Vulvar sarcoma is a malignant neoplasia originating from the precursors of mature cells forming soft tissues. Pathology is manifested by a rapidly increasing node in the thickness of the female external genitalia. The tumor is characterized by a hematogenous metastasis pathway with the development of secondary foci in the lungs and a tendency to local recurrence. Gynecological examination, introscopic methods (ultrasound, MRI), morphological analysis of the biopsy, karyotyping of tumor cells are used to diagnose neoplasia. The treatment is operative, can be supplemented with radio and polychemotherapy.
Vulvar sarcomas mostly originate from mesenchymal cells and belong to the subgroup of malignant soft tissue neoplasia. Among all malignant neoplasms of the external genitals, the proportion of sarcomas is 1-2%. The age of patients has a wide range – from infancy to old age, the peak of morbidity is observed in 20-50 years. In children under 10 years of age, rhabdomyosarcoma is more often observed, in adults – leiomyosarcoma. Other most studied types are epithelioid, alveolar sarcoma, liposarcoma, bulging dermatofibrosarcoma.
Currently, predisposing conditions and risk factors for tumor development have not been studied. It is noted that soft tissue sarcomas occur more often in individuals with genetic pathology: Lee-Fraumeni syndrome, Gardner syndrome, von Recklinghausen’s disease, Gorlin-Goltz syndrome, Bourneville-Pringle disease, Werner syndrome. Increases the risk of morbidity long-term contact with carcinogens: asbestos, arsenic, chlorvinyl. There is a hypothesis of the induction of sarcomas by herpesvirus of the eighth type, proven so far only in relation to Kaposi’s sarcoma.
Normally, mesenchymal cells mature, acquiring a specialization characteristic of a particular type of connective tissue. The development of sarcoma is based on an unknown mechanism that leads to the loss of the ability of progenitor cells to mature and further differentiate and activates their rapid reproduction, which leads to the growth of a malignant tumor.
The neoplasm is localized deep in the muscles or between them. Initially, the sarcoma located in the muscle is clearly delimited by the fascia, and the intermuscular neoplasia is a pseudocapsule formed by compacted adjacent tissues. As the tumor develops, these barriers germinate, destroying neighboring structures. Sarcomas are distinguished by multicentric growth – the simultaneous formation of several rudiments, which explains the frequency of relapses. Tumor cells are easily separated and spread throughout the body, forming secondary foci (metastases). Vulvar sarcoma are characterized by hematogenous metastasis with mainly lung damage. Lymphogenic metastasis is observed in 20% of cases of a common process, this way is characteristic of rhabdomyosarcoma and skin ulceration.
Accurate staging of vulvar sarcoma is necessary for the choice of treatment tactics. In American oncogynecology, the international classification of tumors according to the TNM system has been adopted, where the letter T denotes a tumor, N – regional lymph nodes, M – distant metastases. In addition, to determine the stage of soft tissue sarcoma, information about its differentiation is required ‒ this parameter is indicated by the letter G.
- Stage IA (G1-2T1a-bN0M0) is a superficial or deep tumor less than five centimeters in the largest dimension, highly or moderately differentiated. There are no signs of metastatic lesion of regional lymph nodes and distant organs.
- Stage IIA (G2T2a-bN0M0) is a deep or superficially located lesion with a size of five or more centimeters, differentiation is moderate. No metastases were detected.
- Stage IB (G3-4T1a-bN0M0) – the depth of the focus is any, its size is less than 5 cm, differentiation is low. No metastases were detected.
- Stage IIB (G3-4T2aN0M0) – superficial tumor ≥ 5cm, low degree of differentiation or undifferentiated. There are no metastases.
- Stage III (G3-4T2bN0M0) is a deeply located lesion ≥ 5cm, the degree of differentiation is low. There are no metastases.
- Stage IV (G–ANY1M0 or G-ANY1M1) is a tumor of any size and depth of location in the presence of metastases in regional lymph nodes and (or) in distant organs.
By superficial we mean foci located above the fascia, without its germination. Deep tumors are located under the fascia or germinate it.
Suspicion of sarcoma may arise when a node is found in the thickness of the pubis or, more often, the labia. This may be a seal under the skin or a bulging formation. Pathology can manifest itself by the appearance of several nodules, eventually merging into one dense tumor. The formation can be painless or cause pain during palpation, walking. Characteristic symptoms of malignant neoplasia are rapid growth of the node and loss of mobility (the formation is tightly soldered to adjacent tissues). Alarming signs can also include a change in the color of the skin above the tumor (the acquisition of a blue or purple hue), its ulceration, the manifestation of a vascular network, a local increase in the temperature of the affected area, edema.
The clinical picture of various types of vulvar sarcoma is diverse. Leiomyosarcoma is characterized by a subcutaneous location, node soreness, and a tendency to ulceration. Bulging dermatofibrosarcoma is a painful hard nodular formation protruding under thinned skin, bluish-red in color with areas of hemorrhages and ulceration. Rhabdomyosarcoma manifests itself as a rapidly growing, painless, cluster-like sedentary node, can be fixed to the skin, the skin often sprouts, while ulcerating and bleeding. Liposarcoma grows slowly, is painless, relatively mobile, well delimited and does not ulcerate.
Disseminated vulvar sarcomas are accompanied by metastatic foci in the lungs. Signs of the growth of secondary neoplasms: cough, shortness of breath, chest pain, fever attacks, loss of appetite, fatigue. In the later stages, severe respiratory insufficiency and weakness, cachexia are added. Lung damage is the most common cause of death in patients with vulvar sarcoma of the external genitals.
A neglected primary tumor can cause a lot of suffering. Over time, an aggressively growing neoplasm reaches the surface of the skin and protrudes outward in the form of a lumpy bleeding rosette. Later, the node undergoes necrotic decay with general intoxication, non-healing ulcers, abundant, foul-smelling purulent discharge, bleeding.
The tasks of diagnostic measures are the detection of the formation, its histological identification, assessment of the local status, finding out the extent of the tumor process. The tumor is detected by the finger method during a gynecological examination: sarcoma can be suspected by the high density of the node, its lack of mobility, and the indistinctness of the contours. Comprehensive diagnostics includes the following stages:
- Visualization of the primary focus. With small, well-delimited nodes, ultrasound of the vulva is performed, in the case of voluminous formations soldered to the surrounding structures, an MRI of the pelvis is prescribed. Signs such as increased density, heterogeneity of the structure, hypervascularization of the node, with a high probability indicate the presence of sarcoma. The study also determines the exact size of the tumor and the depth of germination of surrounding tissues.
- Laboratory verification. To obtain a sample of tumor tissue from small (less than 2-3 cm) foci, a multifocal biopsy is performed, in the case of more voluminous formations, an open biopsy is prescribed. Due to the morphological similarity of different histogenetic groups of sarcomas, histological examination of the biopsy is supplemented by immunohistochemical analysis. If it is not possible to determine the histogenesis of the tumor, a cytogenetic analysis is performed. This approach makes it possible to verify the diagnosis and obtain accurate information about the histological type of vulvar neoplasia, its proliferative activity and biological aggressiveness.
- Visualization of possible metastases. In order to assess the prevalence of the neoplastic process, ultrasound of the lymph nodes of the inguinal region, MRI of the abdominal cavity and retroperitoneal space, CT of the thoracic cavity are performed. According to the results of the studies, it is possible to judge the presence (absence) of regional and distant metastases.
Differential diagnosis of vulvar sarcoma is carried out with other vulvar pathologies: inflammatory processes (bartholinitis, abscess), cyst of the bartholinium gland, benign (fibroma, lipoma, lymphangioma, cavernous hemangioma) and malignant (adenocarcinoma of the bartholinium gland, squamous cell carcinoma, Paget’s cancer) tumors.
The tactics of treatment depends on the stage of the neoplastic process, the histological subtype and the degree of malignancy of the tumor, the age of the patient, the presence of concomitant diseases. The best long–term oncological results are provided by complex treatment with the involvement of a number of specialists – oncogynecologist, radiologist, chemotherapist, pathologist.
- Surgical intervention. This method is the main one in the treatment of sarcomas of the external genitals. With small superficial tumors with a low potential for malignancy, surgical operation allows to achieve a full therapeutic effect, in other cases it is one of the stages of treatment. Surgical intervention can be performed in the volume of a wide excision of the neoplasm, hemivulvectomy or vulvectomy.
- Radiation therapy. Most types of sarcoma are more or less sensitive to ionizing radiation. This method is used for volumetric formations and in the case of low differentiation of the tumor. Radiation treatment allows you to destroy the most active tumor cells, eliminate subclinical neoplasia foci, reduce the volume of neoplasm, distinguish it from healthy tissues, and stop peritumorous inflammation. Radiotherapy can be performed before, during and after surgery.
- Chemotherapy. It is performed in combination with surgical and radiological methods for subtypes sensitive to cytostatic drugs. Preoperative chemotherapy reduces the volume of the tumor, and postoperative reduces the risk of recurrence. Treatment is carried out by courses of polychemotherapy, combining platinum derivatives, anthracyclines, alkylating drugs.
Prognosis and prevention
Due to the diversity of cell types and the exceptional rarity of pathology, there are currently no reliable survival statistics for each histological type. On average, with verified radical removal of the tumor and the absence of relapses within a year, 20% of patients cross the five-year threshold of survival.
Preventive measures are aimed at early detection of primary sarcoma and its relapses after treatment. In order to detect the primary focus in a timely manner, all women need an annual (or, according to the situation, with appropriate symptoms) visit to a gynecologist. Relapse control is carried out by an oncogynecologist within the framework of lifelong dispensary monitoring of patients treated for vulvar sarcoma.