Differential Diagnosis of Hepatic Mass with Central Scar: Focal Nodular Hyperplasia Mimicking Fibrolamellar Hepatocellular Carcinoma

Fibrolamellar hepatocellular carcinoma is a primary hepatic tumor that usually appears in young adults. Radical surgery is considered curative for this kind of tumor, so early diagnosis becomes essential for the prognosis of the patients. The main characteristic of this entity is the central scar, which is the center of differential diagnosis. We report the case of a 30-year-old man who was diagnosed with fibrolamellar hepatocellular carcinoma by ultrasonography. Contrast-enhanced CT confirmed this diagnosis, and the patient underwent a [18F] fluorocholine PET/CT. Hypermetabolism and the morphology in the nuclear medicine exploration suggest neoplastic nature of the lesion. Radical surgery was performed, and histopathologic analysis was performed, which resulted in focal nodular hyperplasia. Hepatic masses with central scar could have a difficult differential diagnosis, and focal nodular hyperplasia could mimic fibrolamellar hepatocellular carcinoma imaging patterns. These morphofunctional characteristics have not been described in [18F] Fluorocholine PET/CT, so there is a need to find out the potential role PET/CT in the differential diagnosis of hepatic mass with central scar.

Fibrolamellar Hepatocellular Carcinoma: Report of a Rare Case with Rapid Progression and Unusual Metastatic Sites

Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare primary liver cancer that occurs in young adults, and its biology is not well known. We present a 21-year-old woman with metastatic liver cancer 6 months after undergoing embolization procedures for a typical hemangioma. The pathological investigation confirmed metastatic FLHCC. Despite liver mass resection and lung metastasectomy, after 3 months, the tumor recurred. In 18F-FDG PET-CT scan, lung, ovary, colon, and peritoneal invasions were reported. Unfortunately, the patient died a year after diagnosis due to a rapid progression and multiple unusual metastatic sites.

Prognostic value of the proportion of the sclerosing component in fibrolamellar liver carcinoma

Introduction. Fibrolamellar hepatocellular carcinoma (FLC), which develops most often in the younger population. In FLC, variable histoarchitectonics are noted, possibly the presence of a sclerosing component, foci of necrosis and dystrophy of tumor cells.Objective. Assessment of the influence of the proportion of the sclerosing component in fibrolamellar carcinoma (FLC) of the liver on the course and prognosis of the disease. Determination of the relationship between the proportion of the sclerosing component in the tumor and the frequency of microvascular invasion.Materials and methods. A retrospective study included 34 patients with a diagnosis of FLC, who underwent radical surgical treatment at the first stage. A histological assessment of the proportion (%) of the sclerosing component in FLC was made. The effect of the proportion of the sclerosing component on overall (OS) and relapse-free (DFS) survival was assessed. The analysis of the relationship between the proportion of the sclerosing component in the tumor and the frequency of microvascular invasion was carried out.Results. Significantly worse RFS was achieved in the groups of patients with a sclerosing component in FLC > 5% than in the group of patients with a sclerosing component in FLC ≤ 5% (p = 0.0010; p = 0.024; log – rank test). Median DDS in group 1 is 107 (95% CI, 22–192) months; at 2 – 11 (95% CI, 8–14) months; in 3 – 21 (95% CI, 8–33). The frequency of histologically confirmed microvascular invasion in the compared groups was 29, 74, 87.5%, respectively. OS was significantly worse in 2 groups (27 patients in total) with a sclerosing component in FLC > 5% than in the group of patients with a sclerosing component in FLC ≤ 5%. Median OS in group 1 120 (95% CI, 60–180) months; at 2 – 41 (95% CI, 15–92) months; in 3 – 69 (95% CI, 35–103). A direct relationship was found between an increase in the proportion of the sclerosing component in a tumor and an increase in the frequency of microvascular invasion.Conclusions. We can assume that the severity of the sclerosing component in the FLK tumor can serve as an effective morphological marker of a less favorable prognosis for this HCC subtype and correlate with the frequency of microvascular invasion.

A case report of fibrolamellar hepatocellular carcinoma, with particular reference to preoperative diagnosis, value of molecular genetic diagnosis, and cell origin

Background Fibrolamellar hepatocellular carcinoma (FL-HCC) is a liver tumor that occurs almost exclusively in young adults without underlying liver disease. In spite of its distinct clinical characteristics and specific imaging findings, preoperative diagnosis is often difficult due to the extremely low incidence of the tumor. Although FL-HCC shows particular morphological features on H&E-stained tissue sections, differential diagnosis from ordinary HCC, especially the scirrhous variant of HCC, and intrahepatic cholangiocarcinoma needs additional immunohistochemical (IHC) analyses and/or molecular genetic testing. Case presentation A 21-year-old male patient was referred to our hospital for further evaluation of a large liver mass. Abdominal ultrasound examination, contrast-enhanced computed tomography, and magnetic resonance imaging revealed a well-defined hypervascular lobulated liver mass, 11 × 11 cm in diameter, with a central scar and calcification, in segments 5/8. Under the diagnosis of FL-HCC, we carried out extended anterior sectorectomy, including a part of segment 4. On microscopic examination, the tumor was composed of proliferating polygonal cells with abundant eosinophilic granular cytoplasm containing nuclei with vesicular chromatin and enlarged nucleoli, in an abundant stroma. Collagen fibers arranged in a parallel lamellar pattern were seen in the tumor stroma. These findings, together with the results of subsequent IHC analyses using HAS, CK7, and CD 67, we made the diagnosis of FL-HCC, which was further confirmed by detection of the DNAJB1-PRKACA fusion gene in the tumor cells by RT-PCR. Conclusion FL-HCC shows distinct imaging appearances. Although it also has characteristic morphological features, combined use of IHC and/or molecular genetic studies are necessary for the final diagnosis.

Molecular Basis of Hyperammonemic Encephalopathy in Fibrolamellar Hepatocellular Carcinoma

Purpose hyperammonemic encephalopathy is a potentially fatal condition associated with fibrolamellar hepatocellular carcinoma. The mechanism involved in hyperammonemia in patients with fibrolamellar carcinoma was unclear until a possible physiopathological pathway was recently proposed. An ornithine transcarboxylase dysfunction was suggested as a result of increased ornithine decarboxylase activity induced by c-Myc overexpression. This c-Myc overexpression resulted from Aurora Kinase A overexpression derived from the activity of a chimeric kinase that is the final transcript of a deletion in chromosome 19, common to all fibrolamellar carcinomas. Methods we performed the analysis of the expression of all enzymes involved and tested for the mutation in chromosome 19 in fresh frozen samples of fibrolamellar hepatocellular carcinoma, non-tumor liver and hepatic adenomatosis. Results specific DNAJB-PRKACA fusion protein that results from the recurrent mutation on chromosome 19 common to all fibrolamellar carcinoma was detected only in the fibrolamellar carcinoma sample. Fibrolamellar carcinoma and adenomiomatosis samples presented increased expression of Aurora Kinase A, c-MYC and ornithine decarboxylase when compared to normal liver, while ornithine transcarbamylase was decreased. Conclusion The proposed physiopathological pathway is correct and that overexpression of c-Myc may also be responsible of hyperammonemia in patients with other types of rapidly growing hepatomas. This gives further evidence to apply new and adequate treatment to this severe complication.