Dermatofibrosarcoma protuberans is a malignant tumor of connective tissue origin. It is prone to slow growth and invasion of surrounding tissues. Distant metastases are rare. Usually, a dermatofibrosarcoma protuberans is localized in the area of the trunk or upper shoulder girdle. At the initial stage, it is a dense reddish, purplish-bluish or brownish spot. Within a few years or decades, it turns into a nodular tumor-like formation protruding above the surface of the skin. The diagnosis is established on the basis of anamnesis, examination data and the results of additional studies. The treatment is operative.
Dermatofibrosarcoma protuberans (tuberous fibrosarcoma of the skin, Darrier-Ferrand dermatofibrosarcoma, recurrent dermatofibromioma) is a rare connective tissue tumor of moderate malignancy. It was first described as an independent disease in 1924. Dermatofibrosarcoma protuberans has been growing for several years or even decades, is not prone to metastasis, and is gradually embedded in the underlying tissues. Metastases, as a rule, are detected only after repeated relapses. It affects young and middle-aged people more often. In 10% of cases, it is diagnosed in children. Researchers’ opinions on the prevalence in men and women differ. Some experts believe that dermatofibrosarcoma protuberans equally often affects representatives of both sexes, others believe that women suffer 2-4 times less often than men. The treatment is carried out by specialists in the field of oncology and dermatology.
The causes and mechanisms of the development of this pathology have not yet been clarified. There are versions of vascular and fibroblastic origin. Some researchers point to a possible connection with trauma, others to the presence of chromosomal abnormalities. The size of the tumor depends on the duration of the disease and can range from a few millimeters to 10-15 centimeters. Usually, a dermatofibrosarcoma protuberans is diagnosed when its diameter reaches several centimeters.
The neoplasm is dense, fibrous, consists of bundles of spindle-shaped cells. The cells are monoform, elongated. The level of cell differentiation varies, a small number of atypical mitoses may be detected. The structure of collagen, as a rule, is not changed, sometimes signs of mucosal degeneration are found. Collagen fibers and bundles of fibroblasts of the dermatofibrosarcoma protuberans form a variety of structures resembling rings, bundles and swirls, which is why the tissue acquires a characteristic “moire” appearance.
The tumor forms many root-like small outgrowths that penetrate into the underlying tissues. In the initial stages, it is a plaque formed from several nodules. Subsequently, the number and size of nodes increase. The skin over the dermatofibrosarcoma protuberans is thinned, with a long duration of the disease, bleeding or crusted erosions and ulcers may appear on the surface of the neoplasm.
The tumor usually occurs at the age of 20-40 years, can be located on any part of the body, but is more often localized in the back, abdomen, chest or proximal parts of the upper extremities. Sometimes a dermatofibrosarcoma protuberans appears on the neck or scalp. The lower extremities and distal parts of the upper extremities are very rarely affected. In the early stages, it may resemble a lipoma or scar. As a rule, it is single. In some cases, several nodes are found that are prone to merging.
The surface of the dermatofibrosarcoma protuberans in the initial stages is smooth or slightly bumpy. The color is brownish, reddish, purple or with a bluish tinge. As a result of slow growth over several years or decades, the primary focus turns into a tumor-like node protruding above the surface of the skin. The skin over the dermatofibrosarcoma protuberans is atrophied, tense. Initially, the node is mobile, as the underlying tissues germinate and adhesions form, the mobility of the tumor decreases.
Usually dermatofibrosarcoma protuberans is painless, less often patients complain of minor or moderate pain in the area of the neoplasm. With a prolonged course of the disease, erosions covered with serous-hemorrhagic crusts can be detected on the surface of the tumor. Sometimes, usually after multiple relapses, the dermatofibrosarcoma protuberans metastasizes to regional lymph nodes and distant organs. It should be borne in mind that the tumor, even without metastasis, can deeply germinate the underlying tissues, affecting the fascia, bones, muscles and organs located under them.
The diagnosis is established on the basis of clinical manifestations and data from additional studies. Due to the small number of specific symptoms, the main diagnostic techniques are histological and microscopic examination of a tissue sample taken by open or aspiration biopsy. The presence of bundles of elongated cells, signs of proliferation of fusiform cells, a small number of atypical mitoses and a characteristic “moire” pattern indicate in favor of dermatofibrosarcoma protuberans.
There are no specific immunochemical markers of the tumor. Differential diagnosis of dermatofibrosarcoma protuberans is carried out with tumor forms of fungal mycosis, fibrosarcoma, dermatofibromioma and gum syphilis. When making a final diagnosis, they are based on microscopy and histological examination data. Ultrasound of internal organs, chest x-ray and other techniques are used to detect distant metastases.
Surgical treatment is carried out as planned on an outpatient basis or in a hospital setting. The Mohs operation is considered the most effective, during which a dermatologist excises a visible tumor, “capturing” 3-5 centimeters of unchanged tissue. After excision, the clinical laboratory assistant performs mapping – performs sections of the dermatofibrosarcoma protuberans with a thickness of 1 millimeter, stains the samples with special dyes and studies them under a microscope to determine the boundaries of the tumor.
Based on the data obtained during microscopic examination, the doctor determines in which direction the dermatofibrosarcoma protuberans spreads, and, if necessary, excises the next section of tissue. Then this area is also studied under a microscope, etc. This technique allows you to determine with high accuracy the true boundaries of the spread of the tumor and makes it possible to minimize the number of relapses. If a major defect occurs after the removal of the neoplasm, plastic surgery is performed.
In some cases, the dermatofibrosarcoma protuberans cannot be completely excised due to the peculiarities of its localization and the nature of the affected underlying tissues. For example, a neoplasm located near a joint or vertebra can germinate the joint capsule and bone structures. In such cases, radiation therapy is used, but reports on the effectiveness of this method for dermatofibrosarcoma protuberans vary. Some researchers point to a decrease in the tumor, others talk about the possibility of more aggressive growth. Chemotherapy is ineffective due to the slow growth of the neoplasm.
The prognosis for dermatofibrosarcoma protuberans depends on the duration of the disease and the number of relapses. According to various data, the probability of recurrence after radical surgery ranges from 10 to 60%, which may be due to differences in the severity and prevalence of the process, as well as the chosen surgical technique. Relapses may occur 10 years or more after excision of the dermatofibrosarcoma protuberans, therefore, long-term follow-up is indicated for all patients. During the first three years after surgery, patients are examined every 3-6 months, then the examination is carried out annually. In the presence of repeated relapses, more frequent examinations are required due to the increased risk of distant metastases.