Fibrous Hamartoma of Infancy
Differential Diagnosis
- Infantile fibromatosis
- Fibrolipoma
- Calcifying aponeurotic fibroma
- Myofibroma
- Rhabdomyosarcoma
- Infantile fibrosarcoma
- Inclusion body fibromatosis
- Gardner associated fibroma
| Fibrous Hamartoma of Infancy | Infantile Fibromatosis |
|---|---|
| Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells | Not triphasic |
| Primarily superficial | Usually centered on muscle |
| Fibrous Hamartoma of Infancy | Fibrolipoma |
|---|---|
| Poorly circumscribed | Encapsulated |
| Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells | No immature component |
| 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 |
| Fibrous Hamartoma of Infancy | Myofibroma |
|---|---|
| Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells | Biphasic lesion with outer spindled cells and inner immature cells |
| Lacks hemangiopericytomatous vessels | Hemangiopericytoma-like vessels frequent |
| Rare mitotic figures | Frequent mitotic figures |
| Fibrous Hamartoma of Infancy | Rhabdomyosarcoma |
|---|---|
| Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells | Not triphasic |
| Cytologically bland | Cytologically atypical |
| Rare mitotic figures | Frequent mitotic figures |
| Fibrous Hamartoma of Infancy | Infantile Fibrosarcoma |
|---|---|
| Triphasic lesion with spindle cell fibrous areas, adipose tissue and clusters of immature mesenchymal cells | Not triphasic |
| Rare mitotic figures | Frequent mitotic figures |
| 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 |
| Gardner Associated 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 |
| Age range 2 mo to 36 years | Age range congenital to 4 years |
