Wide Margins are Still Relevant: A Case of a Well-Circumscribed Borderline Phyllodes Tumor With a Satellite Nodule in a Re-excision Margin.

Phyllodes tumors (PTs) of the breast are rare fibroepithelial neoplasms with high rates of local recurrence (LR) for which surgical excision remains the mainstay of treatment. The recommended surgical margin width is debated and varies based on the histologic grade. We present a case of a middle-aged woman with a well-circumscribed borderline PT who underwent margin re-excision, with a distinct focus of the PT detected at a previously negative margin. Given the high rates of LR and potential for histologic upgrade at the time of recurrence, combined with the current limited understanding of peritumoral tissue and possible satellite foci, a wide negative margin remains the recommendation for borderline PTs.