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

Abstract

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.

Incidence and 5‐year survival of children and adolescents with hepatoblastoma in the United States

“…Five‐year overall survival increased during 2001–2016, and survival for cases diagnosed at earlier ages had better overall 5‐year survival outcomes when compared to cases involving individuals older than 7 years of age. This survival difference may be related to the poor responsiveness to chemotherapy of specific subsets of HBs, including the recently recognized entity “hepatocellular neoplasm, not otherwise specified.” This subtype includes biphasic features of both HB and hepatocellular carcinoma and is more prevalent in older patients 26–28 . As established in prior studies, age and stage at diagnosis remain amongst the most significant factors impacting case survival 1,2 .…”

“…This subtype includes biphasic features of both HB and hepatocellular carcinoma and is more prevalent in older patients. [26][27][28] As established in prior studies, age and stage at diagnosis remain amongst the most significant factors impacting case survival. 1,2 Overall survival outcomes significantly improved between 2001 and 2016 when comparing 5-year outcomes before and after January 1, 2010.…”