“Intraparenchymal leiomyoma of breast with atypical features: diagnostic dilemma”

Abstract Background Breast leiomyoma is a rare neoplasm, accounting for less than 1% of all breast neoplasms. Most of the leiomyomas occur in the subareolar region. There are a few reported cases of intraparenchymal leiomyoma. Rarely reported, cases of intraparenchymal leiomyoma with atypical features are not a well-defined entity, and little is known about their clinical course. Case presentation We present a rare case report of breast parenchymal leiomyoma in a 45-year-old woman. The clinical characteristics, imaging findings, and histology of the lesion are discussed here. Atypical morphological features observed in this case were focal atypia, increased mitosis, and Ki-67 proliferation index. Conclusion In the absence of a well-defined diagnostic criteria, the exact behavior of parenchymal leiomyoma with atypical features is difficult to ascertain. These cases should be closely followed after wide local excision.