We are aware of at least 50 published reports of additional ovarian tissue since Wharton published his seminal description in 1959 [1
]. He defined an accessory
ovary as having close proximity and some form of association to a eutopic ovary and its associated blood supply. The term supernumerary
ovary was reserved for ovarian tissue far removed from the eutopic ovaries and with a separate blood supply. The former is often found attached to the fallopian tube or one of the various ligamentous structures of the ovarian-uterine complex; the latter can be found anywhere along the embryological migratory path of the ovarian primordium, including the mesentery, retroperitoneal space, and omentum [2
The terminology employed has caused substantial confusion on the subject. The terms supernumerary
are somewhat misleading because their definitions by Wharton presuppose two normal ovaries and an embryologic origin for the additional ovarian tissue. It has been suggested that up to 50% of cases of additional ovaries are actually post-inflammatory or post-surgical implants [3
]. Lachman et al have suggested doing away with the traditional terms and labeling all abnormally placed ovarian tissue as ectopic
, subcategorized as either post-surgical, post-inflammatory, or truly embryological [3
]. Unfortunately, this schema fails to make a distinction between 1) extra tissue that is present in addition
to two eutopic ovaries and 2) that which exists in place of
a eutopic ovary because it is the result of defective migration or development of an ovarian primordium [5
]. Therefore, it is difficult to precisely determine the incidence and categorize the characteristics of the phenomenon.
About 36% of reported cases of ectopic ovary are associated with urogenital anomalies [6
]. Their incidence in patients with absent uterus is as high as 20%, and in as many as 42% of cases of unicornuate uterus there is associated ectopia, and often malformation, of the ovary contralateral to the developed cornu [7
]. The majority of cases are classified as supernumerary
by the Wharton criteria. The detection of both supernumerary and accessory ovaries is often associated with tumors or cysts, perhaps precisely because these are symptomatic and require subsequent workup. Some authors support the idea that this association is due to increased pathological potential of the ectopic tissue [6
The most common masses identified are mature teratomas and mucinous cystadenomas, present in up to one fifth of patients [5
]. In addition, Brenner's tumor [8
], sclerosing stromal tumor [9
], serous cystadenoma [10
], serous cystadenofibroma [11
], fibroma [12
], and adenocarcinoma have been described. Common clinical presentations involve abdominal pain and irregular menses.
Despite the strong association with pathological processes, supernumerary and accessory ovarian tissue has been notoriously difficult to diagnose preoperatively. It is usually an incidental finding or a surprise histopathological diagnosis after resection of a clinically relevant mass, as occurred in this case. It can be suspected on the basis of hormonal abnormalities, such as continued cyclic endometriosis pain [4
] or intact estrogenic response to human chorionic gonadotropin [13
] after bilateral oopherectomy. Fujiwara et al. have even made a presumptive diagnosis based on cyclic, FSH-associated changes in a cystic mass, visualized by ultrasound [14
]. Normally, however, the nature of the mass is uncertain until histological confirmation is obtained.
The patient's young age and impressive weight are unusual features of this case. To our knowledge, there have only been five previously reported cases of additional ovaries diagnosed in children under the age of eighteen. This includes the two neonatal diagnoses reported by Kuga et al [2
]. If the child's obesity is related somehow to a rapid progression of the tumor that led to the relatively early detection, the mechanism is uncertain: although various hormone and gonadotropin receptors have been detected to varying degrees on samples from the spectrum of serous ovarian neoplasms, they have not been shown definitively to promote tumor growth [15
]. Unfortunately, we do not have comprehensive hormone levels for our patient, although one would expect her estrogen levels to be increased (due to obesity) and her FSH levels to be chronically decreased (due to pituitary axis inhibition); her ovaries were not polycystic and she was not hirsute, suggesting normal LH and androgen levels.
To improve the precision of the terminology, we would propose that the term ectopic continue to refer to any inappropriately placed ovarian tissue, regardless of etiology or the presence of two eutopic ovaries. The description can be fine-tuned according to the salient features of the specific presentation and its suspected etiology, e.g. "extra/additional" if accompanied by normal ovaries, or "malformed" if the product of faulty migration or malformation of a would-be eutopic gonad. One can invoke the term "implant" when that etiology is suspected, and Lachman's proposed adjectives "post-surgical" and "post-inflammatory" applied. All permutations of etiology and location can thus be accurately and completely described (e.g., "ectopic extra ovary," "post-inflammatory ectopic implant," or "unilateral ectopic ovarian malformation/remnant"), not previously possible. The terms supernumerary and accessory should retain their traditional Whartonian definitions in that they refer to distinct presentations of additional (extra) ovarian tissue.