Gardner-associated Fibroma

Definition

Hypocellular collagenous lesion with surrounded fat similar to nuchal-type fibroma but occurring in children or in extra-nuchal sites

Histologic features similar to nuchal-type fibroma
- Not encapsulated, radiates into fat
  - Frequent entrapped fat
- Subcutaneous component in all cases
- Paucicellular formless sheets of collagen
  - Few, small fibrocytes
- Rare entrapped nerves
  - Lacks traumatic neuroma like pattern
- Infrequent infiltration of skeletal muscle
Most located on trunk
- Also head and neck, extremites
May be associated with Gardner syndrome
- Such lesions in extra-nuchal sites should prompt clinical investigation for Gardner syndrome
  - Found in 70%
  - This may be the presenting finding
Beta-catenin positive in 64%
Recurrence appears to be more common than with nuchal-type fibroma
- Recurrences may be as desmoid type fibromatosis (20%)
Gardner syndrome
- Familial adenomatous polyposis
- Osteomas, especially of mandible
- Mesenteric, and rarely abdominal, fibromatosis
- Cutaneous epidermoid cysts

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting : November 20, 2007
Last Update: December 22, 2008