Lymphoid hyperplasia is the rapid

proliferation Proliferation may refer to: Weapons *Nuclear proliferation, the spread of nuclear weapons, material, and technology *Chemical weapon proliferation, the spread of chemical weapons, material, and technology *Missile proliferation, the spread of lon ...

of normal lymphocytic cells that resemble lymph tissue which may occur with bacterial or viral infections. The growth is termed

hyperplasia Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of Tissue (biology), organic tissue that results from ...

which may result in enlargement of various tissue including an organ, or cause a cutaneous

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...

Lymph node anatomy

lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...

is small, capsulated lymphoid organ that is present along the lymphatic system. It is composed of cortex and medulla. The cortex is also divided into outer cortex and inner cortex (also known as the paracortex). The outer cortex is composed of follicles of

B cell B cells, also known as B lymphocytes, are a type of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasm ...

s so that it is called the B-cell zone. Similarly, the inner cortex has

T cell T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell ...

s and is called the T-cell zone.

Cutaneous hyperplasia

Cutaneous Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different d ...

lymphoid lesions may be observed in follicular, granulomatous or lymphoreticular pathologic patterns. Cutaneous lymphoid hyperplasia is generally not malignant, but in rare cases an association has been observed.

Follicular hyperplasia

Follicular hyperplasia Follicular hyperplasia (FH) is a type of lymphoid hyperplasia and is classified as a lymphadenopathy, which means a disease of the lymph nodes. It is caused by a stimulation of the B cell compartment and by abnormal cell growth of secondary folli ...

is a stimulation of the B cell compartment. It is caused by an abnormal proliferation of secondary follicles and occurs principally in the cortex without broaching the lymph node capsule. The follicles are cytologically polymorphous, are often polarized, and vary in size and shape. Follicular hyperplasia must be distinguished from

follicular lymphoma Follicular lymphoma (FL) is a cancer that involves certain types of white blood cells known as lymphocytes. This cancer is a form of Non-Hodgkin Lymphoma and it originates from the uncontrolled division of specific types of B-cells ( centrocytes ...

(bcl-2 protein is expressed in neoplastic follicles, but not 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 lymph node capsule. The population of the compartment is cytologically polymorphous. Paracortical hyperplasia may be accompanied by vascular proliferation. Must be distinguished from monomorphous

T cell lymphoma T-cell lymphoma is a rare form of cancerous lymphoma affecting T-cells. Lymphoma arises mainly from the uncontrolled proliferation of lymphocytes, such as T-cells, and can become cancerous. T-cell lymphoma is categorized under Non-Hodgkin lymphom ...

Sinus hyperplasia

Sinus hyperplasia is the preferential stimulation of the histiocytic (tissues

macrophage Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that ...

) compartment. Histological features include distention or engorgement of both subcapsular and intraparenchymal sinuses by benign

histiocytes A histiocyte is a vertebrate cell that is part of the mononuclear phagocyte system (also known as the reticuloendothelial system or lymphoreticular system). The mononuclear phagocytic system is part of the organism's immune system. The histiocy ...

which may be hemo

phagocytic Phagocytosis () is the process by which a cell (biology), cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs ph ...

. Sinus hyperplasia may be associated with non-hematolymphoid malignancy. Other features include presence of white spaces and

lymphocytes A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), and ...

(large cells) within sinuses.

Complications

It is one common source of

appendicitis Appendicitis is inflammation of the Appendix (anatomy), appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, fever and anorexia (symptom), decreased appetite. However, approximately 40% of people do not have these t ...

, as it may cause an obstruction of the appendiceal lumen, resulting in the subsequent filling of the appendix with mucus, causing it to distend and internal pressure to increase. Other rare case reports describe upper airway obstruction and systemic autoimmune disease.

References

{{reflist Lymphocytic disorders