Angiomyofibroblastoma

Definition

• Circumscribed edematous lesion of the external genitalia and perineal soft tissue

Diagnostic Criteria

• Restricted to external genitalia and perineal soft tissue
  • Rare in males
• Most under 5 cm
• Circumscribed with thin pseudocapsule
• Edematous background with prominent vascularity
  • Thin walled dilated capillaries and venules
  • Scattered bundles of collagen
  • Occasionally sclerotic
  • No necrosis
• Alternating hypercellular and hypocellular areas
  • Cells frequently aggregated around vessels
    • Nests and occasional solid compact foci
    • Also scattered individual cells
    • Hypocellular areas can resemble aggressive angiomyxoma except the vessels are not as thick walled
  • Spindle to round cells
    • May be epithelioid
    • May have plasmacytoid appearance
    • Eosinophilic cytoplasm, occasionally hyaline
    • Bland to minimally atypical oval nuclei
      • Inconspicuous nucleoli
      • Mitotic figures rare, no atypical mitotic figures
    • Binucleate and multinucleate cells common
• Frequently fat in lesion
  • Not clear if this is entrapped or lesional fat
  • May occasionally be prominent ("lipomatous variant")
  • Two reported scrotal lesions were predominantly adipose tissue
• Occasional findings
  • Prominent spindle cell population
  • Stellate cells
  • Degenerative nuclear hyperchromasia
  • Mast cells may be numerous

Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting:: May 27, 2007

Supplemental studies

Immunohistology

Differential Diagnosis

• Aggressive angiomyxoma
• Fibroepithelial stromal polyp
• Cellular angiofibroma
• Superficial myofibroblastoma
• Superficial angiomyxoma
• Glomus tumor
• Epithelioid leiomyoma

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

Clinical

• Age 23-88 years
• Predominantly subcutaneous
• 0.5-14 cm
  • Rarely over 10 cm
• Involves external genitalia and perineal soft tissssue
• Occasionally involves vagina
• Nearly all in females
  • Rarely involves scrotum or inguinal region in males
• Does not recur

Grading / Staging / Report

Grading and staging are not applicable

The surgical pathology report should contain or address the following:

• Location
• Type of resection or biopsy
• Histologic diagnosis
• Managerial category Ia (Local excision is almost always curative; metastasis never occurs)
• Size
• Depth (dermis, subcutis, below fascia, body cavity)
• Results of supplementary studies if performed
• Relationship to other specimens from the same patient

Lists

Vulvovaginal stromal and spindled tumors

• Aggressive angiomyxoma
• Angiomyofibroblastoma
• Cellular angiofibroma
• Fibroepithelial stromal polyp
  • Standard
  • Pseudosarcomatous/cellular
• Nodular fasciitis
• Postoperative spindle cell nodule
• Spindle cell epithelioma (vaginal mixed tumor)
• Superficial angiomyxoma
• Superficial myofibroblastoma

Bibliography

• Kempson RL, Fletcher CDM, Evans HL, Henrickson MR, Sibley RS. Tumors of the Soft Tissues, Atlas of Tumor Pathology, AFIP Third Series, Fascicle 30, 2001
• Fletcher CDM, Unni KK, Mertens F. Pathology and Genetics of Tumours of Soft Tissue and Bone, World Health Organization Classification of Tumours 2002
• Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 4th edition, 2001
• Bigotti G, Coli A, Gasbarri A, Castagnola D, Madonna V, Bartolazzi A. Angiomyofibroblastoma and aggressive angiomyxoma: two benign mesenchymal neoplasms of the female genital tract. An immunohistochemical study. Pathol Res Pract 1999;195(1):39-44.
• Fletcher CD, Tsang WY, Fisher C, Lee KC, Chan JK. Angiomyofibroblastoma of the vulva. A benign neoplasm distinct from aggressive angiomyxoma. Am J Surg Pathol 1992 Apr;16(4):373-82.
• Fukunaga M, Nomura K, Matsumoto K, Doi K, Endo Y, Ushigome S. Vulval angiomyofibroblastoma. Clinicopathologic analysis of six cases. Am J Clin Pathol 1997 Jan;107(1):45-51.
• Granter SR, Nucci MR, Fletcher CD. Aggressive angiomyxoma: reappraisal of its relationship to angiomyofibroblastoma in a series of 16 cases. Histopathology 1997 Jan;30(1):3-10.
• Hisaoka M, Kouho H, Aoki T, Daimaru Y, Hashimoto H. Angiomyofibroblastoma of the vulva: a clinicopathologic study of seven cases. Pathol Int 1995 Jul;45(7):487-92.
• Katenkamp D, Kosmehl H, Mentzel T, Reinke J. [Angiomyofibroblastoma of the vulvar and paravaginal region--a new entity] Pathologe 1993 May;14(3):131-7 [Article in German]
• Laskin WB, Fetsch JF, Mostofi FK. Angiomyofibroblastomalike tumor of the male genital tract: analysis of 11 cases with comparison to female angiomyofibroblastoma and spindle cell lipoma. Am J Surg Pathol 1998 Jan;22(1):6-16.
• Laskin WB, Fetsch JF, Tavassoli FA. Angiomyofibroblastoma of the female genital tract: analysis of 17 cases including a lipomatous variant. Hum Pathol 1997 Sep;28(9):1046-55.
• Nielsen GP, Rosenberg AE, Young RH, Dickersin GR, Clement PB, Scully RE. Angiomyofibroblastoma of the vulva and vagina. Mod Pathol 1996 Mar;9(3):284-91.
• Nielsen GP, Young RH, Dickersin GR, Rosenberg AE. Angiomyofibroblastoma of the vulva with sarcomatous transformation ("angiomyofibrosarcoma"). Am J Surg Pathol 1997 Sep;21(9):1104-8.
• Nucci MR, Granter SR, Fletcher CD. Cellular angiofibroma: a benign neoplasm distinct from angiomyofibroblastoma and spindle cell lipoma. Am J Surg Pathol 1997 Jun;21(6):636-44.
• Ockner DM, Sayadi H, Swanson PE, Ritter JH, Wick MR. Genital angiomyofibroblastoma. Comparison with aggressive angiomyxoma and other myxoid neoplasms of skin and soft tissue. Am J Clin Pathol 1997 Jan;107(1):36-44.
• Silverman JS, Albukerk J, Tamsen A. Comparison of angiomyofibroblastoma and aggressive angiomyxoma in both sexes: four cases composed of bimodal CD34 and factor XIIIa positive dendritic cell subsets. Pathol Res Pract 1997;193(10):673-82.