Undifferentiated Embryonal Sarcoma of the Liver Presents as a Molecular Mimic of Parasitic Infection

Abstract

Medical laboratory tests are becoming more reliable with increased specificity and sensitivity, leading to their use as definitive diagnostic tests for many medical conditions. Enzyme-linked immunosorbent assay (ELISA) tests are convenient, sensitive, and standardly used for rapid detection and quantification of antigens or patient antibodies against specific antigens. However, based upon the specificity and sensitivity of an ELISA test, the results may not be definitive for a specific disease but merely suggestive, due to potential cross-reactivity of antigens and antibodies. Here, we present a case of a 15-year-old male who presented with fever, nausea, and right upper quadrant pain. Computed tomography scan showed an 18-cm liver mass with cystic features. Biopsy results confirmed a diagnosis of undifferentiated embryonal sarcoma of the liver; however, the clinical picture was complicated by positive ELISA results for Echinococcus, Entamoeba histolytica, and histoplasmosis. Due to the absence of travel and positive ELISA result for three different infectious agents, we hypothesize that tumor molecular mimicry might have led to false-positive ELISA results in the absence of infection in this case, demonstrating a limitation of ELISA serology. Critical appraisal of all possible evidence to ensure alignment when assigning the final diagnosis is essential for optimal patient outcomes.

Update on the Pathology of Pediatric Liver Tumors: A Pictorial Review

“…CT scans on the other hand show a predominantly cystic, hypoattenuated mass because the gel-like myxoid stroma has a water-like density when using CT. This discrepancy of a predominantly solid mass upon ultrasound and cystic mass upon CT is diagnostic of embryonal sarcoma [99,100]. Another characteristic feature is the presence of serpiginous vessels in the tumor in CT scans.…”

Pediatric Primary Hepatic Tumors: Diagnostic Considerations

“…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 ].…”

“…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 ]. Zhang et al reported a case of a nine-year-old female with elevated IgE and transient peripheral eosinophilia, initially misdiagnosed as Echinococcus [ 165 ].…”

Neurocysticercosis: Autoantibodies, Another Cog in the Wheel of Its Variable Pathogenicity

“…A crucial question for the future is to define mechanisms of molecular mimicry that exist between Taenia solium and neuronal antigens. At present, the only relevant observations are tenuous: (1) "Glycan mimicry" in many helminths, including Echinococcus granulosus and T. solium [7], (2) 94 tapeworm protein sequences with bioinformatic similarities to stickleback proteins [8] and (3) False positive ELISA's for E. granulosus with patients presenting with an undifferentiated embryonic sarcoma of the liver, interpreted as evidence for the molecular mimicry hypothesis [9].…”