Acanthosis nigricans of the vulva

Introduction to vulvar black acanthosis Vulvar black acanthosis is a rare vulvar skin disease characterized by vulvar pigmentation, papillary hyperplasia, hyperkeratosis, and symmetric distribution. basic knowledge The proportion of illness: 0.0025% Susceptible people: women Mode of infection: non-infectious Complications: pigmentation spots

The cause of vulvar black acanthosis

(1) Causes of the disease

The cause of vulvar acanthosis is unclear. It may be caused by a cell-level enhanced stimulating factor acting on receptors for keratinocytes and fibroblasts. The tumor product seems to be the cause of malignant acanthosis, but insulin resistance is It is considered to be the cause of most patients with acanthosis nigricans without malignant tumors. The binding of insulin to its classical receptor produces a biological effect. The receptor is a single-encoding glycoprotein located on the short arm of chromosome 19 in the cell membrane. The upper insulin forms a complex with its receptor to dissolve the cytoplasm, and the receptor can be reused or degraded in the lysosome. In this complicated process, the insulin receptor function can be blocked by various defects, resulting in insulin resistance. These defects include lack of insulin or insulin antibodies, decreased levels of classical insulin receptors or decreased binding, and abnormal signaling due to failure to activate tyrosine kinase receptors. Insulin resistance can also occur in insulin-like receptors. High concentrations of insulin stimulate insulin-like growth factor 1 receptors and mediate epidermal cell proliferation For example, high-concentration insulin can also bind to growth-like peptide receptors to stimulate growth and form type A syndrome. Some patients with acanthosis nigricans have insulin receptor antibodies, indicating that acanthosis nigricans is associated with various autoimmune phenomena and characteristics. It can also explain the symptoms of various type B syndromes. Most of the acanthosis nigricans are caused by the secretion of tumor products. This secretion has insulin-like activity at the level of cellular receptors, such as transforming growth factor (TGF). -a) Structurally related to epidermal growth factor (EGF), but antigenicity is a factor that may occur in acanthosis nigricans because it has a significant mitogenic effect on keratinocytes in vitro.

Acanthosis nigricans may also be caused by drugs or autoimmunity. For example, subcutaneous injection of insulin can cause local acanthosis nigricans, and one case of acanthosis nigricans occurs in graft-versus-host response.

(two) pathogenesis

High concentrations of insulin can stimulate DNA synthesis and cell proliferation through insulin-like growth factor alpha-1 (IGF-1), IGF-1 receptor in skin keratinocytes, ovary and heart, and tumor secretory products in patients with malignant acanthosis nigricans. Insulin-like activity, wherein, for example, transforming growth factor a' (IGF-) is structurally related to epidermal growth factor (EGF), the former can promote the mitosis of keratinocytes through the amplification of EGF receptor, causing its proliferation to occur. The disease, in addition, can also be caused by other factors acting on the level of cellular receptors such as drugs (nicotinic acid, diethylstilbestrol, insulin) or autoimmunity. If it is reported that subcutaneous injection of insulin can cause local acanthosis nigricans, kidney transplantation Acanthosis nigricans occurs after immunosuppressive therapy in patients.

Histopathology: mild epidermis, moderate hyperkeratosis and hyperplasia of papilloma-like tumors, irregular thickening of the spinous layer, dermal papilla protruding upwards, light depression in the nipple, moderate acanthosis hypertrophy, and full of horny, The scalp on the top and the periphery of the nipple is thinned, the basal layer has mild pigmentation, the melanocytes are visible in the dermis, and the lymphocytes infiltrate around the blood vessels.

Vulvar black acanthosis prevention

Regulate the diet structure, properly reduce weight; actively treat medical diseases; drugs should be removed from the disease; good follow-up.

Vulvar black acanthosis complications Complications

Severe vaginal mucosa can occasionally be accompanied by non-pigmented papillary lesions or pigmented spots.

Vulvar black acanthosis symptoms common symptoms pruritus pigmentation reticular pigmentation ecchymosis pore hyperplasia leukopenia white nail skin dry

Vulvovaginal acanthosis is often a part of acanthosis nigricans in the whole body or parts of the body, mainly in the groin, upper thighs, haze, pigmented spots and velvety thickening at the labia majora, which may be associated with multiple skin blemishes, generally without discomfort. Patients with malignant acanthosis can have itching, and progression and prognosis vary by type.

The disease can be divided into 8 types, but the basic skin damage is similar, only the severity, the distribution range, the presence or absence of comorbidities and malignant tumors are different, the skin first appears pigmentation, dry and rough, then the skin lesions gradually thicken, skin The pattern is deepened, and the surface is densely packed with small papillary growth or velvet-like, and the pigmentation is gradually deepened, which is taupe or brownish black or black. In severe cases, the skin is thick and has papillary or sacral nodules on the surface. Skin lesions occur in the neck, head, armpit, nipple and areola, umbilicus and elbow, kyphosis of the knee flexor, scalp thickening with papilloma and hair loss, tarsal and bulbar conjunctival tarnish , or papillary hyperplasia, because the nipple hyperplasia can block the lacrimal duct and cause tears, eyelid hypertrophy can also block the meibomian gland pores, oral mucosa and tongue can also be thickened and papillary-like hyperplasia, but generally no pigmentation, nails It becomes brittle and can be thickened, white nails, etc.

Benign acanthosis nigricans

For rare hereditary skin diseases, autosomal dominant inheritance, often have a family genetic predisposition, have different phenotypic penetrance rates, occur after birth or early childhood, early manifestations of unilateral skin lesions, epidermal hernia, sometimes combined with multiple Sexual melanocytes sputum, skin lesions stopped developing in puberty, and remained stable or slowly decreased. In the family survey of 13 patients, there were 1 or more of the same family in 9 people. Obesity has nothing to do with the disease, Chuang et al. 1995) reported a familial acanthosis nigricans, the mother is a 35-year-old acanthosis nigricans, 7-year-old son and 5-year-old daughter are suffering from acanthosis nigricans, 3 have no eyebrows and eyelashes, mother's armpits are hairless, shame is scarce, The boy has congenital heart disease and left eye cataract, so this family member acanthosis nigricans with ectodermal defects.

2. Special hair style is not associated with malignant tumors, congenital or endocrine diseases, but often accompanied by obesity, obesity has insulin resistance, formerly known as pseudo-black acanthosis, Hud (1992) reported, random selection in adult obesity clinic 34 adults with obesity were examined. 74% (25/34) of the blacks had different degrees of acanthosis nigricans, and 33% of patients with ideal body weights of 120% to 150% had acanthosis nigricans; more than 120% of ideal body weight Of the 200% of patients, 82% were associated with acanthosis nigricans, and 4 of the patients with an ideal body weight of 250% were associated with acanthosis nigricans, while only 57% (8/14 of the obese whites) had acanthosis nigricans. The average blood insulin concentration after fasting in obese patients with acanthosis nigricans was higher than that in patients without acanthosis nigricans. When the patient's weight returned to normal, acanthosis nigricans could resolve.

3. Endocrine type

Often accompanied by endocrine diseases, especially common in the secretion of pituitary gland and adrenal lesions, such as acromegaly, Addison disease, diabetes, etc., such as Brockow et al (1995) reported a 12-year-old girl, due to increased serum insulin Acanthosis nigricans develops.

(1) Insulin-resistant type A syndrome: Type A syndrome is more common in young women, with masculine symptoms or excessive growth rate, also known as HAIR-Acanthosis nigricans syndrome, ie hyperandrogenism (HA), insulin resistance ( 1R) and acanthosis nigricans, familial, often infancy, some hairy and polycystic ovary, acromegaly, clitoris hypertrophy and muscle spasm, acanthosis nigricans lesions are often diffuse, adult lesions Rapid development, high testosterone levels in the blood.

(2) The onset of insulin-resistant type B syndrome is late, the average age of onset is 39 years old, the symptoms of acanthosis nigricans are different, and may be combined with lupus erythematosus, scleroderma, Sjogren's syndrome, vitiligo and Hashimoto's thyroiditis, but generally There is only laboratory evidence of autoimmunity, such as high titers of anti-DNA antibodies and leukopenia.

4. Malignant type

It is induced by malignant tumors, which is different from the common acanthosis nigricans. The latter has an early onset age and often does not expand. The malignant acanthosis nigricans has three kinds of skin markers of other visceral malignant tumors, namely the Lesser-Trelat sign. Natural red skin papilloma and palmar keratosis, acanthosis nigricans and these three skin markers are considered to be the same response to a genetic or malignant related factor, these three signs often appear before acanthosis nigricans It also rarely coexists with other skin lesions of visceral tumors, such as thick-skinned periostosis, paraneoplastic pemphigus and enlarged fetus, lesions develop rapidly, severe and extensive, pigmentation is obvious and not limited to increase Thick skin lesions, mucosal and mucous membrane junctions also have typical skin lesions. There are papillary hyperplasia around the eyes and lips. The nails become brittle and have longitudinal sputum. The skin lesions often have itching or irritation.

According to a recent statistic, acanthosis nigricans first occurs in tumors at 5l/74, accounting for 69% (Gross). Curth believes that tumor latency is 10 to 15 years. Acanthosis nigricans can combine more than one tumor. Related to acanthosis nigricans, it is necessary to conduct a clinical investigation to understand the relationship between acanthosis nigricans and tumors in the pathogenesis, and to determine whether the skin lesions have subsided after the tumor is removed. Curth pointed out in a retrospective analysis that 177 cases of malignant black spine 92% of the patients were abdominal tumors, 69% of which were gastric cancer, others were lung cancer, liver cancer, cervical cancer, breast cancer and ovarian cancer, and most of the internal tumors were adenocarcinoma.

5. Acromegaly

It is more common in black people. It has also been found in China. The author has seen one case. The skin lesions are limited to the symmetry of the back of the hand and the foot. It is velvety-like hyperkeratosis, brown, a variant of acanthosis nigricans, good overall health, no Other comorbidities.

6. Unilateral acanthosis

This type may be the earliest manifestation of bilateral benign acanthosis nigricans, but it can also be unilaterally distributed, which may be sputum-like lesions. It is also known as sputum-like acanthosis nigricans, which is irregular autosomal dominant inheritance. Occurs at birth, during childhood or adolescence, the lesions gradually expand over a certain period of time and then remain stable or subside.

7. Drug-induced acanthosis

This type is rare, and may cause pathogenic drugs such as corticosteroids, niacin, diethylstilbestrol, insulin, pituitary extract, triazine benzamide, methyltestosterone, oral contraceptives and fusidic acid (fusidic acid). Local topical fusidic acid (fusidic acid) can cause skin lesions of acanthosis nigricans.

8. Mixed acanthosis nigricans

There are two kinds of lesions of acanthosis nigricans at the same time. It is common to have malignant acanthosis nigricans in patients with other types of acanthosis nigricans. For example, Curth reported that one child had unilateral acanthosis nigricans, and then the lesions were converted into bilateral And abdominal malignant tumors appear.

In addition, Hirschowitz syndrome, a syndrome proposed by Hirschlowitz in 1989, has a wide range of acanthosis nigricans, combined with childhood familial complete neurological deafness, progressive peripheral sensory nerve demyelination, and gastrointestinal Dao disease, lipodystrophy and acanthosis nigricans were first described by LawVence in 1946. Slip reported the same patient in 1959, so it is also called Lawvence-Seip syndrome. This sign is hereditary and acquired. Acanthosis nigricans can be combined with pan. Complete subcutaneous fat disappears and has severe insulin resistance.

Other syndromes associated with acanthosis nigricans include dwarf goblin syndrome, hepatolenticular degeneration, Bloom syndrome, Rud syndrome, pituitary basophilia, other pituitary tumors, family pineal hyperplasia, adrenal hyperplasia and Diabetes (RM syndrome), as well as some diseases in which autoantibodies include insulin receptor antibodies (such as lupus hepatitis, cirrhosis, lupus erythematosus, dermatomyositis, and scleroderma).

Examination of vulvar black acanthosis

Vulvar black acanthosis is a rare vulvar skin disease characterized by vulvar pigmentation, papillary hyperplasia, hyperkeratosis, and symmetric distribution. According to the disease, the skin has characteristic velvet-like thickening, pigmentation and special distribution, which is easy to diagnose. Histopathological examination can confirm the diagnosis.

Laboratory tests: blood biochemical tests, islet cell function tests, sex hormone levels.

Other auxiliary examinations: histopathological examination.

Diagnosis and diagnosis of vulvar black acanthosis

diagnosis

According to the disease, the skin has characteristic velvety-like thickening, pigmentation and special distribution, which is easy to diagnose, and histopathological examination can confirm the diagnosis.

Differential diagnosis

Female acanthosis nigricans need to be differentiated from vaginal hair follicle keratosis. The follicular keratosis is basically damaged by follicular papules. It is fused into proliferative flaky lesions under the armpits, groin and other wrinkles, with exudation and malodor. Pathological examination showed: poor keratinization, round body, grain cells, and fissures on the basal layer, which can be distinguished from acanthosis nigricans.

It is important to separate malignant acanthosis nigricans from other types of acanthosis nigricans, and to find visceral malignant tumors according to the characteristics of malignant acanthosis lesions for early treatment.

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