Unusual ovarian activity in a mare preceding the development of an ovarian granulosa cell tumour

An 8-year-old mare, with a foal at foot, was inseminated on foal heat with frozen semen, with the resultant pregnancy lost between days 34 and 41. The right ovary developed a large anovulatory follicle that was non-responsive to multiple doses of ovulating agents. The follicle eventually appeared to luteinise, although plasma progesterone concentrations did not reflect this. Another follicle developed, responded to GnRH and resulted in a pregnancy from frozen semen that went to term with a healthy foal. When the mare was examined after foaling, the structure on the right ovary appeared to be a granulosa cell tumour; the left ovary was smaller than normal and non-functional. Surgical removal of the right ovary before increasing photoperiod resulted in a return to function of the left ovary and a pregnancy to frozen semen on the second cycle following removal. Figures showing concentrations of inhibin, progesterone, androstenedione, oestradiol and testosterone are presented for this entire period. Unusual ovarian activity in the mare might be a prelude to the development of a granulosa cell tumour.     

Udder development, lactation and ascites in a ewe with an ovarian granulosa cell tumour

A 20-month-old sexually intact female mixed breed sheep was examined for lameness, unexpected udder development, lactation and anorexia. Tachycardia, tachypnoea, severe abdominal distension and vaginal prolapse were evident upon physical examination. A right hindlimb lameness was present at the walk. The udder was well-developed and milk, normal in appearance, was easily expressed from each teat. Ultrasonographic evaluation revealed a non-pregnant uterus, severe ascites and a large (12 cm diameter) abdominal mass. Although surgical treatment was discussed, the owners elected to euthanase the ewe. Necropsy examination confirmed the presence of severe ascites due to a ruptured ovarian tumour. The tumour was characterised as a granulosa cell tumour histologically. Unexpected udder development and lactation presumably occurred secondary to oestrogen and progesterone production by the tumour. To the authors' knowledge, this is the first report of udder development, lactation and ascites in a ewe secondary to an ovarian granulosa cell tumour.     

Metastatic granulosa cell tumor in a mare.

A 5-year-old Quarter Horse mare was referred for evaluation of an acute non-weightbearing lameness of the left hind limb in which musculoskeletal abnormalities had not been detected. After admission, the mare had signs of colic. Exploratory laparotomy revealed the left ovary to be large, masses in the left sublumbar space, and diffuse infiltration of the mesentery, omentum, liver, and spleen with variably-sized masses. The mare was euthanatized, and granulosa cell tumor was identified on histologic examination of the left ovary, left sublumbar and cranial thoracic lymph nodes, omentum, mesentery, liver, spleen, and lung.     

Double ovarian tumour in the mare: Case report

Ovarian tumours in mares represent 2.5% to 6% of the most frequent neoplasms found in the equine species, with a higher chance of benignity. This study aims to describe a case of two different tumours found in the same ovary of a mare that presented clinical signs of suppressed oestrous cycle during 5 years. After unilateral ovariectomy, the ovary was sent to the histopathology examination which determined a mixed tumour of granulosa cell and leiomyosarcoma. After treatment, the mare returned to oestrus and got pregnant in the next season.     

Mast cell tumour in the third eyelid of a mare

A 4‐year‐old Missouri Fox Trotter mare was referred to the Veterinary Teaching Hospital, Koret School of Veterinary Medicine with a reddish mass protruding from the third eyelid and adjacent palpebral conjunctiva of the left eye. On ophthalmic examination, the mare showed mild blepharospasm, mild mucopurulent discharge and mild corneal oedema in the left eye. Menace response, pupillary light reflexes and intraocular examination were normal. A rounded, fleshy red ulcerated mass, approximately 3 cm in diameter, expanded the edge of the outer surface of the medial third eyelid and conjunctiva of the ventromedial palpebral region. Physical examination was otherwise unremarkable. Based on history and clinical findings, surgical removal was elected. The tumour was excised and the conjunctiva in the area of tumour treated with cryotherapy. Histological evaluation revealed a mast cell tumour on the third eyelid. Nine months follow‐up revealed no recurrence.     

Small-colon rupture attributable to granulosa cell tumor in a mare

A large granulosa cell tumor was believed to be responsible for causing obstruction and subsequent rupture of the small colon in a 10-year-old Quarter Horse mare. Two months earlier, a mass, tentatively diagnosed as granulosa cell tumor of the left ovary, had been identified by means of rectal palpation and ultrasonography. The mare was evaluated for clinical signs of acute, severe, abdominal pain, increased heart rate, cyanotic mucous membranes, clinical dehydration, with high PCV, leukopenia, and extreme abdominal distension. A large soft tissue mass and taut band that constricted the lumen of the small colon were palpable per rectum. Septic peritonitis was diagnosed on the basis of results of abdominocentesis. Exploratory surgery revealed extensive fecal contamination of the abdominal viscera, and the mare was euthanatized because of the resultant poor prognosis. At necropsy, the small colon was occluded by a taut, left broad ligament and the ovarian mass that was proved to be a granulosa cell tumor. The occlusion had caused impaction of the small colon, with subsequent perforation at the level of the broad ligament.     

Acute pancreatitis following granulosa cell tumor removal in a mare

Acute pancreatitis is a rare disease in horses and is often associated with gastrointestinal disorders. Accurate diagnosis is challenging due to the presence of nonspecific clinical signs. This case represents the first documentation of acute pancreatitis in a horse following surgery of the reproductive tract.     

Changes of serum anti‐Müllerian hormone in a mare with granulosa cell tumour following surgery and reinitiation of follicular activity

Anti‐Müllerian hormone (AMH) has been reported to be elevated in mares with granulosa cell tumour (GCT). An 8‐year‐old Thoroughbred mare was presented for not being observed in oestrus after the beginning of the breeding season. Rectal palpation and ultrasonography revealed enlargement and cystic appearance of the left ovary while the right ovary was small with an anoestrous‐like appearance. The AMH concentration was 694.9 ng/ml. Presumptively diagnosed with GCT, the mare was subjected to tumour removal. Histopathology confirmed GCT. To evaluate changes of AMH concentration following surgery, blood samples were collected immediately prior to surgery, and on Days 1, 2, 4, 8, 16 and 32 after surgery. Thereafter, blood samples were collected monthly and also at the time the mare was observed in oestrus (148 days after tumour removal). The AMH concentrations decreased over the first 2 months after surgery (from 721.2 ng/ml to 0.1 ng/ml). Subsequently, AMH concentration increased and peaked at the time of oestrus expression (0.7 ng/ml). The mare then became anoestrous, and AMH concentration decreased and reached 0.2 ng/ml, which was not significantly different from the mean concentration of AMH in normal anoestrous mares (n = 5; 0.26 ± 0.07 ng/ml). In conclusion, the present report implies the potential use of AMH for determination of the time of follicular resumption in mares after GCT removal.     

Diabetes mellitus associated with bilateral granulosa cell tumors in a mare

Both ovaries in a 10-year-old American Saddle Horse mare were determined to be larger than normal. The mare had problems with infertility during the preceding 3 years. Clinical evaluation revealed that the mare was polyuric, polydypsic, hyperinsulinemic, and hyperglycemic, and had reduced tolerance to exogenous glucose. Bilateral granulosa cell tumors were identified on histologic examination of the ovaries. The precise mechanism for the secondary diabetes mellitus was not determined; however, the cause was suspected to be a result of the synthesis and release of a hormonal substance by the tumor that affected carbohydrate metabolism and resulted in decreased peripheral sensitivity to insulin.     

Granulosa thecal cell tumour in a mare causing hypertrophic osteopathy

Hypertrophic osteopathy (HO) is a rare condition in the horse characterised by symmetrical proliferation of connective tissue and subperiosteal bone, along the diaphyses of limb bones. In this case, a 10‐year‐old Irish Draught cross Thoroughbred mare was presented for investigation of weight loss, lethargy and firm swelling of all 4 distal limbs. Radiographs of the distal limbs revealed palisade‐like periosteal new bone formation perpendicular to the cortex of the distal third metacarpal and metatarsal bones, proximal (P1) and mid (P2) phalanges. Rectal examination revealed a mass of approximately 20 x 30 cm in the right caudoventral abdomen. The mare was diagnosed with HO due to a granulosa thecal cell (GTC) tumour. The GTC tumour was removed and the diagnosis confirmed on histological examination. Clinical examination and radiographs of the distal limbs after surgery demonstrated reduction in size of the limb swellings and new bone formation. To the authors' knowledge this is the first report of HO due to a GTC tumour in a mare.     

Haemoperitoneum in a pregnant mare with an ovarian haematoma

Haemoperitoneum is a rarely reported but life‐threatening complication of a multitude of disease processes that can affect horses. This report describes an unusual case of haemoperitoneum in a pregnant mare attributed to a unilateral ovarian haematoma during early gestation. The mare was treated with supportive care and discharged 8 days after initial presentation. Following discharge, the mare maintained her pregnancy to term and delivered a live colt at 321 days of gestation.     

Mammary adenocarcinoma and granulosa cell tumour in an aged Toggenberg goat

An adenocarcinoma of the mammary gland was diagnosed in an aged goat with suspected chronic mastitis. On cross-sectioning, the tumour had a lobulated appearance and contained areas of calcification. Histologically, it was multicentric, exhibiting various growth patterns, including “comedo”, papillary and solid. There was no evidence of metastasis to the regional lymph nodes. A well-differentiated granulosa cell tumour of the right ovary was also present.     

Mammary adenocarcinoma and granulosa cell tumour in an aged Toggenberg goat

An adenocarcinoma of the mammary gland was diagnosed in an aged goat with suspected chronic mastitis. On cross-sectioning, the tumour had a lobulated appearance and contained areas of calcification. Histologically, it was multicentric, exhibiting various growth patterns, including comedo, papillary and solid. There was no evidence of metastasis to the regional lymph nodes. A well-differentiated granulosa cell tumour of the right ovary was also present.     

Granulosa cell tumour: An interesting case in a pregnant mare

This report describes the successful management of a pregnant 14‐year‐old seven‐eighths Thoroughbred mare with an ovarian granulosa cell tumour. The mare initially presented with unilateral ovarian enlargement whilst being managed for artificial insemination, demonstrating normal ovarian function with ovulation from the contralateral ovary leading to conception. The mare subsequently re‐presented with stallion‐like behaviour at 3.5 months gestation and ovarian suppression was evident. The mare maintained her pregnancy and delivered a live colt foal at term. Ovariectomy was performed 3 months post foaling and the mare regained cyclic activity 9 months post surgery. The mare then conceived and became pregnant once more. The diagnostic and therapeutic challenges during pregnancy are discussed.     

Granulosa-theca cell tumor associated with an ovulation fossa and normal ovarian stroma in a mare.

A granulosa-theca cell tumor was found in an ovary that had an ovulation fossa and normal ovarian tissue. The ovary was removed from a mare with a history of ovarian enlargement and behavioral changes. The affected ovary had a multicystic appearance on ultrasonographic examination performed before surgery, and an ovulation fossa was not palpable on examination per rectum. However, during surgery, the affected ovary was found to be within normal size limits, with an enlargement on 1 pole, and to contain an ovulation fossa. Atrophy of the infundibulum of the affected ovary helped to confirm the diagnosis of granulosa-theca cell tumor, and the ovary was removed. The mare's testosterone concentrations were normal. Granulosa-theca cell tumors are usually associated with a spherical ovary, attributable to ablation of the ovulation fossa, with no normal ovarian tissue present.