title: Polyphenotypic small-cell orbitocranial tumor.
abstract: A male infant was born with a massive orbitocranial tumor without evidence of metastasis. On light microscopy, the histologic pattern of the tumor was that of a largely necrotic and highly undifferentiated small round cell neoplasm of uncertain origin. Ultrastructural features of the primitive cells included a rare tight junction and myofibril. Immunohistochemical studies showed positive staining for cytokeratin, vimentin, muscle-specific actin, neuron-specific enolase, and S100 protein and negativity for desmin and leukocyte common antigen. We believe this case represents an example of a polyphenotypic small-cell tumor of childhood with epithelial, rhabdomyoblastic, and neuroectodermal differentiation.
authors.affiliation: St Luke's Medical Center, Milwaukee, Wis.
authors.forename: D B
authors.initials: DB
authors.lastname: Lyon
authors.forename: R K
authors.initials: RK
authors.lastname: Dortzbach
authors.forename: E
authors.initials: E
authors.lastname: Gilbert-Barness
mesh_terms: D006801:Humans; D007124:Immunoenzyme Techniques; D007231:Infant, Newborn; D008297:Male; D008637:Mesenchymoma / Q000151:congenital / Q000473:pathology*; D009918:Orbital Neoplasms / Q000151:congenital / Q000473:pathology*; D010641:Phenotype; D012208:Rhabdomyosarcoma / Q000151:congenital / Q000473:pathology*; D012888:Skull Neoplasms / Q000151:congenital / Q000473:pathology*