acanthosis nigricans
Introduction
Introduction to black acanthosis Acanthosis nigricans (acanthosisnigricans) is a rare skin disease. In certain specific areas, there are pigmented brown-to-grey pigmented and papilloma-like keratotic skin lesions. There are many types and different prognosis. basic knowledge The proportion of illness: the incidence rate is about 0.0005%-0.0007% Susceptible people: no specific population Mode of infection: non-infectious Complications: pruritus
Cause
Cause of black acanthosis
Genetic factors (65%):
Benign acanthosis nigricans, as a kind of genetic syndrome, has irregular autosomal dominant inheritance, has nothing to do with visceral diseases, benign acanthosis nigricans and endocrine diseases: except for hereditary forms, benign acanthosis nigricans can be associated with pituitary, adrenal and Ovarian tumors occur, often in adolescence, and obesity does not necessarily exist.
Disease factors (35%):
Malignant acanthosis nigricans: This disease is almost always related to visceral tumors. About 60% of patients have skin symptoms and visceral malignant progress. About 20% of patients have skin symptoms before malignant tumors for several years. About 20% of patients with malignant tumors are primary. Skin disease is secondary.
Pathogenesis
The pathogenesis is still unclear, benign acanthosis nigricans, irregular autosomal dominant inheritance, no visceral disease, malignant acanthosis nigricans, about 60% of patients with skin symptoms and visceral malignant progress, about 20% of patients with skin symptoms A few years before malignant tumors, about 20% of patients with malignant tumors are primary, and skin diseases are secondary.
Prevention
Black acanthosis prevention
Acanthosis nigricans can occur at any age and is less common. About 50% of the patients after the middle age have a cancer. Severe vaginal mucosa can occasionally be accompanied by non-pigmented papillary lesions or pigmented spots.
Complication
Black acanthosis complications Complications pruritus
In malignant acanthosis, about 60% of patients have skin symptoms that progress synchronously with the degree of visceral malignancy. About 20% of patients have skin symptoms that precede malignant tumors for several years.
Symptom
Symptoms of black acanthosis common symptoms skin affected by the skin black itching skin pigment deepening glucocorticoid secretion excessive itching pore hyperkeratosis hyperplasia
The appearance of various types of acanthosis nigricans is consistent, the severity of which is different, symmetry, the area affected by the skin is the armpit, the flexion of the neck and the napkin area, the vulva, the inner thigh, the face, the elbow fossa, the armpit, Navel, back of the hand, areola, foot, eyelids and nasal vestibule.
The main symptoms are warts, papillary hyperplasia, hyperkeratosis and pigmentation. The initial changes are stained yellow, gray or brownish yellow, followed by melanin deepening, and the boundary between the skin and the surrounding skin is not clear, skin wrinkles and wrinkles A velvety papillary-like sacral lesion occurs, and the ash-to-black hyperplasia often leads to a cockroach-like skin sputum, which has varying degrees of hyperkeratosis. Eventually, sputum sputum can occur, and the affected area can be limited or extensive, such as the whole Axillary fossa, the most serious papilloma-like hyperkeratosis in the center of the lesion, tends to reduce the edge lesions, surrounded by melanin deepening zone, impregnation occurs in the interphalangeal region, which in turn stimulates proliferation, in the malignant type, palm is particularly susceptible to fatigue and the entire skin is clearly dry and rough.
Oral mucosal changes are mainly characterized by velvety coat damage on the tongue, but papillary neoplasms can also occur, and can also occur in the lips and tendons.
When skin lesions are impregnated, patients with acanthosis nigricans may develop some subjective symptoms and itching. Itching is more common in malignant acanthosis, sometimes very serious.
Examine
Examination of black acanthosis
Histopathology: The pathological changes of various types of acanthosis nigricans are the same, the epidermis is moderately hyperkeratotic and papillary-like hyperplasia, and the basal cell layer hyperpigment is a typical feature. The tissue image appears flattened seborrheic keratosis and epidermis .
Diagnosis
Diagnosis and diagnosis of acanthosis
According to the increase of pigmentation in the skin folds, with sputum proliferation, histopathology shows papillary-like hyperplasia, should consider the diagnosis of the disease, it is important to distinguish between benign and malignant, malignant black spine skin disease usually occurs in adulthood, severe damage, limbs and mucous membranes Often involved, pigmentation is significant, skin lesions are severe, and itching.
It should be differentiated from proliferative pemphigus, proliferative pemphigoid, and Darier disease.
