often polarized, and vary in size and shape. Follicular hyperplasia must be distinguished from follicular lymphoma (bcl-2 protein is expressed in neoplastic follicles, but not in reactive follicles).

Paracortical hyperplasia

Paracortical hyperplasia is the preferential stimulation of the T-cell compartment. It is caused by an abnormal expansion of the interfollicular zones, but is confined within the capsule of the lymph nodes.

The compartment population is cytologically polymorphic. Paracortical hyperplasia can be accompanied by vascular proliferation. It must be distinguished from monomorphic T-cell lymphoma.

Sinus hyperplasia

Sinus hyperplasia is the preferential stimulation of the histiocytic compartment ( macrophage tissue ).

Histologic features include distention or congestion of the subscapular and inatraparenchymal sinuses by benign histiocytes that may be heme phagocytic.

Sinus hyperplasia may be associated with non-hematolymphoid malignancy. Other features include the presence of white spaces and lymphocytes (large cells) within the sinuses.


It is a common source of appendicitis , as it can cause an obstruction of the appendicular lumen, resulting in subsequent filling of the appendix with mucus, causing it to distend and internal pressure to increase.