Background and Aims Myoid hamartoma of the breast (MHB) is an extremely rare subtype of breast hamartomas, with only case reports documented in the literature. At present, its clinical and pathological features are not well understood, so it is easy to cause missed diagnosis and misdiagnosis. To raise awareness of this disease, herein, the authors report a case of MHB, combined with reviewing 23 cases of MHB reported in the literature, to investigate its histogenesis, clinicopathologic characteristics, and clinical diagnosis and treatment as well as the prognosis.Methods Retrospective clinicopathologic analysis was performed on one case of MHB treated in the authors’ hospital and 23 cases of MHB reported in China.Results All patients were female, and their age at onset ranged from 19 to 65 years, with an average age of (37±12.3) years. All the 24 patients had a solitary lesion, and the maximum diameter of the lesions ranged from 1.9 to 10.0 cm, with an average of (2.9±1.94) cm. The case reported by the authors had the largest tumor volume (10 cm in diameter) among the whole group, which accounted for 0.05% of the total 1 849 breast biopsy specimens and 0.1% of the total breast benign tumors in the authors’ hospital over the past 20 years. Imaging examinations showed that all tumors presented as a well-demarcated lump, but the images were nonspecific; ultrasound-guided core needle biopsy had certain diagnostic value. Naked-eye observation showed that all lesions were well-circumscribed, mobile and painless breast mass or nodule, and were similar to fibroadenoma. Twenty-one patients (87.5%) underwent simple breast lump excision, and 3 patients (12.5%) received extended breast mass excision. Fourteen patients (58.3%) had a clinical diagnosis record, but all were misdiagnosed or considered as breast fibroadenoma. The results of histopathological examination showed that all lesions were composed of randomly mixed mammary ducts, acini and fibroadipose tissue in varying proportions; distinctive well-differentiated smooth muscle tissue or myoid cells were seen in the tumors. Immunophenotypic analysis showed that there were diffuse and strongly positive staining for desmin, α-SMA, vimentin, MSA and h-caldesmon in the smooth muscle component in the tumors. Postoperative follow-up was obtained in 20 patients (83.3%) for an average of (18.6±15.4) months, reoccurrence occurred once in one case 10 months after operation, occurred twice in one case 36 and 41 months after operation, and occurred in none of the remaining cases.Conclusion MHB is a rare benign tumor with high misdiagnosis rate. Clinicians should enhance their understanding and diagnostic awareness of MHB. It should be differentiated from tumors such as breast fibroadenoma and other tumor-like lesions of the breast. MHB may recur, so extensive local resection should be adopted to ensure a negative margin, and regular postoperative follow-up should be performed.