Angiokeratoma circumscriptum naeviforme (ACN) is a rare skin disorder that is characterized by the development of multiple red or blue-black papules or plaques on the skin. These lesions are caused by the proliferation of small blood vessels (angiokeratomas) and the accumulation of keratin in the epidermis. ACN is also known as angiokeratoma corporis naeviforme, naevus vascularis papillomatosus, and nevus angiokeratoma.
There are several types of ACN, each with its own set of clinical features, causes, and treatment options. In this article, we will provide an overview of the definitions and types of ACN.
- Non-hereditary (sporadic) ACN: This is the most common type of ACN and occurs in individuals with no family history of the disorder. It usually presents as solitary or multiple papules or plaques on the lower extremities, although it can occur anywhere on the body. The lesions are usually asymptomatic but may bleed or itch. The cause of sporadic ACN is not well understood, but it is thought to be related to a genetic mutation or abnormal blood vessel development.
- Hereditary ACN: This is a rare form of ACN that is inherited in an autosomal dominant pattern. It usually presents at birth or in early childhood as multiple reddish-brown or blue-black papules or plaques on the trunk, extremities, and face. The lesions may be raised or flat and can coalesce to form large areas of discoloration. Hereditary ACN is caused by a mutation in the angiokeratin-1 gene.
- Fordyce angiokeratoma: This is a type of ACN that is characterized by solitary or multiple papules on the scrotum or vulva. The lesions are usually asymptomatic but may cause discomfort or embarrassment. Fordyce angiokeratoma is not considered a true ACN because it does not involve the proliferation of blood vessels.
- Mibelli angiokeratoma: This is a type of ACN that presents as small, red to purple papules on the hands and feet. The lesions may be painful and may cause itching or burning. Mibelli angiokeratoma is thought to be caused by abnormal blood vessel development.
- Angiokeratoma circumscriptum: This is a type of ACN that presents as a solitary or multiple plaques on the trunk, extremities, or head and neck. The lesions are usually asymptomatic but may be painful or cause itching. Angiokeratoma circumscriptum is thought to be caused by abnormal blood vessel development.
Possible causes of ACN and their underlying mechanisms in detail.
Genetic mutations have been reported in some cases of ACN, suggesting that the condition may be inherited. These mutations can affect the development and function of blood vessels, leading to the formation of the characteristic papules. However, the inheritance pattern of ACN is not well understood, and more research is needed to clarify its genetic basis.
- Hormonal factors
Hormonal changes, such as those that occur during puberty, pregnancy, or menopause, can affect blood vessel development and contribute to the development of ACN. In some cases, ACN has been reported to improve or resolve after hormonal therapy or surgical removal of the ovaries.
Trauma to the skin, such as friction or pressure, can cause damage to blood vessels and promote the development of ACN. This may explain why ACN is commonly found on the lower limbs, where pressure and friction are more frequent.
Infection with certain viruses, bacteria, or fungi can trigger an immune response that leads to the formation of ACN. For example, human papillomavirus (HPV) has been implicated in the development of some cases of ACN.
- Autoimmune diseases
Autoimmune diseases, such as lupus, rheumatoid arthritis, and scleroderma, can affect blood vessel function and promote the development of ACN.
- Chronic venous insufficiency
Chronic venous insufficiency is a condition in which the valves in the veins of the legs are damaged or weak, leading to poor blood flow and the formation of varicose veins. This condition can also contribute to the development of ACN.
- Arteriovenous malformation
Arteriovenous malformation (AVM) is a congenital condition in which the blood vessels in a particular area of the body are abnormally formed and connected. This can cause blood to flow too quickly through the affected area, leading to the formation of ACN.
- Lymphatic malformation
Lymphatic malformation is a rare congenital condition in which the lymphatic vessels are abnormally formed and do not function properly. This can lead to the accumulation of lymphatic fluid in the affected area, causing swelling and the development of ACN.
- Vascular malformation
Vascular malformation is a group of rare congenital conditions that affect the blood vessels. These conditions can cause abnormal blood vessel growth and function, leading to the formation of ACN.
- Sturge-Weber syndrome
Sturge-Weber syndrome is a rare congenital disorder that affects the development of blood vessels in the brain and face. This syndrome can also cause the formation of ACN on the skin.
- Klippel-Trenaunay syndrome
Klippel-Trenaunay syndrome is a rare congenital disorder characterized by the abnormal development of blood vessels, soft tissue, and bone in one or more limbs. This syndrome can also cause the formation of ACN on the affected limb.
- Maffucci syndrome
Maffucci syndrome is a rare congenital disorder that affects bone and soft tissue development. This syndrome can also cause the formation of AC
Symptoms of ACN in detail.
- Multiple angiokeratomas: The hallmark symptom of ACN is the development of multiple angiokeratomas in a nevus-like distribution on the skin. These lesions are typically small, raised, red or purple papules that may be slightly elevated or flat.
- Localized distribution: The lesions are usually confined to a single area of the body, such as the lower extremities, buttocks, or genital area. Rarely, the lesions can occur in multiple areas.
- Darkening of lesions: Over time, the lesions may become darker in color and more prominent.
- Thickening of lesions: The lesions may thicken and become more raised over time, leading to a rough, wart-like appearance.
- Itching: Some individuals with ACN may experience itching or irritation of the affected skin.
- Pain: Rarely, the lesions may be painful, particularly if they are located in areas of friction or pressure.
- Ulceration: In rare cases, the lesions may become ulcerated, which can be painful and increase the risk of infection.
- Bleeding: The lesions may bleed if they are scratched or traumatized, but this is uncommon.
- Increased sensitivity to temperature: Some individuals with ACN may experience increased sensitivity to hot or cold temperatures in the affected area.
- Hyperhidrosis: Hyperhidrosis, or excessive sweating, may occur in the area affected by ACN.
- Discoloration of surrounding skin: The skin surrounding the lesions may become darker or lighter in color than the surrounding skin.
- Distorted skin texture: The skin surrounding the lesions may become thickened or rough in texture.
- Hair loss: The lesions may cause hair loss in the affected area.
- Nail abnormalities: Rarely, the lesions may cause nail abnormalities, such as ridges or thickening.
- Lesions may spread: While ACN is typically confined to a single area of the body, in rare cases, the lesions may spread to other areas.
- Age of onset: ACN typically develops in childhood or adolescence, although it can develop at any age.
- More common in females: ACN is more common in females than males.
- Family history: ACN may be inherited in an autosomal dominant pattern, meaning that a family history of the condition increases the risk of developing it.
- Associated conditions: ACN may be associated with other vascular malformations, such as lymphangioma circumscriptum or verrucous hemangioma.
Diagnosis of ACN can be challenging because it is a rare condition and the lesions can be mistaken for other skin conditions such as angiokeratoma of Fordyce, cherry angiomas, and vascular malformations. Therefore, a thorough evaluation of the patient’s medical history and physical examination is essential for accurate diagnosis. In addition, several tests may be recommended to confirm the diagnosis and rule out other conditions. Here are the most common diagnosis and tests for angiokeratoma circumscriptum naeviforme:
- Medical history: A detailed medical history is the first step in diagnosing ACN. This includes a review of the patient’s personal and family history of skin conditions, including any previous treatment they may have received.
- Physical examination: A complete physical examination is performed to evaluate the extent and distribution of the skin lesions. The lesions of ACN are typically small, red to purple papules or nodules, with a rough and scaly texture.
- Dermoscopy: Dermoscopy is a non-invasive imaging technique that uses a special handheld device to magnify the skin surface. It can help distinguish ACN from other skin conditions and may reveal characteristic features such as a well-defined border and a cobblestone-like surface.
- Skin biopsy: A skin biopsy involves taking a small sample of the affected skin and examining it under a microscope. This test can confirm the diagnosis of ACN and rule out other skin conditions such as melanoma, basal cell carcinoma, or squamous cell carcinoma.
- Immunohistochemistry: Immunohistochemistry is a laboratory test that uses special antibodies to identify specific proteins in skin tissue samples. This test can help distinguish ACN from other skin conditions and may reveal characteristic markers such as CD34 or D2-40.
- Electron microscopy: Electron microscopy is a laboratory test that uses an electron microscope to examine the structure of skin cells and tissues at a very high magnification. It can help reveal characteristic features of ACN such as dilated blood vessels and thickened skin layers.
- Genetic testing: ACN is believed to have a genetic component, and genetic testing may be recommended to identify any mutations or abnormalities that may be contributing to the condition.
- Blood tests: Blood tests can help rule out other conditions that may be causing the skin lesions, such as infections or autoimmune disorders.
- Urine tests: Urine tests can help evaluate kidney function, which may be affected in some cases of ACN.
- Electrocardiogram (ECG): An ECG is a non-invasive test that records the electrical activity of the heart. This test may be recommended to evaluate cardiac function in patients with ACN, as some cases may be associated with heart abnormalities.
- Echocardiogram: An echocardiogram is an imaging test that uses sound waves to produce images of the heart. This test may be recommended to evaluate cardiac function in patients with ACN.
- Magnetic resonance imaging (MRI): MRI is a non-invasive imaging technique that uses a magnetic field and radio waves to produce detailed images of the body. It may be recommended to evaluate the extent and distribution of skin lesions and to identify any underlying structural abnormalities.
- Computed tomography (CT) scan: CT scan is a non-invasive imaging technique that uses X-rays to produce
Different treatment options for angiokeratoma circumscriptum naeviforme in detail.
- Observation – In some cases, observation may be recommended as a first-line treatment for ACN. This involves monitoring the condition over time to see if it worsens or causes any significant symptoms. Observation may be recommended for individuals with mild or asymptomatic ACN.
- Laser Therapy – Laser therapy is a common treatment option for ACN. It involves using a high-intensity laser to target and destroy the blood vessels that cause the papules. Laser therapy can be effective in reducing the size and appearance of the papules and may be recommended for individuals with moderate to severe ACN.
- Cryotherapy – Cryotherapy involves freezing the papules with liquid nitrogen, causing them to shrink or disappear. Cryotherapy can be an effective treatment option for small or isolated papules and may be recommended for individuals with mild to moderate ACN.
- Electrocautery – Electrocautery is a medical procedure that uses an electrical current to heat and destroy the papules. This can be an effective treatment option for smaller papules and may be recommended for individuals with mild to moderate ACN.
- Excision – Excision involves surgically removing the papules from the skin. This can be an effective treatment option for larger or more severe papules and may be recommended for individuals with moderate to severe ACN.
- Topical Creams – Topical creams, such as retinoids or corticosteroids, can be used to reduce inflammation and improve the appearance of the papules. Topical creams may be recommended for individuals with mild to moderate ACN.
- Photodynamic Therapy – Photodynamic therapy involves using a photosensitizing agent and a special light to destroy the blood vessels that cause the papules. Photodynamic therapy can be an effective treatment option for larger or more severe papules and may be recommended for individuals with moderate to severe ACN.
- Radiotherapy – Radiotherapy involves using high-energy radiation to destroy the blood vessels that cause the papules. Radiotherapy can be an effective treatment option for larger or more severe papules and may be recommended for individuals with moderate to severe ACN.
- Mohs Micrographic Surgery – Mohs micrographic surgery involves surgically removing the papules from the skin while preserving as much healthy tissue as possible. This can be an effective treatment option for larger or more severe papules and may be recommended for individuals with moderate to severe ACN.
- Sclerotherapy – Sclerotherapy involves injecting a solution into the blood vessels that cause the papules, causing them to shrink or disappear. Sclerotherapy can be an effective treatment option for smaller or isolated papules and may be recommended for individuals with mild to moderate ACN.
- Chemical Peels – Chemical peels involve applying a solution to the skin that causes the outer layers to peel away, revealing fresh, healthy skin underneath. Chemical peels can be an effective treatment option for improving the appearance of the papules and may be recommended for individuals with mild to moderate ACN.
- Electrodessication: Electrodessication uses a high-frequency electrical current to burn off the affected tissue. This method can be effective for smaller lesions but may also cause scarring.
- Laser therapy: Various types of lasers have been used to treat ACN, including pulsed dye lasers and CO2 lasers. Laser therapy may be effective for treating larger lesions and may minimize scarring.
- Topical retinoids: Topical retinoids, such as tretinoin or adapalene, can be used to reduce the appearance of ACN lesions by promoting cell turnover and reducing keratinization. These medications may take several weeks or months to show results.
- Topical corticosteroids: Topical corticosteroids can reduce inflammation and redness associated with ACN, but they do not typically affect the underlying blood vessels.
- Topical calcineurin inhibitors: Topical calcineurin inhibitors, such as tacrolimus or pimecrolimus, can be used to reduce inflammation and may be effective for treating smaller lesions.
- Topical imiquimod: Imiquimod is an immune response modifier that can be used topically to stimulate the immune system and reduce the appearance of ACN lesions.
- Oral retinoids: Oral retinoids, such as isotretinoin, can be used to reduce the appearance of ACN lesions by promoting cell turnover and reducing keratinization. However, these medications can have significant side effects and should only be used under close medical supervision.
- Oral antibiotics: Oral antibiotics may be used to treat secondary infections or to reduce inflammation associated with ACN lesions.
- Photodynamic therapy: Photodynamic therapy involves the use of a photosensitizing agent and a light source to destroy abnormal cells. This method may be effective for treating larger lesions but can cause significant inflammation and scarring.
- Sclerotherapy: Sclerotherapy involves the injection of a sclerosing agent, such as sodium tetradecyl sulfate, into the affected blood vessels to cause them to collapse. This method may be effective for treating larger lesions but can cause scarring.
- Laser-assisted drug delivery: Laser-assisted drug delivery involves the use of a laser to enhance the penetration of topical medications into the skin. This method may be effective for treating smaller lesions.
- Radiofrequency ablation: Radiofrequency ablation involves the use of a high-frequency electrical current to heat and destroy the affected tissue. This method may be effective for treating larger lesions but can cause scarring.
- Excision: Excision involves the surgical removal of the affected tissue. This method may be effective for treating larger lesions but can cause scarring.
- Mohs micrographic surgery: Mohs micrographic surgery is a specialized surgical technique that involves the removal of tissue in stages and the examination of each stage under a microscope to ensure that all affected tissue has been removed. This method may be effective for treating larger lesions but can cause scarring.