Undescended ovary (UO) is an uncommon congenital condition characterized by the presence of the adnexa above the common iliac vessels, with an estimated incidence of 0.3-2%. Because of its rarity, it is usually presented as a case report. A thorough knowledge of the ovarian embryological development is essential for the clinician, who must be warned about the possibility of associated Müllerian and renal malformations. There may be asymptomatic patients, incidentally diagnosed during infertility evaluation, but when symptoms occur, these are unspecific and most often this disorder is misdiagnosed, the accurate diagnosis being established intraoperatory. The malignant potential of an UO is accepted, although no such cases were reported. The role of the UO in infertility is still unclear, despite evidence of its normal function. Complications are linked to the ovary (cyst formation, cyst ruptures or tumors) or to the undescended fallopian tube (ectopic pregnancies). The management should be conservative, but there is no consensus about whether it is necessary to excise the ipsilateral undescended tube. We included a short case presentation of an UO cystadenoma misdiagnosed as a renal cyst, which depicts all diagnostic and management dilemmas and inspired us to write this review. The present literature review includes all the cases reported from the early 20th century to the present, with updated data about epidemiology, pathophysiology, clinical and imaging diagnosis, treatment options and prognosis of this rare condition. This paper aims to establish some directions in the diagnosis and management of similar patients and to remind us that, no matter how advanced the imaging investigation techniques might be, a correct preoperative diagnosis may often be missed.