Calcifying (Juvenile) Aponeurotic Fibroma
Definition
- Pediatric lesion composed of cellular nodules with central chondroid differentiation and calcification
Alternate / Historical Names
- Juvenile nodular aponeurotic fibroma
- Keasbey tumor
Diagnostic Criteria
- Primarily occurs in hands and feet
- Infrequently on back, legs and arm
- Generally under 3 cm
- Rarely up to 5 cm
- Fibrous tissue surrounds cellular nodules with central chondroid tissue and calcification
- Fibrous tissue
- Dense, paucicellular with small mature spindled fibrocytes
- May infiltrate surrounding muscle, nerves and fat
- Cellular nodules
- Variable cellularity
- Plump oval vesicular nuclei
- Cells frequently epithelioid
- Cells tend to palisade around centers
- Centers of nodules frequently show chondroid differentiation
- Amorphous calcification in centers very commonn
- May be lacking in infants and very young children
- May ossify with osteoclast-like giant cells in older children
- Fibrous tissue
- Two cases described with development of fibrosarcoma
Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates: 1/20/07, 3/16/08, 1/29/12
