Esthesioneuroblastoma and Sinonasal Undifferentiated Carcinoma: Impact of Histological Grading and Clinical Staging on Survival and Prognosis

Abstract

Hyams proposed a histological grading system for esthesioneuroblastoma in which grade I tumors have an excellent prognosis and grade IV tumors are uniformly fatal. The Hyams grading system predated advanced craniofacial techniques, extensive use of immunohistochemistry, and the recognition of sinonasal undifferentiated carcinoma (SNUC) as a distinct entity. Therefore we aimed to determine whether Hyams classification is useful in predicting outcome for esthesioneuroblastoma and SNUC. A retrospective review of cases from 1970 to 1999. Twenty-six patients (12 with esthesioneuroblastoma and 14 with SNUC) were reviewed. The Kadish clinical stage was determined, and histopathological slides were reviewed and graded using the Hyams system. Kadish staging was available for 26 patients (2 patients with stage A tumors; 7 with stage B; and 17 with stage C). Of the 8 evaluable patients with Kadish stage A or B tumors, 6 remained disease free for more than 2 years compared with only 5 of the 17 Kadish stage C tumors. Slides were available for Hyams grading in 21 patients (2 patients with grade I tumors; 4 with grade II; 4 with grade III; and 11 with grade IV). Of the 6 patients with Hyams grade I or II tumors, 4 remained disease free for more than 2 years compared with only 4 of the 15 patients with Hyams grade III or IV tumors. Of note, three patients with Kadish stage C tumors (two with esthesioneuroblastoma, one with SNUC) and two patients with Hyams grade IV tumors (one with esthesioneuroblastoma and one with SNUC) survived for more than 5 years. Both the Hyams grading system and the Kadish staging system can be used as independent predictors of outcome. Although limited by small numbers, the results of this study demonstrate that patients with either advanced clinical stage or pathological grade of esthesioneuroblastoma or SNUC have poor prognosis, but that long-term survival is possible in these patients if aggressive treatment is used.