Background: Intracystic papillary carcinoma (IPC) is a distinctive variant of a papillary ductal neoplasm confined to a dilated cystic space. This rare mammary tumor typically appears as a discrete solitary mass in the central region of the breast in a postmenopausal woman. This article presents the case of a female patient with a giant IPC. Relevant literature is briefly reviewed. Case: A 65-year-old woman was admitted for the management of a palpable mass of the left breast. On clinical examination, it was noted that the entire left breast was replaced by an extremely large, irregularly shaped, relatively mobile lesion. The mass was almost fixed to surrounding tissues including skin and pectoral muscle. Due to the size of the tumor the patient underwent a left modified radical mastectomy. Results: The final histopathologic diagnosis was defined as an IPC. Concomitant vascular invasion or metastasis to 19 removed lymph nodes were not noted. Conclusions: Because of its relevant growth pattern and indolent clinical behavior, IPC is conventionally regarded as a variant of intraductal papillary carcinoma with an absence of myoepithelial cells. There have been several cases that indicated a slow evolution of the mass, verifying the perception that IPC is associated with a favorable clinical outcome. Differential diagnoses include colloid or medullary carcinoma, invasive ductal carcinoma, hematoma, benign cyst, or adenofibroma. Axillary lymph-node metastases and markers related to invasion have been documented. Due to the rarity of the tumor and variability observed in treatment strategies, only a few surveys have assessed the significance of lymph-node status and the role of adjuvant treatment. (J GYNECOL SURG 2017:1)