Clinical management of myoid hamartomas of the breast: A case report and literature review

Background: Myoid Hamartoma of the breast (MHB) is an extremely rare benign breast lesion composed of mammary ducts and lobules, fibrous stroma, adipose tissue, and smooth muscle. Due to its rarity, the clinical management of MHB is not well described. Surgical excision is the most common form of management. This study reviews the current literature on the clinical management of MHB and describes a case report of a young patient presenting with MHB managed with surveillance and shared-decision making. Materials and methods: A healthy 23-year-old female presented with a one-year history of a palpable left breast mass. Her right breast exam was normal. Ultrasound of the left breast revealed a 2.7 cm × 1.4 cm × 2.4 cm lobulated mass at the one o'clock position. The mass caused slight discomfort to palpation but otherwise had no associated skin changes. Ultrasound-guided biopsy revealed a left breast myoid hamartoma. Management options were presented to the patient, and she elected to observe the mass with surveillance imaging. Results: There have been no reported cases in the literature of malignant transformation of MHB. Rather than rely on reflexive surgical excision of MHB, our review suggests that surveillance and routine imaging may be an appropriate form of clinical management in patients who present with a favorable clinical and histopathological profile which includes: a low MIB-1 proliferative index, low breast cancer risk assessment score, lesion size less than 1.2 cm, and radiological-pathological concordance. Conclusion: Further research is needed to determine the clinical significance and threshold levels of these clinical and histopathological factors in patient care. However, given current trends to minimize over treatment in breast pathology, we pose that observation of MHB can be performed when favorable clinical criteria is met.