Synchronous multiple primary malignant neoplasms in breast, kidney, and bilateral thyroid: A case report.

Background: Multiple primary malignant neoplasms (MPMNs) are rare, while synchronous MPMNs (SMPMNs) are even less common. Owing to the progression of medical technology and the extension of life expectancy, its incidence is gradually increasing.

Case Summary: Although reports of breast and thyroid dual cancers are common, cases of an additional diagnosis of kidney primary cancer within the same individual are rare.