Mixed Transitional Liver Cell Tumor in a 23-Year-Old Female: A Case Report

Hepatocellular Malignant Neoplasm, Not Otherwise Specified: A New Name in Liver Tumors: A Brief Narrative Review of Published Cases

Background

Hepatocellular malignant neoplasm, not otherwise specified (HEM, NOS), is a rare liver tumor that is most commonly seen in adolescents. To the best of our knowledge, there has been no published review on this rare tumor in the English literature so far.

Summary

In this review, we will discuss all reported details, including demographic findings, clinical presentations, molecular histogenesis, imaging, gross pathology and histopathology, immunohistochemical findings, treatment modalities, and outcome, of the published cases of HEM, NOS, in the liver.

Key Message

Twenty-two cases of HEM, NOS, have been reported in the last 10 years in the English literature. This tumor produces a large liver mass and is characteristically seen in adolescents presenting with right upper quadrant pain. Histologically, HEM, NOS, is a nonbiliary hepatocytic tumor with a biphasic pattern, that is, a mixture of 2 components of hepatocellular carcinoma and hepatoblastoma (HBL). There is no characteristic immunohistochemical feature for this tumor. Imaging findings are also not specific. Treatment of this tumor needs extensive surgery or even liver transplantation. Most of the cases in the literature were treated with the primary diagnosis of HBL, so pathologists, onco-surgeons, and oncologists should get familiar with this tumor to provide better treatment options. More case series with more follow-ups are necessary for the definite determination of the outcome of this tumor as a unique entity.

Hepatocellular malignant neoplasm, NOS: a clinicopathological study of 11 cases from a single institution

AIMS

The primary aim of this study is to characterize hepatocellular malignant neoplasm, NOS (HEMNOS), a new provisional entity describing a subset of paediatric hepatocellular tumours, which have histological features of neither typical hepatoblastoma (HB) nor hepatocellular carcinoma (HCC).

METHODS AND RESULTS

The clinicopathological features of 11 patients with HEMNOS were analysed retrospectively. The median age and serum alpha-fetoprotein level at diagnosis was 7 years and 182 000 ng/ml, respectively. Ten patients presented with pretreatment extent of disease (PRETEXT) stages III/IV multifocal tumours, eight with major vascular involvement, three with lung metastases and three with extrahepatic extension. The original pathology diagnoses were: HB in seven patients, HCC in two and HEMNOS in two. Our pathology review of pre-chemotherapy specimens showed that six tumours had equivocal/overlapping histological features of HB and HCC, four had predominant HB histology along with focal HCC-like histology and one had HB histology. Seven of nine post-chemotherapy resection specimens showed predominant HCC-like histology. Beta-catenin, glypican 3 and spalt-like transcription factor 4 immunostaining showed that all the tumours had a mixed HB/HCC immunophenotype. Telomerase reverse transcriptase immunostaining showed nuclear staining in nine of the 11 tumours. All patients received chemotherapy and achieved gross total primary tumour resection. Nine of the 11 patients were treated with established HB chemotherapy regimens. After a median follow-up of 6.1 years (range: 1.2-11.8 years), all patients were in remission.

CONCLUSIONS

HEMNOS is a subtype of HB with focal HCC-like histology, a high-risk clinical profile but favourable outcome following chemotherapy and complete tumour resection.