Myofibroblastoma

Myofibroblastoma, also known as myogenic stromal tumor, is a rare benign tumor of the breast characterized histologically by spindle cells (myofibroblasts) in fascicles with varying degrees of myogenic and fibroblastic differentiation. Initially felt to be a tumor predominantly of the male breast, more recent studies have shown that the sex distribution may not be as skewed towards males.

Mammographic findings sometimes suggest a benign diagnosis: A circumscribed lesion without architectural distortion. Coarse calcifications have been reported in association with myofibroblastomas. A case of myofibroblastoma mimicking a hamartoma has been described at our institution, and a case of myofibroblastoma arising in a hamartoma has also been reported in the pathology literature.

However, the tumor may also be mammographically occult or have ill-defined margins.

Ultrasound reveals a circumscribed hypoechoic to mildly hyperechoic lesion with or without distal acoustic attenuation.

References

• Greenberg JS, Kaplan SS, Grady C. Myofibroblastoma of the breast in women: imaging appearances. AJR Am J Roentgenol. 1998 Jul;171(1):71-2.
• Kobayashi N, Oda K, Yokoi S, Kanda H, Hayakawa S, Tang X, Osamura Y. Myofibroblastoma of the breast: report of a case. Surg Today. 1996;26(9):727-9.
• Lee YS, Gilcrease M, Wu Y, Yang WT. Myofibroblastoma of the breast: Imaging features. Eur J Radiol Extra. 2010; 73(1):e13-e15.
• Pina L, Apesteguía L, Cojo R, Cojo F, Arias-Camisón I, Rezola R, De Miguel C. Myofibroblastoma of male breast: report of three cases and review of the literature. Eur Radiol. 1997;7(6):931-4.
• Uchôa DM, Cruz DB, Schaefer PG, Pêgas KL, Cambruzzi E. Myofibroblastoma arising in mammary hamartoma: a case report. Patholog Res Int. 2010 Aug 1;2010: