Surgical Pathology Criteria–

Inclusion Body Fibromatosis (Infantile Digital Fibroma)

Differential Diagnosis

Infantile Fibromatosis Inclusion Body Fibromatosis
Rare in hand Vast majority in hands or feet
Usually >2 cm Rarely >2 cm
Involves skeletal muscle Muscle not involved
No inclusions Inclusions usually present

 

Fibrous Hamartoma of Infancy Inclusion Body Fibromatosis
Not reported in digits Vast majority in hands or feet
Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells Lacks triphasic pattern
No inclusions Inclusions

 

Fibroma of Tendon Sheath Inclusion Body Fibromatosis
Most common in adults Vast majority very young
Usually densely collagenized Usually cellular
No inclusions Inclusions usually present

 

Palmar or Plantar Fibromatosis Inclusion Body Fibromatosis
Usually in palm or sole Usually on digits
Uncommon in children Vast majority very young
No inclusions Inclusions

 

Infantile Fibrosarcoma Inclusion Body Fibromatosis
Rare in hand Vast majority in hands or feet
Usually >2 cm Rarely >2 cm
No inclusions Inclusions

 

Nodular Fasciitis Inclusion Body Fibromatosis
Rare in hands and feet Vast majority in hands or feet
Uncommon in children Vast majority very young
No inclusions Inclusions

 

Myofibroma Inclusion Body Fibromatosis
Rare on digits Usually on digits
Biphasic nodules with central primitive cells Lacks primitive cells and perivascular clustering of cells
No inclusions Inclusions

 

Neurofibroma Inclusion Body Fibromatosis
S100 positive S100 negative
No inclusions Inclusions

 

Leiomyoma Inclusion Body Fibromatosis
Abundant fusiform cytoplasm Scant cytoplasm
No inclusions Inclusions

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