Surgical Pathology Criteria

Superficial Myofibroblastoma

Differential Diagnosis

The first six entities are predominantly perineal in location and may be confused with superficial myofibroblastoma

Superficial Myofibroblastoma Angiomyofibroblastoma
Inconspicuous vascularity Prominent vascularity
Stellate and spindled cells Perivascular epithelioid cells


Fibroepithelial Stromal Polyp Superficial Myofibroblastoma
Wide age range Most 40-70's
Superficial lesional cells, hypocellular core Lesional cells throughout
No grenz zone Usually grenz zone
May have bizzare stromal cells No bizzare stromal cells
No architectural pattern Frequent lace-like pattern


Cellular Fibroepithelial Stromal Polyp Superficial Myofibroblastoma
Young, frequently pregnant Most 40-70's
Cellularity predominanlty superficial Cellularity varies throughout
No grenz zone Usually grenz zone
Scattered bizarre or multinucleated cells Uniform bland cells
Mitotic figures may be frequent Mitotic figures <1/10 hpf


Superficial Myofibroblastoma Cellular Angiofibroma
Desmin positive Desmin 10% positive
Inconspicuous thin walled vessels Prominent thick walled vessels
No fat Frequently contains fat
ER and PR >90% ER and PR 35-55%
Both are superficial and may be CD34 postive. Cellular angofibroma may occur in males.


Superficial Myofibroblastoma Aggressive Angiomyxoma
Age 40-70's Young patients
Small, superficial Large, deep
Circumscribed Frequently infiltrative
Inconspicuous vessels Prominent thick walled hyalinized vessels
Both are frequently positive for desmin, CD34, ER, PR


Vaginal Spindle Cell Epithelioma Superficial Myofibroblastoma
Squamous or glandular component No epithelial component
Keratin postive Keratin negative
Desmin negative Desmin positive


Superficial myofibroblastoma is restricted to perineal and genital regions, while the entities considered below may occur in a wide variety of sites.


Superficial Angiomyxoma Superficial Myofibroblastoma
Mean age 20 years for perineal lesions Most 40-70's
Long thin walled vessels Inconspicuous vessels
Desmin, ER, PR negative Desmin, ER, PR positive
S100 variable S100 negative
Stromal neutrophils No stromal neutrophils
Frequently multinodular Single nodule
Frequently involves subcutis Superficial
Paucicellular Cellular areas


Nerve Sheath Tumor Superficial Myofibroblastoma
S100 positive S100 negative
Desmin negative Desmin positive
Both may be CD34 positive


Solitary Fibrous Tumor Superficial Myofibroblastoma
Frequent stag horn vessels Inconspicuous vessels
Desmin negative Desmin positive
CD34 positive CD34 variable

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