Primary liver liposarcoma

　　1. Etiology

　　Liposarcoma is a common malignant soft tissue tumor that originates from mesenchymal cells during the differentiation of preadipocytes into fat cells, and therefore shows atypical fat precursor cells of different differentiation degrees, all containing lipids. According to the degree and type of differentiation of tumor cells, it can be divided into four types: well-differentiated type, myxoid type, round cell type, and pleomorphic type, but polymorphic cell mixture usually exists in tumors.

　　From the perspective of origin, liposarcoma can occur in any part where there is adipose tissue. Cases occurring in the limbs account for 60%, retroperitoneal space for 15%, subcutaneous in the trunk for 15%, and primary liposarcoma in the liver is extremely rare. To date, the number of reported primary liver liposarcomas has not exceeded 10 cases.

　　2. Pathogenesis

　　Primary liver liposarcoma is very similar in pathological morphology to liposarcoma in other parts of the body. The tumor is elliptical or irregular in shape, soft in texture, and is often not discovered until it reaches a large size. The tumor section is grayish yellow or grayish white, with frequent necrotic areas that are prone to soften and fragment. The surrounding tissue of the tumor may be compressed, forming an incomplete thin pseudocapsule. Well-differentiated liposarcomas can have a complete capsule. Under microscopic observation, the tissue of liposarcoma contains differentiated mature fat cells and mesenchymal cells at various stages of differentiation and atypical cells. The cytoplasm shows lipid droplet vacuoles, and the nucleus is elliptical or round, with coarse grains and deep staining. The myxoid type shows abundant mucoid matrix between cells, and the Alcian blue stain is positive. There is no liver cirrhosis in the surrounding liver tissue.

　　Liposarcoma is a moderately malignant tumor in soft tissue sarcomas, with a 5-year survival rate of 35% to 40%, and about 40% to 50% of liposarcomas have lung metastasis. The main age of onset is middle and late adulthood. From the 4 cases of primary liver liposarcoma reported abroad, two are middle-aged women and two are children. In China, two cases reported were both adults, one male and one female, with well-differentiated and mucinous types. Due to the lack of follow-up reports, there is a lack of information on its prognosis.

　　1. There are often symptoms such as decreased appetite, weight loss, and fatigue, and occasionally intractable hiccups.

　　2. In advanced patients, chest, abdominal, and distant metastasis can occur, as well as cachexia.

　　3. Tumor rupture and hemorrhage: The incidence rate is about 5.46% to 19.8%. The clinical manifestations of liver liposarcoma rupture and hemorrhage include upper abdominal pain. Larger hemorrhages can cause hypotension, shock, and ascites in a short period of time; if the hemorrhage is slow, the clinical symptoms may be not obvious, only manifested as anemia symptoms, and may not be discovered until imaging studies or abdominal puncture.

　　Primary liver liposarcoma has no obvious symptoms in the early stage of onset. As the tumor grows, patients may experience dull or hidden pain in the right upper quadrant, often radiating to the right shoulder. The pain is caused by the stretching of the liver capsule due to the expansive growth of the tumor. There are often symptoms such as decreased appetite, weight loss, fatigue, and occasionally intractable hiccups. Unlike other malignant tumors in the liver, patients with primary liver liposarcoma generally do not show jaundice. The reported cases of patients with large tumor volumes, generally more than 10cm×10cm×10cm, weighing several kilograms, but no jaundice has been observed. Physical examination shows that the right rib area is bulging and full, the liver volume increases significantly, the texture is softer, the edge is thick and blunt, the surface is smooth, there is no tenderness or percussion pain, and liver palms and spider nevi can be seen.

　　Since the etiology of primary liver liposarcoma is not yet fully understood, the methods of prevention are not much different:

　　1. Minimize infections, avoid contact with radiation and other harmful substances, especially drugs that suppress the immune system;

　　2. Appropriate exercise, enhance physical fitness, and improve one's ability to resist diseases.

　　Prevention mainly focuses on various factors that may lead to primary liver liposarcoma. It is believed that the loss of normal immune surveillance function, the tumor-promoting effects of immunosuppressants, the activity of latent viruses, and the long-term use of certain physical (such as radiation) and chemical (such as antiepileptic drugs, adrenal cortical hormones) substances may all lead to the proliferation of lymphoreticular tissue, eventually resulting in primary liver liposarcoma. Therefore, attention should be paid to personal and environmental hygiene, drug abuse should be avoided, and personal protection should be taken into account when working in harmful environments.

　　Primary liver liposarcoma has a late onset of liver function damage, and enzyme tests and tumor markers such as AFP, CEA are negative. Patients often present with right upper quadrant pain and are diagnosed preliminarily by imaging studies after the discovery of a large liver. However, a definitive diagnosis requires a liver biopsy.

　　The imaging manifestations of this disease are quite characteristic.

　　1. Ultrasound examination can see large and uniform strong echo areas in the liver.

　　2. CT shows clear low-density areas with a low CT value, which can reach -90Hu or more, which is the lowest CT value of liver tumors. There is no enhancement response after injection of contrast agent.

　　3. MRIT1, T2 weighted images show high signal areas.

　　It is difficult to distinguish between hepatic liposarcoma and hepatic lipoma in imaging examinations.

　　1. The diet should be light and nutritious. Eat more vegetables (such as cabbage and cauliflower), radishes, plums, soybeans, beef, mushrooms, asparagus, Coix seed, and other foods containing anticancer substances. Fruits, milk, and turtles are rich in various amino acids, vitamins, proteins, and easily digestible tonic foods.

　　2. Tumor patients have a high energy consumption, so their diet should be increased by 20% more than that of normal people.

　　3. Eat less greasy and heavy foods; eat less hot and supplementary foods such as dog meat and mutton; eat less shellfish, bamboo shoots, taros, and other easily allergic "mushrooms" without shells; eat less drinks and snacks containing chemicals, preservatives, and additives. Avoid foods that are too sour, spicy, salty, and stimulants such as tobacco and alcohol.

　　1. Treatment

　　Surgery is the main method of treatment for hepatic liposarcoma. Well-differentiated hepatic liposarcoma with good prognosis after surgical resection of the primary tumor. A case reported in China shows that a patient who underwent surgical resection of a primary tumor with a volume of 20cm×20cm×25cm had no recurrence and good quality of life after half a year of follow-up. Another patient with mucinous type had recurrence of the disease 4 months after surgery and died without treatment. Chemotherapy, radiotherapy, and traditional Chinese medicine treatment can be used as auxiliary methods in comprehensive treatment plans. Liposarcoma is not very sensitive to chemotherapy, but if the patient has distant metastasis and loses the opportunity for surgery, chemotherapy is the first choice. Commonly used drugs include cisplatin, 5-FU, dithiocarb (DITC), doxorubicin, etc. Radiotherapy is an effective measure to relieve pain when the sarcoma has bone metastasis.

　　2. Prognosis

　　The progression of this disease is relatively slow, and it rarely occurs metastasis. If it can be surgically removed, the life of the patient can be extended.