Vulvar Merkel cell carcinoma

　　1. Etiology

　　Vulvar Merkel cell carcinoma originates from the Merkel cell sensory receptor cells in the basal layer of the epidermis.

　　2. Pathogenesis

　　The tumor is located in the epidermis and invades the dermis. The yellow or purple mass is smooth in surface, with a size of 1.5-9cm, and hard in texture. The cut surface is grayish white, with irregular boundaries, accompanied by focal hemorrhage and necrosis.

　　Microscopic examination shows uniform small round cells arranged in trabecular, nest-like, or sheet-like patterns, occasionally with acinar structures. Cell boundaries are unclear, cytoplasm is scarce, nuclei are large, round or oval, vacuolated, granular chromatin, and multiple nucleoli. There are many mitotic figures, and apoptosis can be seen. Occasionally, typical squamous epithelial or glandular differentiation is accompanied. Tumor cells invade the dermis in a strip-like or trabecular manner, and can involve subcutaneous fat tissue. The tumor stroma is rich in blood vessels with proliferative vascular endothelial cell clusters. Vulvar Merkel cell carcinoma often accompanies vulvar intraepithelial neoplasia VIN III. Electron microscopy shows that some tumor cells contain dense neuroendocrine granules with clear membranes in the cytoplasm, tightly arranged under the cell membrane, and surrounding the intermediate filaments around the nuclear periphery.

　　Immunohistochemical examination shows that both low molecular weight keratins (including CK20) and neurospecific enolase (NSE) are positive. In addition to cytoplasmic positivity, most low molecular weight keratins show perinuclear granular positive staining. Chromogranin A (CgA), synaptophysin, and neurofilament protein can also be positive. Su et al. (2002) found that about 95% of Merkel cell carcinomas are CD117 positive. S-100, HMB45, CD43, and leukocyte common antigen (LCA) are mostly negative. Recently, Su et al. proposed to determine the lymph node metastasis by detecting CK20 in sentinel lymph nodes.

　　In Merkel cell carcinoma, the loss of chromosome 1p36 and the heterozygous deletion of 3p21 are common. Goessling et al. (2002) believe that the occurrence of the tumor may be related to the loss of the p73 tumor suppressor gene on 1p36.33 or the RASSF1A gene on 3p21, but in one case of vulvar Merkel cell carcinoma, GilMoreno et al. did not detect the overexpression of K-ras, N-ras, N-myc genes and the mutation of p53 gene.

　　Immunohistochemical examination of vulvar Merkel cell carcinoma shows that low molecular weight keratin (including CK20) and neurospecific enolase (NSE) are all positive. In addition to cytoplasmic positivity, low molecular weight keratin mostly shows perinuclear granular positive staining. Chromogranin A (CgA), synaptophysin, and neurofilament protein can also be positive. Su et al. (2002) found that about 95% of Merkel cell carcinomas are CD117 positive, S-100, HMB45, CD43, and leukocyte common antigen (LCA) are mostly negative. Recently, Su et al. proposed to determine the lymph node metastasis by detecting CK20 in sentinel lymph nodes. More than half of the patients have inguinal lymph node metastasis. It often occurs with trichilemmoma.

　　Vulvar Merkel cell carcinoma grows slowly, generally manifests as vulvar activity, painless mass, increased in a short period of time, mostly nodular, can also be plaque-like, some with surface skin ulceration and contact bleeding, stop growing after increasing to a certain degree, the course of the disease varies from a few weeks to a few months, in addition to mainly seen in the labia majora, 4 cases occurred in the labia minora, also seen in the vestibule gland, around the clitoris, posterior labial ligament, more than half of the patients have inguinal lymph node metastasis.

　　This tumor has strong invasive power, the course of the disease develops rapidly, and 17% of the cases die of extensive metastasis. Among them, 6 patients had inguinal lymph node metastasis at the time of consultation. Recurrence is seen within 1 to 2 months after surgery, common local recurrence with regional lymph node metastasis, of which 8 cases had distant metastasis. One case survived without tumor for 13 months after extensive vulvar resection, while the rest died within 11 days to 2.5 years, of which 6 died within a year.

　　1. Immunohistochemical examination: Low molecular weight keratin (including CK20) and neurospecific enolase (NSE) are all positive, tumor marker examination, secretion examination.

　　2. Histopathological examination.

　　I. Dietetic recipe for vulvar Merkel cell carcinoma

　　1. 300 grams of meat, 1 fresh river fish (500 grams), and 1 white radish. Cut the lamb into large pieces and put it into boiling water, boil with sliced radish for 15 minutes, and discard the soup and radish. Put the lamb into the pot, add water (about 2/3 of the pot capacity), scallion, ginger, and wine, and cook until tender. If the soup is too little, add some boiling water. Fry the fish with soybean oil until cooked through and put it into the lamb pot to cook for 30 minutes. Add salt, coriander, green scallion, and chopped scallion to the soup, and it becomes a delicious and tasty lamb and fish soup. It is mainly used for the nourishment after the operation of vulvar Merkel cell carcinoma.

　　2. Quail eggs 20 pieces, half an onion, 80 grams of carrots, 80 grams of asparagus, 4 tomatoes, 1 green pepper. Boil the eggs and use the shells. Cut the vegetables into small pieces. Boil the carrots just until they are cooked. Put 200 milliliters of soup, 40 grams of sugar, 45 milliliters of vinegar, 15 milliliters of wine, 20 grams of tomato sauce, 5 milliliters of sesame oil, 10 grams of flour, and mix them into a sauce. Heat 30 milliliters of oil in a pot, stir-fry the eggs and vegetables, add the sauce, and cook for a while before serving. It is used to treat anemia caused by chronic bleeding from vulvar Merkel cell carcinoma.

　　Second, what foods are good for vulvar Merkel cell carcinoma

　　1. Supplement beta-carotene. Beta-carotene can be converted into vitamin A in the body, which helps protect the immune system from attacks by free radicals and has a significant immune-enhancing effect. Studies have shown that a low intake of beta-carotene is a risk factor for vulvar cancer and cervical cancer.

　　2. Increase the intake of vitamin C. Vitamin C can inhibit viruses, enhance human immunity, including the production of antibodies and the acceleration of the maturation speed of immune cells. In addition, vitamin C is also related to the incidence of vulvar cancer and cervical cancer. Relevant data show that an increase in vitamin C intake can reduce the risk of cervical cancer.

　　3. Supplement trace elements zinc and selenium. Zinc and selenium play a crucial role in the production and function of immune cells. Scientific research shows that low levels of zinc and selenium in the body can lead to decreased immune function. It has now been found that vulvar cancer is related to trace elements zinc and selenium. The deficiency of these trace elements leads to a significant increase in the incidence of vulvar cancer, cervical cancer, and breast cancer. It is particularly important to supplement zinc and selenium in the diet.

　　4. Eat more soybeans and their products. Such as tofu, soy milk, bean curd, vegetables such as celery, broccoli, soybeans, sweet beans, and other foods. Because these foods can supplement plant estrogens, the isoflavones and lignans contained in plant estrogens are considered to have antioxidant effects by scientists.

　　Third, what foods should not be eaten for vulvar Merkel cell carcinoma

　　1. Pay attention to diet, eat less alcohol and spicy, sour, and stimulating foods.

　　2. Avoid smoking.

　　3. Avoid greasy, fried, moldy, and salted foods.

　　4. Avoid foods that are likely to cause heat, such as chicken and goose.

　　5. Avoid seafood and刺激性, allergenic foods when itching is severe.

　　First, prevention:

　　1. Pay attention to the hygiene of the vulvar area, clean the vulva with warm water every day, change underwear frequently, and avoid chronic long-term stimulation of secretions.

　　2. If nodules, ulcers, or papillary tumors are found in the vulvar area, or if there are white lesions, it is necessary to go to the hospital for a check-up in a timely manner to exclude the possibility of vulvar cancer and to receive active treatment to control the condition.

　　3. When there is vulvar itching, active diagnosis and treatment should be carried out, and it is not recommended to use strong irritant drugs for vulvar cleaning. If potassium permanganate is used for cleaning, the number of times should not be too frequent, and it should not be too concentrated.

　　4. Improve endocrine function, pay attention to the prevention and treatment of systemic diseases, regulate the overall body's physiological state, and reduce the incidence of diseases.

　　5. Middle-aged and elderly women should undergo regular gynecological examinations. For some vulvar chronic diseases that may develop into vulvar cancer, such as vulvar leukoplakia, vulvar papilloma, and others, timely and thorough treatment should be carried out, which can greatly reduce the incidence of vulvar cancer.

　　The western medical treatment method for vulvar Merkel cell carcinoma is that this disease belongs to malignant tumors and can metastasize and cause death. Therefore, it is necessary to strive for early surgical resection. For those who have recurred or have lymph node metastasis, the resection range can be expanded, and skin grafting is needed for multiple cases.

　　Secondly, for advanced patients, chemotherapy and radiotherapy can only be used.

　　1. For early-stage patients, the principle is to perform local extensive surgery to ensure negative margins. In the past, it was recommended to include normal tissue around the tumor for 2-3 cm, and the base should also exceed 2 cm, but Gillenwater et al. (2001) found that the surgical margin distance from the tumor was more than 2 cm, 1-2 cm,

　　2. The cultured Merkel cell carcinoma cells of vulvar Merkel cell carcinoma are very sensitive to radiotherapy. In head and neck Merkel cell carcinoma, Eich et al. (2002) found that the local recurrence rate and disease relief survival rate of patients who received radiotherapy after surgery were significantly lower than those who did not receive radiotherapy after surgery. Goessling et al. also suggested that 45-50 Gy of radiotherapy should be given to the primary site and involved lymph nodes after surgery, which may prevent local recurrence. Among 5 patients with vulvar Merkel cell carcinoma who received radiotherapy after surgery, except for 1 patient lost to follow-up, the others died at 5, 6, 8, and 12 months after surgery.

　　3. Chemotherapy is commonly used for metastatic lesions, with commonly used chemotherapy regimens including vincristine, doxorubicin (adriamycin), cyclophosphamide, cisplatin, and etoposide (podophyllotoxin etoposide). Because Merkel cell carcinoma is mostly found in elderly people over 60 years old, the tolerance to chemotherapy side effects is poor, especially for vulvar Merkel cell carcinoma, which is more sensitive to chemotherapy than lung, skin, and other sites. The effects of chemotherapy in 4 patients with distant metastasis were all poor.

　　4. Other growth hormone analogs such as octreotide can be used, but it is necessary to test the growth hormone receptor status before taking the medicine. Biological agents such as interferon and tumor necrosis factor are also in the clinical trial stage, and ras signal transduction inhibitors and bcl-2 antisense oligonucleotides are still in the experimental stage.