Background: Phyllodes tumors of the breast, a rare fibroepithelial neoplasm, pose diagnostic and therapeutic challenges due to their diverse morphological spectrum and classification into benign, intermediate, and malignant variants. This abstract explores the clinical manifestations, histological features, and management complexities associated with these tumors, emphasizing the diagnostic difficulties in differentiating them from other fibroepithelial lesions. Case Report: A 35-year-old female with a Malignant Giant Phyllodes tumor, sought medical attention due to a rapidly enlarging lump in her right breast. The tumor measured 20×20×15 cm, emphasizing the diagnostic challenges posed by such substantial masses. Diagnostic procedures included fine-needle aspiration cytology (FNAC) and tru-cut biopsy, revealing the difficulties in achieving diagnostic consistency among pathologists. The patient underwent a right mastectomy, and the post-operative course was uneventful. However, the biopsy report indicated malignant Phyllodes with positive margins. Despite recommendations for revision surgery, the patient declined, highlighting the complexities in patient management. Conclusion: This case contributes valuable insights to the medical literature, emphasizing the intricate diagnostic process and surgical decisions involved in managing Malignant Giant Phyllodes tumors.