A rare case report of solitary neurofibroma arising in the male breast.

Introduction and Importance: Primary tumors of the chest wall are fairly uncommon and typically involve the mammary glands. Additional breast lesions usually involve the soft tissues, with neurofibromas comprising a significantly low amount of cases that skew toward female patients. A neurofibroma of the male breast is an exceedingly rare occurrence; however, most cases are associated with Neurofibromatosis Type 1 (NF1). This report aims to present the case of a solitary neurofibroma in the breast of a male patient in the absence of a diagnosis of Neurofibromatosis, a situation with only three prior cases documented in the literature. In addition, we review the literature and management approach for this rare occurrence. Presentation of Case: A 41-year-old male with a PMHx of medication-controlled HTN and migraines noticed a small firm mass in his left breast years ago that recently started causing discomfort with deep palpation despite no reported significant changes in size or development of additional symptoms. Preliminary diagnostic studies (diagnostic mammogram, targeted ultrasound, ultrasound-guided biopsy) illustrated a circumscribed, spiculated oval mass 3 cm from the nipple-areolar complex at the 9-o'clock position, with a biopsy report indicative of a neurofibroma. The patient underwent elective surgical excision of the lesion, and the surgical pathology report additionally confirmed the diagnosis of a neurofibroma. Clinical Discussion: Neurofibromas are benign peripheral nerve sheath tumors that originate from the endoneurium, the connective tissue of nerve sheaths. Solitary neurofibroma of the male breast in the absence of a diagnosis of neurofibromatosis is a substantially rare occurrence, with only three prior confirmed cases documented. Current literature suggests surgical excision as the mainstay of management, regardless of their low risk of malignant transformation. Conclusion: To our knowledge, this is only the fourth case of its kind and the only one to provide gross imagery and two separate confirmatory pathology reports. Implications of the findings include continued preferred management via surgical excision, remaining awareness of rare tumors, and additional evidence for the possible prevalence of rare male breast tumors that may have been previously not considered.