Stanford School of Medicine
Surgical Pathology Criteria
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Calcifying (Juvenile) Aponeurotic Fibroma


  • 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
  • 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


Supplemental studies


Vimentin positive
Smooth muscle actin, muscle specific actin variable
CD99 positive
CD68 positive
S100 positive
EMA variable
CD34 variable
CD57 variable
Beta-catenin negative
Most data based histologically typical cases in unusual sites
No series of cases in hands or feet have been published

Differential diagnosis

Fibrous Hamartoma of Infancy Calcifying Aponeurotic Fibroma
Nodules of immature mesenchyme No immature mesenchyme
No palisaded pattern Palisaded cells around nodules
No cartilage or calcification Cartilage and calcification
Never on hands or feet Frequent on hands and feet


Infantile Desmoid Fibromatosis Calcifying Aponeurotic Fibroma
Not nodular Nodular
No cartilage or calcification Cartilage and calcification
Usually fat in center of lesion Fat at periphery
Never on hands or feet Frequent on hands and feet


Palmar or Plantar Fibromatosis Calcifying Aponeurotic Fibroma
Rare under 20 Predominantly <20
Not calcified Calcified
Rarely chondroid Chondroid
No muscle or nerve infiltration May infiltrate muscle and nerve


Chondroma Calcifying Aponeurotic Fibroma
Predominantly adults Predominantly <20
No surrounding epithelioid cells Epithelioid cells around nodules
No muscle or nerve infiltration May infiltrate muscle and nerve


Calcifying Aponeurotic Fibroma Calcifying Fibrous Pseudotumor
Cellular lesion Paucicellular
Frequent chondroid stroma No chondroid stroma
Restricted to hands and feet Widely distributed
Broader areas of calcification Focal small calcifications


  • Age range birth to 64 years but rare over age 20 years
  • Primarily occurs on hands and feet
    • Fingers, palm, wrist
    • Plantar foot and ankle (rare on toes)
    • Infrequently seen on arms, legs, back 
  • Frequently recurs but not destructively
    • Does not metastasize


Predominantly Pediatric Fibrous Lesions


  • Kempson RL, Fletcher CDM, Evans HL, Henrickson MR, Sibley RS. Tumors of the Soft Tissues, Atlas of Tumor Pathology, AFIP Third Series, Fascicle 30, 2001
  • Fletcher CDM, Unni KK, Mertens F. Pathology and Genetics of Tumours of Soft Tissue and Bone, World Health Organization Classification of Tumours 2002
  • Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 4th edition, 2001
  • Fetsch JF, Miettinen M.  Calcifying aponeurotic fibroma: a clinicopathologic study of 22 cases arising in uncommon sites.  Hum Pathol 1998 Dec;29(12):1504-10
  • Alho A, Skjeldal S, Pettersen EO, Melvik JE, Larsen TE.  Aneuploidy in benign tumors and nonneoplastic lesions of musculoskeletal tissues.  Cancer 1994 Feb 15;73(4):1200-5
  • Lafferty KA, Nelson EL, Demuth RJ, Miller SH, Harrison MW.  Juvenile aponeurotic fibroma with disseminated fibrosarcoma.  J Hand Surg [Am] 1986 Sep;11(5):737-40
  • Allen PW, Enzinger FM.  Juvenile aponeurotic fibroma.  Cancer 1970 Oct;26(4):857-67
  • Goldman RL.  The cartilage analogue of fibromatosis (aponeurotic fibroma).  Further observations based on 7 new cases.  Cancer 1970 Dec;26(6):1325-31
  • Thway K, Gibson S, Ramsay A, Sebire NJ. Beta-catenin expression in pediatric fibroblastic and myofibroblastic lesions: a study of 100 cases. Pediatr Dev Pathol. 2009 Jul-Aug;12(4):292-6.
  • Thway K, Fisher C, Sebire NJ. Pediatric fibroblastic and myofibroblastic lesions. Adv Anat Pathol. 2012 Jan;19(1):54-65.

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