Surgical Pathology Criteria

Nuchal-type Fibroma

Differential Diagnosis

Gardner Associated Fibroma Nuchal-type Fibroma
Age range 2 mo to 36 years Age range 3 to 74 years
Most, but not all cases, extranuchal 70% nuchal
Formless sheets of collagen Thick bundles of collagen
Rare entrapped nerves Frequent entrapped traumatic neuroma areas
The two may be very difficult to distinguish histologically

 

Nuchal-type Fibroma Fibrolipoma
Radiates into fat Encapsulated
Abundant collagen Focal collagen
Frequent entrapped nerves Lacks entrapped nerves

 

Nuchal-type Fibroma Elastofibroma
Elastic fibers not prominent Prominent abnormal elastic fibers
Subcutaneous component in all cases Deep, subscapsular

 

Nuchal-type Fibroma Extra-abdominal Desmoid Fibromatosis
Involves superficial tissues Involves deep tissues
Infrequently involves skeletal muscle Involves skeletal muscle
Paucicellular May have cellular areas

 

Nuchal-type Fibroma Solitary Fibrous Tumor
Paucicellular May have cellular areas
Radiates into fat Usually circumscribed
Inconspicuous vessels Frequent stag horn vessels

 

Nuchal-type Fibroma Spindle Cell Lipoma
Radiates into fat Encapsulated
Abundant collagen Focal collagen
Frequent entrapped nerves Lacks entrapped nerves

 

Nuchal-type Fibroma Scar
No history of trauma History of trauma
These two may be histologically indistinguishable

 

Nuchal-type Fibroma Fibrous Hamartoma of Infancy
Lacks triphasic pattern, no immature component Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells
Most age 20 to 40, unless associated with Gardner syndrome Age range congenital to 4 years
Typically located in or near posterior neck Usually axillary or inguinal

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