OVERVIEW
Malignant fibrous histiocytoma is the most common type of adult soft tissue sarcoma, occurring most commonly in the deep soft tissues and skeletal muscles of the limbs and trunk, with liver origin being extremely rare. Its nature and origin are not well understood; since the first case was reported by Conran et al. in 1985, there has been little international research on how it occurs in the liver. The clinical manifestations of hepatic malignant fibrous histiocytoma are mainly epigastric pain, abdominal mass, ascites, emaciation, or low-grade fever, and its malignancy is high with poor prognosis.
Etiology
The cause is unknown and may be related to factors such as radiation exposure.
Symptoms
The main clinical manifestations include fatigue, loss of appetite, weight loss, low-grade fever, epigastric pain or masses. The duration of the disease varies, and may extend for several weeks to several years.
Examination
1. Laboratory tests
White blood cell count may be elevated, alkaline phosphatase level is elevated, and alpha-fetoprotein level is normal.
2. CT examination
The tumor has obvious outward infiltration, unclear boundary, significant necrosis inside the tumor, small proportion of parenchyma, and common intratumoral hemorrhage. There is enhancement in both arterial and portal venous stages, but the density is lower than that of normal liver tissue. The liver tissue around the tumor in the arterial stage is temporarily increased in density, and the tumor is regressed to isodensity in the portal venous stage.
3.Ultrasonography
It can be seen that the mass has clear margins and irregular shape, and its internal structure has different echoes according to the tissue composition of the parenchyma and the degree of liquefaction and necrosis, mostly showing mixed echoes, and liquid dark area can also be seen.
4.Pathologic examination
Tumor cells are arranged in the shape of spokes; tumor cells are moderately heterogeneous, and multinucleated tumor giant cells and vacuolated cells can be seen. The size and morphology of the nuclei of tumor cells in some patients are obviously heterogeneous.
Diagnosis
The clinical manifestations of this disease are atypical, and it is difficult to differentiate it from hepatocellular carcinoma; CT or ultrasound-guided puncture biopsy is limited in sampling, and it is difficult to make preoperative diagnosis. Clinically, it manifests epigastric pain, abdominal mass, ascites, wasting or low fever, and ultrasound and CT can make preliminary judgment on it based on the features of huge liver mass, more or less intratumoral hemorrhagic necrotic foci, tumor invasion of hepatic peritoneum or even invasion of neighboring tissues, and the absence of intratumoral calcified foci and local lymph node metastasis. The diagnosis was mainly based on post-surgical pathological histologic examination. Pathological and histological examination showed spindle-forming fibroblast-like cells and histiocyte-like cells, which were arranged in bundles or wheels.
Differential diagnosis
1. Hepatocellular carcinoma
Hepatocellular carcinoma has intensification in arterial stage, and most of the intensification in portal stage decreases significantly to low density, which is characterized by “fast in, fast out”, and patients often have the history of hepatitis B, and have the manifestation of cirrhosis on CT, so it is easy to differentiate.
2.Liver abscess
Malignant fibrous histiocytoma of liver can be misdiagnosed as liver abscess when necrosis and cystic degeneration are obvious, but liver abscess usually has obviously strengthened ring-shaped abscess wall, surrounded by low-density edema, central low-density necrotic tissues, presenting tricirclic changes, and there can be gas in the abscess cavity, and there are often chills and high fever in clinical manifestations.
3. Hepatic cystadenocarcinoma
Malignant fibrous histiocytoma of liver is easily diagnosed as hepatic cystic adenocarcinoma when necrosis and cystic changes are obvious. Cystic adenocarcinoma is usually multilocular, and segments and soft tissue wall nodules can be seen inside the cyst, the cystic wall and the wall nodules are obviously strengthened in arterial phase of enhancement scan, and the degree of strengthening is reduced in portal phase of enhancement scan.
Treatment
Surgery is the most effective way to treat this disease. In order to minimize the recurrence rate, adequate surgical border resection should be achieved at the time of primary treatment. Radiotherapy is effective in reducing recurrence and improving survival, and can generally be administered intraoperatively or as postoperative adjuvant radiotherapy. Chemotherapy is effective for malignant fibrous histiocytomas but is not specific enough to eliminate microscopic residual and microscopic metastases.