A 61-year-old female patient presented with a painless lump located in the right breast. In 2015 she was diagnosed with mammary-type myofibroblastoma (MFB) in the right breast and underwent a resection. In 2016 there was a unilateral relapse and the second tumorectomy was performed. The patient underwent core needle biopsy, which indicated a non-epithelial spindle cell lesion with immunohistochemistry results CD34+;S100–; p63–; CKPAN–; ER–. On the MRI there was a lobular tumour (37 x 42 x 57 mm) with 2 satellite lesions. Due to the size of the tumour and previous breast surgeries, a nipple sparing mastectomy with reconstruction was performed. Histopathology confirmed MFB (fig. 1, fig. 2). MFB is a rare benign spindle cell tumour of the breast. Due to its rare incidence, no risk factors or genetic predispositions are identified [1]. As MFB is well encapsulated, the treatment of choice is surgery without further adjuvant therapy. Only one relapse of MFB has been reported in the literature so far [2]. There is little data concerning recurrence of MFB [2], therefore careful observation and documentation of recurrent MFBs could prove beneficial in studying the nature of MFB and treating patients.

Figure 1. Microscopic display of hematoxylin and eosin-stained section of classic myofibroblastoma

Figure 2. Spindle shaped, slender, blend and uniform cells closely packed in short fascicles intermixed with hyalinised, thick collagen bundles

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