Background Non-neoplastic signet-ring cell change in the endometrium appears to be a degenerative phenomenon associated with abnormal bleeding and exogenous hormone use. It more often occurs from the fourth decade onwards. Understanding this change can aid in distinguishing this condition from potential malignant mimicks. Case report We report four cases of endometrial curettings displaying florid non-neoplastic endometrial signet-ring cell change from women in their fourth and fifth decades with menorrhagia and/or post-menopausal bleeding. All women were on exogenous hormone therapy. All biopsies showed inactive endometrium, with prominent stromal pseudo-decidualisation. The decidual cells showed prominent cytoplasmic vacuolation and were negative for mucin (PAS-D, Alcian blue, mucicarmine), pancytokeratins (AE1/AE3) and histiocytic markers (CD68, MAC387). Electron microscopy showed the vacuoles devoid of organelles. Follow-up curettings showed no neoplastic change. Discussion Non-neoplastic signet-ring change should be recognised and reported where present. The change was first described as an idiopathic postmenopausal decidual reaction. It was recognised as a potential mimick of metastatic carcinoma. The incidence of non-neoplastic endometrial signet-ring cell change is not known. Further study is required to understand this change, and may provide insight to an individual’s response to a specific exogenous hormone regime. A panel of histochemical and immunohistochemical methods should be applied to differentiate this change from various signet-ring cell neoplasms. Conclusions Non-neoplastic endometrial signet-ring cell change is a benign condition. It is important to differentiate this change from a primary or secondary signet-ring cell neoplasm.