Complex pigment nevus is a benign brown pigment formation located simultaneously in the epidermal layer of the skin and the dermis. A complex nevus has the appearance of a rounded papule or wart with a diameter of up to 1 cm, rising above the skin level. His diagnosis includes examination, dermatoscopy and sciascopy, if necessary — ultrasound. Histology of a complex pigmented nevus is carried out after its removal. Given the likelihood of nevus transformation into melanoma, patients need to be monitored by a dermatologist. The safest and optimal ways to remove a complex pigment nevus are the radio wave method and surgical excision.
Together with the intradermal and borderline pigment nevus, the complex pigment nevus belongs to the main types of melanocytic nevi of epidermal origin. It begins its growth in the upper layer of the skin — the epidermis, and then sprouts into the dermis. Thus, unlike most other moles, a complex pigment nevus is located both in the epidermis and in the dermis. This fact was the reason for its name — dermoepidermal or complex nevus.
Complex pigmented nevus is a benign neoplasm of the skin. However, according to various authors, transformation into melanoma can occur in 50-80% of cases of complex pigmented nevus. Therefore, in clinical dermatology, it is classified as melanoma-threatening and requires a certain amount of oncological caution.
Due to its location in both layers of the skin, a complex pigmented nevus combines signs of intraepidermal (borderline) and intradermal nevus. The epidermal component of the nevus causes its intense brown, and in some cases almost black, color. The presence of an intradermal component contributes to the fact that the nevus is slightly raised above the general level of the skin and therefore may resemble an ordinary wart.
A complex pigmented nevus has the appearance of a papule or node of a domed, round shape. Its surface is often smooth, and the growth of bristly hair is noted on it. There are complex nevi with a keratinized or warty surface. In most cases, the nevus is located on the face or scalp, but it can have any localization. A complex nevus rarely reaches a significant size, usually its diameter does not exceed 1 cm.
Complex pigmented nevus is diagnosed by a dermatologist on the basis of examination data, dermatoscopy and syascopy of pigmented formation. To determine the degree of germination of the nevus into the dermis, ultrasound of the skin formation can be used. Suspicion of malignant degeneration of the nevus or melanoma is an indication for an urgent consultation with a dermatooncologist.
Conducting a biopsy of a complex nevus is dangerous for its injury, which can lead to malignant degeneration into melanoma. For this reason, histological examination of nevus tissues is carried out most often after its complete removal. It reveals the characteristic location of the nests of nevus cells both in the epidermis and in the dermis.
Differential diagnosis of complex pigmented nevus is carried out primarily with melanoma and other types of pigmented nevi: blue nevus, borderline pigmented nevus, Setton’s nevus, Dubreuil’s melanosis, as well as with warts, papillomas, senile keratoma, dermatofibroma.
Complex pigmented nevus requires the supervision of a dermatologist. The absolute indication for its treatment (removal) is regular traumatization or the appearance of signs of malignancy. Nevus removal can be carried out for cosmetic reasons. The methods of removal of complex pigment nevus include: laser removal, radio wave method and surgical excision. Electrocoagulation and cryodestruction are not used because of the danger of traumatization of the formation and its incomplete removal, which can stimulate malignant growth.
Laser removal of moles is applicable in the case of a complex nevus, if it consists in using a laser as a scalpel and allows for subsequent histological examination of the removed formation. It is most advisable to use the radio wave method or surgical excision of a complex nevus, since they make it possible to completely remove nevus cells, which is of great importance in terms of preventing melanoma.