In the present case, the preoperative diagnosis was HCC because of the patient’s background chronic liver disease, elevated serum AFP and AFP-L3, and radiological findings such as high–low pattern. In hepatic IPTs, although inflammatory markers, including C-reactive protein and leukocyte count, and liver enzymes are sometimes elevated, tumor markers are usually normal [5]. AFP is a well-known tumor marker for HCC [6]. However, AFP levels also increase in non-malignant hepatic diseases such as acute/chronic hepatitis and cirrhosis, or in normal pregnancy [6, 7]. AFP-L3, an isoform of AFP, has a greater sensitivity and specificity for detecting HCC [6]. A similar case of hepatic IPT with elevated AFP and AFP-L3 levels (102 ng/mL and 85.4%, respectively) was reported [8]. However, the AFP level in the present case was approximately eight times higher than that reported in the abovementioned case. In the present case, immunohistochemical analysis showed that the tumor cells were positive for AFP, and the serum AFP level decreased dramatically to the normal level after resection of the tumor. These facts suggest that the tumor cells apparently produced AFP.
Radiological findings of IPT are also non-specific. CT scan often shows a low-density mass [3, 9,10,11]. On contrast-enhanced CT, IPT shows a variable pattern of enhancement. Generally, it shows peripheral enhancement in the delayed phase, similar to metastatic liver tumors [3, 5]. However, some studies have reported lesions with early phase enhancement and washout in the delayed phase, similar to HCC [8, 12]. The lesions in the present case also showed this pattern of enhancement. FDG-PET is not commonly performed; however, similar to the present case, there is a previous report of an IPT with abnormal metabolic activity on FDG-PET [12]. HCC is also known to have different imaging findings on FDG-PET depending on the degree of differentiation [13, 14]. In addition, hepatic IPT is usually detected as a solitary tumor [3, 5, 8, 11, 12]. In contrast, our patient had multiple IPTs in the liver, and it was reported that some patients with multiple lesions had both IPTs and malignant tumors [9]. Based on these imaging findings, we suspected intrahepatic metastasis of poorly differentiated hepatocellular carcinoma.
Once a definitive diagnosis is obtained, conservative management is the treatment of choice for IPT. However, as mentioned above, differentiating IPT from malignancy, on the basis of noninvasive diagnostic methods, is very difficult. In fact, surgical resection is frequently selected as the treatment of choice for hepatic IPTs because these tumors were suspected to be malignant tumors, preoperatively, in many cases [5, 8, 11, 15]. However, spontaneous regression has been reported in a few cases, and if this occurs, the indication for surgery should be carefully reconsidered [10]. If the patient has chronic hepatitis or cirrhosis and HCC-suspected lesion with elevated tumor markers such as AFP and AFP-L3, like the present case, the patient would be recommended surgical resection. However, we should keep in mind the possibility of benign tumors such as IPT. Although preoperative diagnosis of IPT is very difficult at this point, a careful clinical examination with the recognition of the possibility of IPT may help prevent unnecessary or at least, excessive surgical intervention.