Surgical Pathology Criteria

Aggressive Angiomyxoma

Differential Diagnosis

The first four entities are predominantly perineal in location and may be confused with aggressive angiomyxoma

Angiomyofibroblastoma Aggressive Angiomyxoma
Most <5 cm Nearly always >5 cm
Well circumscribed Not circumscribed
Alternating hypercellular and hypocellular areas Hypocellular
Clusters of rounded, epithelioid, frequently plasmacytoid cells Sparse spindled or stellate cells
Numerous small vessels Large thick walled vessels
Actin frequently positive Actin infrequently positive
  • Cases with features of both occur raising the possibility that they form a spectrum.
  • Size may be a critical distinguishing feature.
  • Immunohistochemistry reports of actin staining are variable and thus it may not be reliable for separation; both are desmin positive.
  • Aggressive Angiomyxoma Cellular Angiofibroma
    Usually large, deep lesion Subcutaneous, mean size 6 cm
    Hypocellular Moderately cellular
    Infiltrative margin Circumscribed
    Usually desmin positive Desmin 10% positive
    May infiltrate fat May have fat integral to lesion
    Both have prominent medium sized vessels, both may be CD34+.

    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

    Fibroepithelial stromal polyp Aggressive Angiomyxoma
    Exophytic Sessile, deep lesion
    Often extends to overlying epithelium Practically never extends to overlying epithelium
    Vaginal or cervical Usually in soft tissue
    Usually <5 cm Nearly always >5 cm
    May have scattered atypical stromal cells No atypical cells
    Both contain desmin positive cells

    Superficial Angiomyxoma Aggressive Angiomyxoma
    Usually <5 cm Nearly always >5 cm
    Superficial Deep seated
    Long thin walled vessels Medium to large thick walled vessels
    Desmin negative Desmin positive
    Stromal neutrophils No stromal neutrophils

     

    Aggressive angiomyxoma is virtually restricted to perineal, genital, inguinal regions, while the myxoid entities considered below may occur in a wide variety of sites.

    Intramuscular Myxoma Aggressive Angiomyxoma
    Frequently on extremities Perineal or pelvic
    Hypovascular Prominent medium to large vessels

    Myxoid neurofibroma Aggressive angiomyxoma
    S100 positive S100 negative
    Desmin negative Desmin positive

    Myxofibrosarcoma Aggressive angiomyxoma
    Large cytologically atypical cells Small bland cells
    May have frequent mitotic figures Rare mitotic figures

    Myxoid Liposarcoma Aggressive Angiomyxoma
    Arborizing vessels Large, disorganized vessels
    Signet ring lipoblasts Lacks lipoblasts

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