Introduction: Mammary Paget disease (MPD) usually presents as a neoplasm confined to the epithelium with underlying in situ or infiltrating breast carcinoma. Invasive Mammary Paget Disease with no underlying breast carcinoma (InvMPD) is a rare subtype of MPD that manifests as dermatosis on the nipple's skin. We present a case clinical, radiological, and histopathological characteristics of an InvMPD in a female patient.Case presentation: A 42-year-old woman with a family history of breast cancer consulted with an erythematous lesion on the nipple's skin. Imaging studies revealed a circumscribed lesion consistent with fibroadenoma, which was confirmed by histology. Incisional biopsy and nipple excision revealed an InvPMD. Discussion: MPD is a rare neoplasm that represents 1-3% of all primary breast malignancies. Less frequently, MPD can rarely develop dermal infiltration without underlying carcinoma (invMPD). Five cases of InvMPD have been reported in the literature; therefore, we report the sixth case of InvMPD in a 42-year-old woman. Conclusion:InvMPD is a rare clinical entity that should be considered in cases with no carcinoma in situ or invasive in breast tissue after an extensive radiological and histologically sampling of the nipple is performed.