Mammary myofibroblastoma: a case report

Background: Myofibroblastoma is a benign mesenchymal tumour which can be challenging to diagnose. It has range of histological features that overlap with other or malignant neoplasms.1 Adjunct testing demonstrates RB1 loss on immunohistochemistry and monoallelic 13q14 region FISH seal the diagnosis this lesion curative local excision.2,3 Case summary: We report case 45-year-old female who presented right breast nodule. A core biopsy showed stromal spindle cell proliferation working included myoid hamartoma, fibroepithelial carcinoma. The excision revealed vaguely circumscribed cells arranged in fascicles interspersed by hyalinised collagen bundles. were positive for SMA, Desmin ER but negative CKAE1/3, B-catenin, S100, CK broad spectrum p63. also RB1. analysis at 35.5% nuclei confirming myofibroblastoma. Conclusion: constellation when supported confirms entity preventing unnecessary further management. References 1. Shanmugasiva VV, Ramli Hamid MT, Fadzli F, Shaleen Kaur KS, Abd Rahman N, Rahmat K. breast. Malays J Pathol 2018; 40: 349–353. 2. Wickre M, Valencia E, Solanki Glazebrook Mammary extramammary myofibroblastoma: multimodality imaging clinicopathologic correlation, management, outcomes series 23 patients. Br Radiol 2021; 94: 20201019. 3. D'Alfonso TM, Subramaniyam S, Ginter PS, et al. Characterization leiomyomatous variant rare subset distinct from smooth muscle tumors Hum 2016; 58: 54–61.