Pathological diagnostic criteria
In 1953, Allen and Spitz expanded the concept of junctional changes as the primary criterion for the diagnosis of melanoma (including visceral melanoma). The most desirable criteria for the diagnosis of primary esophageal melanoma are as follows.
(1) The tumor should have the characteristic histological manifestations of melanoma, and the tumor cells should contain melanin.
(2) The tumor should originate from the junctional change area of esophageal squamous epithelium.
(3) Cells containing melanin can be found in the esophageal epithelial tissue adjacent to the tumor, confirming that this change is a junctional change.
(4) Primary malignant melanoma of the skin, eye, and other parts of the mucosa can be excluded by careful examination.
Metastatic pathways
Primary malignant melanoma of the esophagus is a rapidly fatal disease because the tumor cells can easily metastasize through both lymphatic and hematologic routes.
(1) Lymphatic metastasis: local and distant lymph node metastasis is common, especially intra-thoracic lymph node, abdominal lymph node and supraclavicular lymph node metastasis are more common.
(2) Hematogenous metastasis: The main sites of distant metastasis (dissemination) of primary malignant melanoma in esophagus via bloodstream are liver, lung, pleura, peritoneum, brain, bone and left atrium in order.
Prevalent sites: Esophageal melanoma is mostly located in the middle and lower esophagus.
The main clinical symptoms are painful swallowing, dysphagia, retrosternal pain, discomfort or weight loss, and in some patients, vomiting of blood and black stool. 70% of patients with primary malignant melanoma of the esophagus have an enlarged left supraclavicular lymph node (metastatic lymph node), which should be noted during physical examination and should not be ignored.
Examination
1.Histopathological examination.
2.Immunohistochemical examination S-100 protein is widely distributed in malignant melanoma tissues, and the positive rate of labeling malignant melanoma cells with S-100 protein antibody can be as high as 90%, but its antigen specificity is poor, so there must be positive expression of HMB-45 antibody to confirm the diagnosis.
In addition to the routine physical examination, the following tests should be performed for patients suspected of having malignant tumor of esophagus (including melanoma).
These two examinations are of clinical diagnostic significance to show metastases in the lung parenchyma and enlarged lymph nodes or metastatic lymph nodes in the chest. Esophageal malignant melanoma is prone to lung and pleural metastases.
2.Barium esophagogram is also non-specific and difficult to distinguish from squamous esophageal cancer, carcinosarcoma and smooth muscle tumor. The main significance of this examination is to clarify the shape, size, location, degree and extent of esophageal involvement, which is helpful for clinicians to determine the treatment plan.
3.Endoscopic examination of esophageal melanoma shows polyp-like or lobulated masses with wide base, mostly located in the middle or lower part of esophagus, usually solitary, sometimes satellite lesions can be seen. The surface of the tumor may appear black, brown, gray or dark brown under endoscopy, which is caused by different degrees of pigmentation. Murray and Vasilakis concluded that the diagnosis of esophageal melanoma can be made definitively by endoscopic biopsy of the tumor. Endoscopic cytology smear is not helpful for diagnosis.
4. Abdominal ultrasonography and CT scan of the upper abdomen. Esophageal melanoma can metastasize or spread to abdominal lymph nodes, liver and peritoneum through lymphatic tract and bloodstream, and bloodstream metastases in the liver are the most common. With abdominal ultrasound and CT scan, it is possible to detect metastases and metastatic lymph nodes in the intra-abdominal organs.
Treatment
Because primary malignant melanoma of the esophagus is highly malignant and prone to lymphatic metastasis and hematogenous dissemination, surgical treatment is less effective than for esophageal cancer, and more than half of the operated cases die within 1 year due to distant metastasis.
At present, the choice of treatment for esophageal malignant melanoma depends on the patient’s general functional status and the presence of distant metastases.
1.Surgical treatment
If the diagnosis is clear, the symptoms of dysphagia or painful swallowing are severe, the patient’s general health condition is good, and there is no extensive metastasis or distant metastasis, surgical treatment should be chosen. Radical total esophagectomy or near-total esophagectomy and esophage-gastric neck anastomosis is preferred. The main reason for adopting this procedure is the tendency of esophageal malignant melanoma to spread along the longitudinal axis of the esophagus. It is believed that there is not enough information to support that radical lymph node dissection can improve the long-term survival of patients. Patients die because of extensive tumor metastasis via bloodstream, and it has been proposed that patients do not need to undergo adjuvant radiation therapy after surgery.
2.Radiation therapy
It is mainly applied to patients with poor general functional status, high risk of surgery, clear metastases and refusal of surgical treatment. Some patients with esophageal malignant melanoma can get palliative treatment effect after simple radiotherapy, but the overall effect of simple radiotherapy are not ideal. The efficacy of fast neutron therapy is better for cutaneous melanoma, but the efficacy for esophageal melanoma is unknown.
3.Other treatments
Systemic chemotherapy, biological therapy and hormone therapy can be used as comprehensive adjuvant therapy for esophageal melanoma, however, the effect of all these therapies is not obvious. Malignant melanoma is not sensitive to chemotherapy drugs and is not treated clinically as a routine treatment. With the development of molecular biology, gene therapy may be a promising means of treating malignant melanoma of the esophagus.
Prognosis
The prognosis of patients with primary malignant melanoma of the esophagus is poor, with most patients dying within 2-5 years after treatment. According to Chalkiadakis et al. (1985), the 5-year survival rate was only 4.2%, and Sabanathan et al. (1989) noted that only 1/3 of patients survived for more than 1 year regardless of surgical treatment, radiotherapy, or other treatments, and the remaining 2/3 died within 1 year due to extensive metastasis of the tumor. According to the statistics of Joob et al. (1995) and others, the average survival time of patients with esophageal melanoma after radical esophagectomy is 14 months, with some patients surviving for 2 to 3 years; the 5-year survival rate is 4% after surgical resection of the tumor; about 2, 2% of patients with surgical treatment can achieve long-term survival, with survival time greater than 5 or 12 years. joob et al. from the literature A total of 5 long-term survivors were collected from the literature.
The prognosis of patients with primary malignant melanoma of the esophagus is very closely related to local lymph node metastasis and hematogenous dissemination, but there are no TNM staging criteria to date. In 1997, the UICC developed the postoperative TNM staging criteria for cutaneous malignant melanoma Table 1, which helps to estimate the prognosis of patients after surgery.