Primary esophageal malignant melanoma

Introduction to primary esophageal malignant melanoma Primary malignant melanoma (esophagus) is a malignant tumor of melanocytes present in the esophagus. It is extremely rare in clinical practice, accounting for 0.1% to 0.3% of esophageal malignancies. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: difficulty swallowing

Primary esophageal malignant melanoma etiology

(1) Causes of the disease

In recent years, it is generally believed that the origin of esophageal primary malignant melanoma is the melanocyte in the basal layer of the esophageal mucosa. The histological appearance is similar to that of cutaneous malignant melanoma. The prognosis of patients is very poor. The patient can survive for a long time after surgery or radiation therapy. For example, a 40-year-old female patient reported by Hamdy et al. (1991) has a preoperative symptom of 2 years of retrosternal pain with progressive dysphagia and weight loss. Preoperative esophageal barium meal angiography Examination showed a large irregular irregular soft tissue mass in the lower part of the esophagus; endoscopic examination revealed a black polypoid mass in the lower part of the esophagus, about 9cm × 6cm in size, protruding lumen, endoscopic biopsy diagnosed as esophagus Melanoma, the patient underwent major esophagectomy and esophago-gastric anastomosis. The postoperative pathological diagnosis was the same as the preoperative diagnosis. The patient survived for more than 12 years.

Allen and Spitz proposed in 1953 that the main criterion for diagnosing malignant melanoma originating in the esophagus is the junctional changes of the esophageal mucosa near the tumor. The histological manifestations of typical melanoma are found in tumor cells. melanin.

Pava et al (1963) reported that during the autopsy of 100 normal esophagus, 4 cases of esophageal mucosal epithelium were found to have typical melanocytes, melanin particles and neuronal dendrites (2 cases of melanocytes in the upper esophagus). Two other melanocytes are located in the middle esophagus. They speculate that the melanocytes in the esophageal mucosa are derived from the neural crest (the cell band on the dorsal side of the embryonic neural tube), that is, the epidermal melanocytes formed by the neural crest migrate to the esophageal epithelium. As a result, Tatteshi et al. (1974) and Ohashi et al. (1990) reported the presence of argyrophils and melanocytes in the normal esophageal mucosa of Japan, with an incidence of 8%, and can cause melanosis in the esophagus.

In 1970, Piccon et al reported the first case of esophageal primary malignant melanoma with total esophageal melanosis, but most esophageal melanoma patients did not have esophageal melanosis, considering that this tumor may originate from other more common Ways:

1 normal melanocytes derived from the esophageal mucosa;

2 metaplasia originating from normal esophageal epithelial cells;

3 or ectopic melanocytes originating in the esophageal epithelium during embryonic development. It is now believed that the melanocytes of the esophageal mucosa are directly derived from the neural crest of the human embryo, and the primary malignant melanoma of the esophagus originates from the basement membrane of the esophagus. (layer) of melanocytes.

(two) pathogenesis

Pathological morphology

The gross pathological morphology of the primary malignant melanoma of the esophagus is a surface-thick polypoid mass located in the esophageal lumen. The size of the tumor is very large. The maximum diameter varies from 2cm to 17cm, and the base or pedicle of the tumor is more Some tumors have nodular or lobulated appearance, and ulcers often form on the surface of the tumor, but some tumors cover the intact squamous cell mucosa; some tumors are black, brown, gray or dark brown. (Fig. 1), the tumors are mostly single-shot, and some cases have multiple polypoid lesions. This multiple lesion needs to be differentiated from its "satellite" nodules. About 12% of the cases have "satellite" nodules, some are tight. By the original tumor, and some away from the original tumor.

In some cases, there is no melanin in the gross specimens of the tumor. However, melanin is seen in the tumor cells during histological examination. Typical patients with pigmented esophageal melanoma, the esophageal mucosa adjacent to the tumor manifests as melanosis or melaninosis. The changes can be focal or diffuse, according to Di Constanzo and Umacher (1987), which can be seen in nearly 25% of patients with esophageal melanoma.

According to the diagnostic criteria and more stringent definition of melanoma, histological examination revealed that melanoma-free tumors in tumor cells should be classified as melanotic melanoma when classified, but most cases are not reported. Adhering to the above diagnostic criteria and definitions, the incidence of true melanoma-free melanoma is less than 2%.

2. Microscopic performance

The histological features of the primary malignant melanoma of the esophagus are the same as those of the malignant melanoma in other parts of the body. The esophageal squamous epithelium on the surface of the tumor is normal; the structure of the tumor tissue is diverse, and the tumor cells can be Arranged into nests, strips or adenoids; tumor cells are more consistent in size and shape, larger in cells, polygonal or fusiform; larger nuclei, often with thick eosinophils, mitotic figures More common; melanin particles can be seen in the cytoplasm; some pseudonuclear inclusions and abundant eosinophilic cytoplasm can be seen in some tumor cells (Fig. 2). Some authors divide the tumor cells into 5 types, ie, large epithelium. Cells, small epithelial cells, spindle cells, giant cells and balloon cells, of which large epithelial cells are most common.

According to some authors, borderline changes can be seen in the esophageal mucosa adjacent to the tumor, that is, there is melanocyte hyperplasia in the mucosal area and is connected with the tumor, and seeing this feature is the main sign indicating the boundary change, but the growth rate is very fast. The tumor can destroy or cover the borderline changes adjacent to the mucosal epithelium.

Under the microscope, it can be seen that tumors tend to grow into the esophageal mucosa and submucosa, which are characterized by radial staining. Some tumors infiltrate deep into the esophageal muscle layer, but cases with infiltration more than the esophageal wall are rare. Surgical removal of the tumor.

Esophageal malignant melanoma often grows vertically along the esophageal mucosa, easily invading local lymphatic vessels, lymph nodes and blood vessels, and local lymphatic metastasis and systemic hematogenous metastasis.

Di Constanzo and Umacher (1987) and other authors have performed electron microscopy on the disease and found that there are melanin precursors and melanin particles in the tumor cells.

3. Histological characteristics

In recent years, the histological features of esophageal primary melanoma are generally considered to include the following three aspects:

(1) Tumor cells contain melanin granules which have been confirmed by special staining.

(2) The tumor is derived from the malignant transformation of the esophageal squamous epithelial junction (junetional nevus), and the junctional sputum cells form a nest-like shape, which is prone to malignant transformation and form malignant melanoma.

(3) Microscopically, the esophageal mucosa and submucosal cells grow radially, and the tumor cells are mainly formed by three kinds of cells:

1 large epithelial cells: the cells are polygonal, the boundary is clear, and the melanin is small and uniform;

2 small epithelial cells: small cells, less melanin particles;

3 spindle cells: different melanin particles.

4. Good hair

Esophageal melanoma is mostly located in the middle and lower esophagus. According to Chalkiadakis and other review literatures, 7% are located in the upper esophagus, 7% in the upper esophagus, 24% in the middle esophagus, 22% in the lower esophagus, and 40% in the esophagus. In the lower segment, it can be seen that more than 80% of esophageal melanomas occur in the lower and middle esophagus, which is consistent with the predilection of the disease reported in the domestic literature.

5. Transfer route

Esophageal primary malignant melanoma is a rapidly fatal disease because tumor cells are easily metastasized through both lymphatic and hematogenous routes.

(1) lymphatic metastasis: local and distant lymph node metastasis is more common, especially intrathoracic lymph nodes, abdominal lymph nodes and supraclavicular lymph node metastasis are more common;

(2) Hematogenous metastasis: The main sites of esophageal primary malignant melanoma undergoing distant metastasis (distribution) are liver, lung, pleura, peritoneum, brain and bone, and some can be transferred to the left atrium.

According to clinical statistics from Eng et al in 1989, 30% to 40% of patients with primary malignant melanoma of the esophagus have lymph node metastasis or distant dissemination, regardless of the treatment, 85 % of cases died due to distant metastasis of the tumor, and the average survival time of the patient was 13.4 months.

6. Pathological diagnostic criteria

In the pathological diagnosis of human melanoma, the boundary change of the tumor surface or the epithelial tissue adjacent to the tumor was once regarded as evidence for the diagnosis of primary malignant melanoma of the skin. In 1953, Allen and Spitz expanded the concept of borderline change. As the primary criterion for diagnosing melanoma (including visceral melanoma), the most ideal criteria for diagnosing 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 be a borderline change region originating from the 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 borderline change.

(4) After careful examination, primary malignant melanoma of the skin, eyeballs and other parts of the mucosa can be excluded.

Some authors have found that esophageal primary malignant melanoma, which grows fast, can form ulcers and invade adjacent epithelial tissues in a short period of time, so sometimes it is not easy to determine the direct origin of borderline epithelial tissue. In addition, Eng et al ( 1989) Note that case reports of esophageal metastatic malignant melanoma are extremely rare and difficult to understand because melanoma in the stomach and small intestine are almost secondary to pigmentation, and patients with esophageal metastatic melanoma are within 1 year after onset. death.

Primary esophageal malignant melanoma prevention

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Primary esophageal malignant melanoma complications Complications, difficulty swallowing

The disease has no complications.

Primary esophageal malignant melanoma symptoms Common symptoms Dysphagia, swallowing pain, esophageal obstruction, weight loss, lymphadenopathy, black stool

The main clinical symptoms are swallowing pain and dysphagia. These symptoms are mostly caused by large tumors, occlusion of the esophageal cavity and ulceration on the surface of the tumor. It resembles esophageal squamous cell carcinoma and other esophageal malignant lesions that cause esophageal obstruction. Some patients There are post-sternal pain, discomfort or weight loss, and some patients have hematemesis and melena. These symptoms are not specific. According to some authors in China, more than 70% of the cases have a course of about half a year, according to Sabanathan et al. According to statistics, 7% of patients with primary malignant melanoma of the esophagus have left supraclavicular lymphadenopathy (metastatic lymph nodes), which should be noted when examining the body and cannot be ignored.

Examination of primary esophageal malignant melanoma

1. Histopathological examination

Microscopic examination of melanoma is mostly covered by esophageal squamous epithelium. The growth mode is firstly submucosal growth, not invading the muscle layer. Tumor cells can be nested, strip-like or acinar-like, and the cells are polygonal or shuttle. Shape, large nuclear, often with large eosinophilic nucleoli, there may be melanin particles in the cytoplasm, electron microscopic observation of the cytoplasm has a number of structures, such as anterior melanosome, mitochondria, endoplasmic reticulum, free ribosome, visible bridge.

2. Immunohistochemistry

Poor differentiation or non-pigmented malignant melanoma is difficult to distinguish from other small cell tumors. Therefore, immunohistochemistry is required. S-100 protein is widely distributed in malignant melanoma tissue and labeled with S-100 protein antibody. The positive rate of malignant melanoma cells can be as high as 90%, but its antigen specificity is poor, so it must be confirmed by the positive expression of HMB-45 antibody. Although the positive rate of HMB-45 is only 50% to 60%, its crossover The reaction is small, the positive cells are well located, and the diagnosis value and differential diagnosis value are relatively large.

For patients suspected of having esophageal malignancies (including melanoma), in addition to routine physical examination, the following tests should be performed.

Film degree exam

1. Chest X-ray film examination

These two tests have clinical significance in the display of metastases in the lung parenchyma and intrathoracic lymph nodes or metastatic lymph nodes. Esophageal malignant melanoma is prone to lung and pleural metastasis, and should be paid attention to in clinical work to avoid missed diagnosis. .

2. Esophageal barium meal examination

Esophageal primary melanoma in the X-ray esophageal barium meal examination, often manifested as esophageal cavity massive and polypoid filling defects, surface mucosa is rough, often ulceration shadow formation; tumor shadow edge comparison Clear and sharp, the metastatic melanoma of the esophagus affects the muscular layer of the local esophageal wall and has a smooth outer shadow (Figure 3). These X-ray signs are also non-specific and difficult to treat with esophageal squamous cell carcinoma. Identification of carcinosarcoma and leiomyomas, the main significance of this examination is to be able to determine the shape, size, location, extent and extent of esophageal involvement of the tumor, which is conducive to the clinician to determine the treatment plan.

3. Endoscopy

Endoscopic esophageal melanoma is a polypoid or lobulated mass with a wide base. The mass is located in the middle or lower part of the esophagus. It is usually single and sometimes has satellite lesions. Most tumors have ulcers and are brittle. It is easy to bleed. As mentioned above, the surface of the tumor can be black, brown, gray or dark brown under endoscopy. It is caused by different degrees of pigmentation. It is extremely rare for tumors to have large bleeding due to biopsy. Murray and Vasilakis believe that Esophageal melanoma can be clearly diagnosed by endoscopic biopsy. Joob et al (1995) suggest immunization of all polypoid tumors in the esophageal lumen that cause esophageal obstruction with a specific monoclonal antigen: HMB-45. Histochemical examination, positive for HMB-45 antibody, supports the diagnosis of malignant melanoma. The diagnostic accuracy of endoscopic biopsy is 55%.

According to the results of endoscopic biopsy of esophageal primary malignant melanoma reported by domestic authors, the rate of misdiagnosis is high, and the reason remains to be explored. Endoscopic cytology smears are not helpful for diagnosis.

4. Abdominal ultrasound examination and upper abdominal CT scan

Esophageal melanoma can be metastasized or disseminated to the abdominal lymph nodes, liver and peritoneum through lymphatics and blood, and hematogenous metastasis of the liver is the most common. Through abdominal ultrasound and CT scan, metastatic tumors and metastatic lymph nodes of intra-abdominal organs may be found. .

Diagnosis and diagnosis of primary esophageal malignant melanoma

The final diagnosis of primary malignant melanoma of the esophagus depends on the pathological examination of the surgically resected esophageal specimen. According to Sabanathan et al. (1989), 54% of primary malignant melanoma of the esophagus can be diagnosed by standard pathological examination, 1/3 ~1/2 of the cases had a borderline change in the esophageal mucosa adjacent to the tumor during histological examination. Currently, standard pathological examination combined with immunohistochemical examination, the diagnosis of esophageal melanoma is generally not difficult, but attention should be paid to the exclusion of metastasis. Sexual lesions.

Generally not confused with other diseases.

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