This case report details a rare instance of primary squamous cell carcinoma (PSCC) of the breast in an octogenarian, emphasizing the unique diagnostic and treatment challenges posed by this malignancy in an elderly patient and adding to the scientific literature on PSCC managed with breast conservation therapy (BCT). An 80-year-old woman with medical comorbidities presented with a focal asymmetry in the right breast's retroareolar plane, detected during routine screening mammography. Diagnostic evaluations raised high suspicion for malignancy, confirmed as PSCC by ultrasound-guided biopsy. Histopathological analysis showed atypical keratinizing squamous epithelial nests and cysts. The patient underwent lumpectomy and re-excision of close surgical margins with a sentinel lymph node biopsy, which showed well-differentiated invasive squamous cell carcinoma with no residual carcinoma or nodal involvement. She was treated with adjuvant hypofractionated radiation therapy, experiencing minimal side effects. This case highlights the importance of considering individualized, nuanced approaches to adjuvant therapies in the treatment of PSCC in older patients. It demonstrates that BCT, coupled with carefully selected adjuvant therapy, can be a successful treatment strategy for PSCC in the elderly, contributing valuable insights into the management of this rare condition.