Fibromatoses: clinical and pathological features suggestive of recurrence

Fibromatoses represent a spectrum of nonneoplastic spindle cell tumors frequently identified in childhood. Although they may be locally aggressive, they do not metastasize. The authors have reviewed their experience of these lesions in an attempt to identify clinical and pathological features suggestive of recurrence.

Clinical records and pathological specimens from 55 cases of fibromatosis diagnosed and treated at British Columbia's Children's Hospital from 1982 to 1995 were reviewed.

Thirty boys and 25 girls with ages ranging from 1 month to 14 years were identified. Eighteen tumors (33%) were congenital. Diagnoses were as follows: musculoaponeurotic fibromatosis (n = 27), infantile myofibromatosis (n = 10), Dupuytren-type fibromatosis (n = 7), fibromatosis colli (n = 7), and digital fibroma (n = 4). Clinical follow-up showed a survival rate of 98%. The single mortality occurred in an infant born with an intraabdominal visceral myofibromatosis, which proved unresectable. Fifteen cases recurred (27%), and nine cases (16%) of infantile myofibromatosis spontaneously regressed. All remaining cases were controlled successfully by surgical resection.

Clinical features suggestive of recurrence included (1) presentation at greater than 5 years of age, (2) extremity location of disease, and (3) incomplete surgical resection. Pathological features suggestive of recurrence were (1) microscopic evidence of tumor at resection margins, (2) mitotic index of 5 or more per 10 high-power fields, and (3) areas of necrosis and inflammation within the tumor.