Pulmonary Metastases from an Undifferentiated Embryonal Sarcoma of the Liver: A Case Report and Review

Abstract

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare malignant hepatic tumor that occurs primarily in children. Only a limited number of cases have been reported in the literature due to low incidence of one per million, and reports of metastatic lesion of UESL are even rarer. We hereby describe the case of a 13-year-old male who presented with a palpable mass with imaging findings suggestive of a large complex tumor in the right lobe of the liver. He underwent extended right hepatectomy followed by adjuvant chemotherapy. The tumor was confirmed to be UESL by postoperative pathology and immunohistochemical staining analysis. Four years later, surveillance imaging revealed a small lung nodule in the left lower lobe. Complete removal of the lung tumor by wedge resection was performed, and a histological diagnosis of metastatic UESL was made. The patient also received postoperative adjuvant chemotherapy and is currently in a good general condition and tumor-free in the present eight-month period. This case is presented with emphasis on clinicopathological and immunohistochemical findings of the primary UESL and lung metastases with the aim of collecting more data and expanding our understanding of this rare malignancy.

Pediatric Primary Hepatic Tumors: Diagnostic Considerations

“…Classically, it presents in children from the age of six to ten and shows no gender predilection. It is considered to be the third most common malignant hepatic tumor in childhood, after hepatoblastoma and hepatocellular carcinoma, accounting for approximately 9–15% of all pediatric liver tumors, with an incidence of one case per million people per year [ 30 , 158 , 159 , 160 , 161 , 162 , 163 ].…”

“…The presentation is nonspecific, with abdominal pain, hepatomegaly, nausea, anorexia, and fever, and is rarely associated with jaundice [ 30 , 159 , 160 , 161 , 162 , 163 ]. The majority of patients who present are asymptomatic; however, patients may present acutely due to tumor rupture and tumor wall dehiscence secondary to rapid growth [ 163 , 164 , 165 ].…”

“…Patients may present with mild leukocytosis or leukopenia, anemia, hypoalbuminemia, mildly elevated transaminases, and inflammatory markers [ 160 , 163 , 167 ]. AFP and carcinoembryonic antigen are typically normal, although cases with elevated levels have been reported [ 159 , 160 , 161 , 163 , 164 , 165 , 168 ]. Interestingly, Letherer et al reported a case of a UESL in a 15-year-old male that caused a false positive ELISA result for Echinococcus , Entameoba histolytica , and histoplasmosis secondary to molecular mimicry [ 168 ].…”

“…The cut surface is yellow to tan with a heterogenous appearance that is predominantly solid with alternating cystic foci and areas of gelatinous degradation (corresponding to areas of myxoid histology). Necrotic and hemorrhagic areas are common [ 30 , 160 , 163 ].…”

“…This tumor demonstrates a high mitotic index, frequent atypical mitoses, and apoptotic bodies and a high Ki67 proliferation index (30%) [ 30 , 161 ]. Cytology is notable for medium to large spindle or stellate-shaped cells with ill-defined borders and inconspicuous nucleoli within a myxoid matrix or fibrous stroma [ 30 , 160 , 164 ]. Multinucleated giant cells, bizarre cells with aberrant nuclei, and eosinophilic hyaline globules (which are PAS-positive) may also be identified, which are important diagnostic clues [ 30 , 160 , 163 , 164 , 165 ].…”