Surgical Pathology Criteria–

Giant Cell Fibroblastoma

Differential Diagnosis

Fibrous Hamartoma of Infancy Giant Cell Fibroblastoma
Triphasic with mature spindled fibroblasts, nodules of immature cells and fat Lacks triphasic pattern
Lacks giant cells Prominent giant cells
Lacks pseudovascular spaces Prominent pseudovascular spaces

 

Angiosarcoma Giant Cell Fibroblastoma
Cytologically atypical Giant cells appear multinucleated rather than cytologically atypical
Anastomosing vascular channels Irregular pseudovascular spaces
Tufted endothelial growth is frequent Lacks tufted pattern
May be mitotically active Mitotic figures rare
Spaces lined by CD31 positive endothelium CD31 negative
Usually occurs in sun exposed skin of adults, rare in children Mean age 3-6 years

 

Myxoid Liposarcoma Giant Cell Fibroblastoma
Always involves deep soft tissue Usually involves superficial subcutaneous tissue
Frequently contains lipoblasts No lipoblasts
CD34 may stain scattered dendritic cells but not lesional cells CD34 stains lesional cells
Arborizing vascular pattern Pseudovascular spaces
Lacks giant cells Frequent giant cells

 

Plexiform Fibrohistiocytic Tumor Giant Cell Fibroblastoma
Ray-like extension of fibrous tissue into surrounding fat Infiltrates between and around individual fat cells
Lacks pseudovascular spaces Pseudovascular spaces present
Nodules of histiocytes and giant cells in most cases Scattered individual giant cells
CD34 negative CD34 stains lesional cells

 

Myxofibrosarcoma Giant Cell Fibroblastoma
Usually seen in adults, rare under 20 Mean age 3-6 years
Cytologically atypical but no multinucleated giant cells Giant cells appear multinucleated rather than cytologically atypical
May be mitotically active Mitotic figures rare
Lacks pseudovascular spaces Pseudovascular spaces present

 

Atypical Deep Fibrous Histiocytoma Giant Cell Fibroblastoma
Lacks pseudovascular spaces Pseudovascular spaces present
CD34 negative CD34 stains lesional cells

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