title: Unusual sinonasal small-cell neoplasms following radiotherapy for bilateral retinoblastomas.
abstract: Two patients developed sinonasal small-cell neoplasms that arose 22 years and 37 years, respectively, following radiotherapy for bilateral retinoblastomas. The tumors were composed of small cells with scant cytoplasm and had a few scattered Homer-Wright rosettes. Immunohistochemically, one tumor was positive for keratin (CAM 5.2 and AE1/AE3), epithelial membrane antigen, and neuron-specific enolase. The other neoplasm was immunoreactive for keratin (CAM 5.2 only) and neuron-specific enolase; it also had focal immunopositivity for S-100 protein, desmin, and muscle-specific actin. Both were negative for CEA, vimentin, melanocyte-specific antigen (HMB45), chromogranin A, synaptophysin, Leu-7, 200 kd neurofilament, and retinal S-antigen. Despite aggressive multimodal therapy, the patients died of metastatic tumor 7 months and 10 months following their initial diagnosis, respectively. Although osteosarcoma is the most frequent second cancer following bilateral retinoblastomas, some patients develop clinically aggressive sinonasal small-cell tumors that are difficult to place into conventional classifications. Both of our cases showed evidence of multidirectional differentiation; one tumor labeled with epithelial and neural markers, and the other expressed epithelial, neural, and myogenous antigens.
authors.affiliation: Department of Pathology, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: H F
authors.initials: HF
authors.lastname: Frierson
authors.forename: G W
authors.initials: GW
authors.lastname: Ross
authors.forename: F M
authors.initials: FM
authors.lastname: Stewart
authors.forename: S A
authors.initials: SA
authors.lastname: Newman
authors.forename: M D
authors.initials: MD
authors.lastname: Kelly
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000276:immunology / Q000473:pathology*; D009669:Nose Neoplasms / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D010255:Paranasal Sinus Neoplasms / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D012175:Retinoblastoma / Q000276:immunology / Q000473:pathology / Q000532:radiotherapy*