OVERVIEW
Hepatic lipoma is a rare benign tumor originating from mesenchymal tissue without malignant transformation, often accompanied by cirrhosis. It is mostly seen in women over 40 years old, middle-aged and elderly obese people. Hepatic lipoma can be divided into simple lipoma, hibernoma and mixed lipoma. When mixed lipoma consists of blood vessels, smooth muscle and fat, it is also called vascular smooth muscle lipoma.
Etiology
The etiology and pathogenesis are not clear.
Symptoms
Hepatic lipoma is usually asymptomatic, mostly detected during physical examination, with epigastric discomfort only when the tumor is large, and abdominal pain may occur in a few cases due to intra-tumoral hemorrhage.
Examination
1. Laboratory examination
Liver function is normal, alpha-fetoprotein is normal, some patients have abnormal lipid metabolism.
2. Ultrasound examination
The tumor is extremely echogenic, the light spots are especially small and dense, with blood vessels passing through, sharp edges, slightly lobulated, the echo intensity of the posterior part of the tumor is obviously lower than that of the anterior part, and the attenuation of the distal part is obvious.
3.CT examination
CT can show the characteristic signs of lipoma, which can be seen as low-density shadow in the liver area, with negative CT value, usually below -20HU, clear boundary, internal uniformity and lobulation. Enhancement scan of the lesion does not strengthen, and the boundary is clearer.
4. Magnetic resonance imaging
It shows a clumped high signal on T1-weighted images and a higher signal on T2-weighted images. The signal performance is the same as that of subcutaneous adipose tissue, and the use of fat-suppressing sequence scans can help to establish the diagnosis.
5.Histopathologic examination
Hepatic lipoma is mostly an isolated nodular mass, with clear boundary, rounded shape, no envelope, and the diameter ranges from 1 to 20 cm. The tumor tissue of simple lipoma is composed of mature fat cells. Mixed angiomyolipoma and angiosmooth muscle lipoma contain thick-walled blood vessels, smooth muscle cells of different sizes, and adipocytes with varying degrees of vacuolar degeneration are seen. The tumor cells of hibernomas are larger, vacuolated degenerated, lipid-rich adipocytes, some of which transition to granular brown adipocytes, and rounded calcium salt vesicles are seen.
Diagnosis
Hepatic lipoma is usually asymptomatic, and needs to be clearly diagnosed by ultrasound, CT, magnetic resonance examination and other auxiliary examinations, of which CT examination is of great value in the diagnosis of hepatic lipoma.
Differential diagnosis
Hepatic liposarcoma should be distinguished from hepatic liposarcoma, and it is very difficult to distinguish the two imaging manifestations. Disease course Lipoma develops slowly, while liposarcoma develops rapidly. Histopathological examination of lipoma consists of differentiated mature adipocytes, while liposarcoma has immature cell differentiation, large nuclei and little cytoplasm, and the nuclei are schizophrenic.
Treatment
The treatment of this disease is mainly surgical excision. Smaller lipomas diagnosed can be temporarily observed, and if they increase significantly, they can be treated with surgery again.
Prognosis
Lipoma will not become malignant and has a good prognosis.