Probable hamartoma in a Holstein neonate.

Keywords: ovary, bovine, neonate, cyst, mucus

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A female Holstein calf was submitted by RDVM having died approximately one day after it had been born. Signs of acute septicemia at post mortem examination suggested that septicemia as the cause of death. The calf weighed 46 kg

The reproductive tract was particularly interesting: The right ovary had been replaced by a large cyst weighing approximately 287g. This suggested that the cyst contained approximately 280 mL of fluid. This fluid was yellow and transparent, foaming on aspiration suggestion some content of protein. During dissection, the cyst was found to contain two smaller cysts, one of which was lined by hemorrhagic tissue approximately 1 mm thick.

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The entire ovary was retained for histological examination. Histology was examined at the sites marked Cyst 1 and Cyst 2 above. Clicking on the links Cyst 1 and Cyst 3 will open an interactive microscopy system that allows one to examine those samples. This author detected no signs of neoplasia in the wall of the cyst but occasional foci of round cell infiltrations were seen, indicating chronic inflammation due perhaps to tissue necrosis. In the opinion of Dr Donald Schlafer DVM. PhD, ACT, ABVP, this structure is probably a hamartoma, not a granulosa cell tumor. However, a definitive diagnosis was not possible without additional tissue (unavailable). A hamartoma is a focal malformation that resembles a neoplasm. It is however not a tumor, growing at the same rate as the surrounding tissue. It is essentially a disorganized mass of tissue elements normally found in that organ.

On gross examination, the left ovary appeared to be inactive. The ovary and the tip of the uterus adjacent to the ovary was retained for histology. The histology of those samples can be seen by clicking here. The ovary showed frequent nests of the stromal cells that usually surround primary and secondary follicle development. However, using the histology of ovaries of one and three month old calves as reference points, these nest appeared to be more dominant than expected and oocytes were not as frequently seen as expected. In the opinion of Dr Schlafer, this ovary appeared dysplastic, concurring with the author's opinion.

The structure of the caruncles, devoid of glandular development is easy to appreciate. In the cross section of the tip of the horn, the caruncles bulge into the lumen of the uterus. In the inter-caruncular areas, sections of rudimentary glands are visible.

The rest reproductive tract appeared to be normal other than a large accumulation of gelatinous mucus in the vagina cranial to the area of the hymen. There was no persistent hymen i.e. the vaginal lumen was continuous from the vulvar lips to the cervix, yet the mucus was thick enough to be localized to the anterior vagina.

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The caruncles appeared to be particularly well-developed, more so than normal, as did the clitoris. With an absence of follicle activity in the non-cystic ovary (an otherwise potential source of steroids) the collection of mucus in the cranial vagina and development of the caruncles and clitoris suggested that the cyst may have been endocrinologically active. Steroid assay of its fluid content is pending.
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A paraovarian cyst

Keywords: paraovarian, bovine, cow, ovary, cyst, müllerian, wolffian, Kobelts

The structure shown here could either be a wolffian  (Kobelt's or mesonephric) cyst or a remnant of the müllerian system i.e. a paramesonephric cyst. Even in the human literature there is considerable confusion as to the origin of these cysts. Therefore they are often grouped loosely as "paraovarian cysts". Even the histology of the cyst may not reveal its origin, especially in veterinary medicine where these cysts had not been studied as adequately as they have in human medicine.

The cysts have virtually no practical importance because they usually do not impede normal reproductive function. They are occasionally seen on ultrasonography of the ovaries and can be palpated if they are large. 

Paraovarian cysts appear to be more common in horses than in cattle, but in theory, could exist in any species.

The incision across the ovary is incidental; made to demonstrate the presence of the corpus albicans, it's crown just visible at the site of the incision.

Cystic follicle in a cow

Keywords:  anestrus, COD, cyst, cystic, follicle, bovine, management, cow, estrous, cycle

Reproductive tract from a cow with cystic ovarian disease (COD); a syndrome associated with high milk production and negative energy balance in high producing dairy cows. COD is usually associated with persistence of large, un-ovulated follicles in the absence of standing estrus, probably because of luteinization (with progesterone production) of the cystic structures due to low pulsatile releases of LH. Nevertheless, this illustration shows that ovulation occasionally occurs in the presence of a cystic follicle. Note the corpus luteum in the left ovary, in the same ovary as the cyst.

In these cases, the cyst may then regress and may even be replaced by other cysts until ovulation becomes predictable and cyclicty returns to normal.

This illustration also suggests that luteinization of cystic follicles may be so limited that they not produce enough progesterone to suppress LH and block ovulation.

The terminology of COD can be confusing, with cystic follicle occasionally being referred to as luteal cysts. In the author's opinion this term should not be used because it can be confused with a structure called a cystic corpus luteum; a non-pathological entity. Instead, when a cyst becomes luteinized it should be called a luteinized cyst rather than a luteal cyst.