Discussion

Diagnosis  

Cellular Angiofibroma (Angiomyofibroblastoma-like tumor)

Discussion 

Myofibroblastic tumors are a subset of mesenchymal neoplasms arising in the soft tissues. Within this group are two histomorphologically similar lesions, angiomyofibroblastoma (AMF) and cellular angiofibroma/angiomyofibroblastoma-like (AMF-like) tumor. These are small, painless, slowly-enlarging lesions, often present in the female vulvar or male inguinoscrotal region. They are treated via wide-local excision with an extremely low likelihood of recurrence.

In 1992, Fletcher et al. characterized AMF as a benign stromal tumor found in the female vulva and rarely in the male inguinoscrotal region. This tumor is well-circumscribed and consists of hypercellular areas of spindled stromal cells and edematous hypocellular areas with loose collagen. Small-to-medium sized vessels are haphazardly distributed throughout the stroma and the spindled cells often arrange themselves around these vessels. Mitotic figures and necrosis are rarely identified.

In 1997, Nucci et al. first described cellular angiofibromas as superficial soft tissue tumors located in the vulva of middle-aged women consisting of spindled cells and thick-walled vessels. Further studies by Iwasawa and Fletcher showed that these lesions are evenly distributed between the vulvar region in females and the inguinoscrotal region in men. The spindled cells are bland and arranged haphazardly, or in short fascicles, in a stroma consisting of wispy to thick collagen fibers.

Additionally, there are small-to-medium sized hyalinized vessels and intralesional fat may be present. Immunohistochemically, 60% of cellular fibromas are positive for CD34, there is variable SMA and desmin staining, and S100 is negative. Many cases also stain positive for ER and PR; however this is more common in females. Lastly, when considering a diagnosis of cellular angiofibroma, the histologic differential includes spindle cell lipoma, mammary-type myofibroblastoma, solitary fibrous tumor, and aggressive angiomyxoma. 

References

​Canales, B.K., et al., Angiomyofibroblastoma-like tumors (cellular angiofibroma). Int J Urol, 2006. 13(2): p. 177-9.

Ding, G., et al., Angiomyofibroblastoma-like tumor of the scrotum: A case report and literature review. Oncol Lett, 2014. 7(2): p. 435-438.

Fletcher, C.D., et al., Angiomyofibroblastoma of the vulva. A benign neoplasm distinct from aggressive angiomyxoma. Am J Surg Pathol, 1992. 16(4): p. 373-82.

Fletcher, C.D.M., U. Flucke, and Y. Iwasa, Cellular Angiofibroma, in WHO Classification of Tumours of Soft Tissue and Bone, C.D.M. Fletcher, et al., Editors. 2013, IARC: Lyon. p. 65-66.

Goldblum, J.R., A.L. Folpe, and S.W. Weiss, Cellular Angiofibroma, in Soft Tissue Tumors, E. Weiss, Editor. 2014, Elsevier Saunders: Philadelphia, PA. p. 539-540.

Flucke, U., J.H.J.M. van Krieken, and T. Mentzel, Cellular angiofibroma: analysis of 25 cases emphasizing its relationship to spindle cell lipoma and mammary-type myofibroblastoma. Modern Pathology, 2010. 24: p. 82.

Iwasa, Y. and C.D. Fletcher, Cellular angiofibroma: clinicopathologic and immunohistochemical analysis of 51 cases. Am J Surg Pathol, 2004. 28(11): p. 1426-35.

Laskin, W.B., J.F. Fetsch, and F.K. Mostofi, 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. 22(1): p. 6-16.

Lee, S.H., et al., Angiomyofibroblastoma-like tumor of the scrotum. Korean J Urol, 2010. 51(5): p. 365-7.

Maruyama, M., et al., Magnetic resonance imaging features of angiomyofibroblastoma-like tumor of the scrotum with pathologic correlates. Clin Imaging, 2012. 36(5): p. 632-5.

Msakni, I., et al., Paratesticular Angiomyofibroblastoma-Like Tumor: Unusual Case of a Solidocystic Form. Case Rep Med, 2017. 2017: p. 1273531.

Nucci, M.R., S.R. Granter, and C.D. Fletcher, Cellular angiofibroma: a benign neoplasm distinct from angiomyofibroblastoma and spindle cell lipoma. Am J Surg Pathol, 1997. 21(6): p. 636-44.

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