title: Fibromyxoid areas and immature osteoid are associated with recurrence of primary aneurysmal bone cysts.
abstract: OBJECTIVE
  Primary aneurysmal bone cysts have a high recurrence rate following curettage. The aim of this study was to determine clinicopathological features associated with recurrence of aneurysmal bone cysts.
  
  
  RESULTS
  The clinicopathological features of 86 patients (37 males, 49 females, age range 5-62 years) with aneurysmal bone cysts were reviewed. Recurrence rates following curettage and excision were 32.7% and 5.6%, respectively (P = 0.028). The association of clinicopathological features with recurrence was studied in a subset of 45 patients treated by curettage. The presence of nodular fasciitis-like fibromyxoid areas [P = 0.033, odds ratio (OR) = 9.17, 95% confidence interval (CI) 1.06, 79.39] and immature osteoid with active osteoblasts (P = 0.041, OR = 3.7, 95% CI 1.03, 13.35) was significantly associated with an increased risk of recurrence. Clinical and radiological features were not associated with recurrence. In a multivariate analysis, the presence of immature osteoid was a better predictor of recurrence than radiological activity (hazard ratio = 3.18, 95% CI 1.04, 9.73, P = 0.043). There was no statistically significant association between radiological activity and histological features.
  
  
  CONCLUSIONS
  Aneurysmal bone cysts with nodular fasciitis-like fibromyxoid areas and immature osteoid with active osteoblasts are more likely to recur. Mention of these features in histopathology reports will help to identify patients who require closer follow-up. Lesions that are apparently radiologically inactive may show fibroblastic and osteoblastic proliferation and therefore may recur.
authors.affiliation: University Department of Pathology/Scottish Bone Tumour Registry, Western Infirmary, Glasgow, UK.
authors.forename: M V C
authors.initials: MV
authors.lastname: de Silva
authors.forename: N
authors.initials: N
authors.lastname: Raby
authors.forename: R
authors.initials: R
authors.lastname: Reid
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017824:Bone Cysts, Aneurysmal / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005208:Fasciitis / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000378:metabolism* / Q000473:pathology; D010012:Osteogenesis; D011859:Radiography; D012008:Recurrence