SUBDIAPHRAGMATIC AND INTRATHORACIC PARASPINAL MALIGNANT PERIPHERAL-NERVE SHEATH TUMORS - A CLINICOPATHOLOGICAL STUDY OF 25 PATIENTS AND 26 TUMORS

BACKGROUND. To determine the effects of anatomic site on the presentat ion and diagnosis of malignant peripheral nerve sheath tumors (MPNSTs) and on the treatment and outcomes of the patients, the authors initia ted a study of these tumors at different sites. An earlier report desc ribed MPNSTs of the buttock and lower extremity, and the current serie s analyzes those presenting at intrathoracic (IT) and subdiaphragmatic (SD) paraspinal sites. METHODS. The authors reviewed data on patients with paraspinal MPNSTs who were seen at Memorial Hospital during the period 1960-1995 and for whom histologic slides were available. Variou s clinicopathologic parameters and their effects on patient outcomes w ere examined. RESULTS. Twenty-five patients with 26 tumors were evalua ted. Seven tumors were IT and 19 were SD; 60% of the patients had neur ofibromatosis type 1 (NF1). Most patients presented with pain, and a d iagnostic delay (of 3 months to 2 years) was often noted. Mean tumor s izes for SD and IT tumors were 14.3 cm and 6.6 cm, respectively. Most MPNSTs were composed of spindle cells in fascicles. Twenty seven perce nt exhibited divergent differentiation. Twenty-four tumors were high g rade, and a low grade component was identified in 8 tumors. Surgical r esection was attempted for 23 tumors (88%), but complete resection was achieved in only 6 cases (23%). Eighty percent of the patients died o f their tumors, 2-year and 5-year survival rates were 35% and 16%, and median survival was 8.5 months. Significant prognostic factors were t umor size <5 cm, the presence of a low grade component, and complete t umor resection. CONCLUSIONS. Paraspinal MPNSTs have more aggressive be havior than peripherally located tumors, mainly because of the difficu lty encountered in resecting them completely. Prognoses of patients wi th MPNST at this site appear to be affected by resection status, tumor size, and tumor grade. (C) 1998 American Cancer Society.