•Paraneoplastic Cushing's syndrome is rarely seen in gynecologic cancers, appearing only in case reports•It almost universally results in acute decompensation and portends a poor prognosis•We describe a patient with metastatic endometrial carcinoma with both paraneoplastic Cushing's syndrome and hypercalcemia•High clinical suspicion for malignancy is essential, as these syndromes improve with treatment of the underlying malignancy.
Keywords: ACTH, adrenocorticotrophic hormone; Cushing's syndrome; Endometrial cancer; Hypercalcemia; PNES, paraneoplastic endocrine syndromes; PNS, paraneoplastic syndromes; Paraneoplastic syndrome.