Malignant fibrous histiocytoma and other fibrohistiocytic tumors in pediatric patients: The St. Jude Children's Research Hospital experience

BACKGROUND. Malignant fibrous histiocytoma (MFH) is a controversial entity. In the current study, the authors reviewed their institutional experience with these tumors to characterize their clinical features in pediatric patients and assess the impact of surgical resection on outcome. METHODS. The records of the 28 patients who were diagnosed with MFH or MFH variants of soft tissue between January 1971 and December 2000 were reviewed and the tumors were reclassified according to the World Health Organization guidelines. RESULTS. Seventeen patients had MFH; 10 patients had angiomatoid fibrous histiocytoma (FH), and 1 patient had a plexiform fibrohistiocytic tumor. The median age of patients at the time of diagnosis was 7.3 years. The most common primary tumor site was the extremity (n = 14). Metastatic disease (to the lung) was present in only three patients, each of whom had MFH. Of the 17 MFH tumors, 13 were high grade, 8 were invasive, and 6 measured > 5 cm. All angiomatoid FH tumors and the plexiform fibrohistiocytic tumor were noninvasive, and 10 measured ≤ 5 cm. Surgical treatment was comprised of wide local excision with clear margins (n = 18), amputation (n = 3), excision with positive or indeterminate surgical margins (n = 4), partial resection (n = 2), or biopsy only (n = 1). Primary reexcision was performed for 21 patients. The 5-year survival and event-free survival (EFS) estimates for patients with MFH were 76.5% ± 11.2% and 70.6% ± 12.1%, respectively; the 5-year survival and EFS estimates were 100% ± 0% for patients with angiomatoid FH or plexiform fibrohistiocytic tumor. Compared with partial resection or excision, wide local excision or amputation was found to have a positive impact on the probability of EFS in patients with localized disease (P = 0.008). All four patients with metastatic or unresectable MFH had died by the time of last follow-up. CONCLUSIONS. MFH should be distinguished from angiomatoid FH and plexiform fibrohistiocytic tumors, both of which are less aggressive. Wide local excision is the treatment of choice, regardless of the histology or grade of the tumor. Patients with metastatic or unresectable MFH appear to have a poor outcome and would benefit from more effective therapies.