Distinguishing Undifferentiated Embryonal Sarcoma of the Liver from Biliary Tract Rhabdomyosarcoma: A Children's Oncology Group Study

Abstract

Morphologically, the distinction between undifferentiated embryonal sarcoma of the liver (UESL) and biliary tract rhabdomyosarcoma (RMS) can be uncertain because of some shared pathologic similarities. Patients with UESL have been consistently but erroneously enrolled in Children's Oncology Group (COG) treatment protocols because UESL was equated with RMS, despite the differing primary treatment modalities of these entities. Review of COG pathology files yielded 20 cases of UESL that were compared to 25 cases of biliary tract RMS. Clinicopathologic features including immunohistochemical staining were examined. In the UESL cases, the male:female ratio was 1:1 and the median age was 10.5 years. Histologically, hyaline globules and diffuse anaplasia were consistently present. The cases of RMS had a male:female ratio of 1.8:1 with a median age of 3.4 years and routinely lacked diffuse anaplasia and hyaline globules. Polyclonal desmin and muscle-specific actin were variably immunoreactive in UESL and RMS; however, myogenin and myogenic regulatory protein D1 (MyoD1) were uniformly negative in UESL and routinely positive in the majority of biliary tract RMS. Myogenin, in particular, was highly significant (P = 0.0003) in distinguishing RMS from UESL. With a median follow-up of 8 months, 11 of 18 patients with UESL were still alive. The estimated 5-year survival for biliary tract RMS was 66%. Establishing the correct diagnosis of these distinct clinical and pathologic entities is important, as surgery alone may be curative in UESL, whereas initial chemotherapy is often recommended for the treatment of biliary tract RMS.

Multimodal therapy including liver transplantation for hepatic undifferentiated embryonal sarcoma

“…Mitotic indices are generally high, and anisonucleosis with hyperchromasia is often marked . Cytoplasmic and extracellular hyaline globules positive for periodic acid–Schiff can be seen . Immunohistochemical staining often demonstrates CD56 + , CD68 + , vimentin + , and desmin + staining .…”

“…Cytoplasmic and extracellular hyaline globules positive for periodic acid–Schiff can be seen . Immunohistochemical staining often demonstrates CD56 + , CD68 + , vimentin + , and desmin + staining . Myogenin is negative in HUES and can be used to differentiate HUES from biliary tract rhabdomyosarcoma …”

Soft Tissue Tumors of Uncertain Origin

“…Embryonal rhabdomyosarcoma of the biliary tract typically has botryoid features; a growth pattern with characteristic grape-like projections into the biliary duct lumina; a cambium layer of rhabdomyoblasts and strap cells beneath the epithelium; and reactivity for myogenin, myoD1, muscle-specific actin, and desmin [408]. Mesenchymal hamartoma displays a loose myxoid stroma populated by bland spindle or stellate cells without significant atypia or mitotic activity and arranged around benign, epithelial, ductal biliary structures that are frequently cystic.…”

Reporte de caso. Rabdomiosarcoma botrioides de la vía biliar

“…Morfológicamente, la distinción entre el sarcoma embrionario indiferenciado del hígado y un rabdomiosarcoma de la vía biliar puede ser incierta debido a algunas similitudes patológicas compartidas. El estándar del manejo es la resección quirúrgica con quimioterapia adyuvante [10][11][12][13][14] . Hay diseminación local o a los ganglios linfáticos regionales, peritoneo y omento en hasta el 30% de los casos.…”