Equine histoplasmosis presenting as a tumor in the abdominal cavity.

A 3.5-year-old Thoroughbred mare presented at necropsy with a large mass at the root of the mesentery and multiple smaller mesenteric masses. The mucosa of the small intestine contained numerous raised nodules. Histologic examination revealed severe granulomatous mesenteric lymphadenitis and enteritis. Epithelioid macrophages and multinucleated giant cells frequently contained numerous intracytoplasmic yeast organisms, which were strongly positive on immunohistochemical staining when using a polyclonal antibody against Histoplasma spp. A diagnosis of abdominal histoplasmosis was made based on the gross, microscopic, and immunohistochemical findings.     

Vaginal evisceration of the small intestine in three mares

Three mares were treated for vaginal evisceration of a portion of the small intestine. Evisceration occurred in 2 mares shortly after breeding accidents in which the stallion's penis penetrated the vaginal fornix dorsal to the cervix. The affected bowel was replaced through the laceration, and the vaginal defects were sutured with the mares standing, utilizing epidural anesthesia. One mare recovered without complications, was subsequently bred, and delivered a foal with no difficulty. The other mare developed signs of a strangulating small intestinal obstruction 24 hours after the injury, necessitating exploratory celiotomy. Two meters of small intestine had become devitalized secondary to avulsion of the mesentery and adjacent vascular supply during the evisceration. The affected portion was resected and a jejunocecostomy was performed. Recovery was uncomplicated and 21 months later the mare was 9 months in foal. A third mare was treated unsuccessfully for evisceration of several meters of small intestine through the external urethral orifice after rupture of the urinary bladder.     

Chronic intestinal pseudo-obstruction in a horse: a case of myenteric ganglionitis

An 11-year-old Quarter horse mare was presented for recurrent episodes of colic. A chronic intestinal pseudo-obstruction was diagnosed. Medical treatment and surgical resection of the colon were performed but the condition did not improve and the horse was euthanized. Histopathological examination revealed a myenteric ganglionitis of the small intestine and ascending colon.     

A Case of Marie's Disease in a Broodmare

An 8-year-old Thoroughbred mare presented with acute bilateral epistaxis. The mare showed no clinical signs other than cough and profuse bilateral epistaxis. Antibiotic therapy was instituted and a transtracheal wash was collected. Large numbers of inflammatory neutrophils and gram-positive cocci were reported in the tracheal wash. The antibiotic therapy was continued for 7 days at which time the mare appeared clinically normal. The mare was successfully bred and was confirmed pregnant. She was referred to a hospital when the epistaxis recurred. She was treated with another antibiotic, and thoracic radiographs were also taken which revealed a space occupying lesion. The mare foaled a live foal. She developed bilateral thickening of her limbs. The swellings were of boney consistency and affected all four legs, particularly the forelimbs. A diagnosis of pulmonary hypertrophic osteopathy was made. The mare was again sent for further investigation. The thoracic mass had increased in size from the first examination. A biopsy was collected by endoscopy which confirmed a neoplastic process. After deterioration in her condition, the mare was euthanized on humane grounds. An autopsy report revealed that the mare had approximately 80% of the left lung replaced by neoplastic tissue. The right lung contained many small nodular masses. There was an associated cardiomegaly. In this case, the development of periosteal proliferation in multiple metaphyses was secondary to an intrathoracic neoplastic mass.     

Segmental ischaemic necrosis of the jejunum in a post-partum mare due to two mesenteric avulsions

This report describes segmental ischaemic necrosis of the small intestine 4 days after foaling in a 9-year-old Arabian mare. The jejunal mesentery was avulsed from the intestine in two locations for 20 and 200 cm, resulting in intestinal necrosis, in the absence of entrapment or strangulation. This case highlights the need to consider the possibility of mesenteric injury when a post-partum mare presents mild signs of abdominal pain.     

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.     

Intestinal carcinoid in a mare: an etiologic consideration for chronic colic in horses

Intestinal carcinoid, or argentaffinoma, should be an etiologic consideration for horses with chronic colic. A mare was referred with a history of chronic colic. Previously, the signs of colic had subsided in response to impiric treatment, but recent episodes of colic did not. Clinical signs and results of physical examination supported the finding of strangulating obstruction of the small intestine. Exploratory celiotomy revealed internal herniation with simultaneous volvulus of the jejunum and accompanying carcinoid.     

Omental fibrosarcoma in a horse

A 13-year-old Thoroughbred mare had a 2-week history of weight loss and intermittent fever. Examination of abdominal and pleural fluid revealed peritonitis and pleuritis. Ultrasonography of the ventral abdominal midline revealed an intra-abdominal mass. Exploratory celiotomy was performed, but the mass was not surgically excisable. The mare was euthanatized and necropsied. Histologically, the mass was determined to be a fibrosarcoma of omental origin.     

Chronic sialolithiasis in a Trakehner mare

An 11-year-old Trakehner mare was presented with a firm moveable mass over the left maxilla. Radiography revealed a discrete opaque ovoid mass. Sialolithiasis of left parotid duct was diagnosed. The sialolith was excised by using a transoral approach and found to contain an organic nidus. The mare recovered without complications.     

GRANULOMATOUS ENTERITIS IN A YOUNG STANDARDBRED MARE

Granulomatous enteritis was diagnosed in a 4-year-old Standardbred mare suffering from chronic weight loss, depression, dependent oedema but not diarrhoea. There was hypoproteinaemia (hypoalbuminaemia), lymphocytopaenia and negligible carbohydrate absorption from the small intestine. Pathological changes in almost the entire small intestine included proprial infiltration resulting in partial villous atrophy, and granuloma formation beneath the muscularis which was most severe in the ileum. Slight infiltration occurred in the stomach and the colon. The cells were predominantly lymphocytes and histiocytes. No acid-fast organisms were found.     

Incarcerated umbilical hernia in the horse: a case with a review of the literature

Umbilical hernias are common in foals. This article provides a review of the literature and presents a case of an 1.5-year-old Friesian mare with an incarcerated umbilical hernia. After reposition of the incarcerated intestine (with a lot of effort), the practising veterinarian referred the mare to the Department of Equine Sciences. Preperforative peritonitis was diagnosed, presumed to be caused by necrotic bowel. After laparotomy, this tentative diagnosis was confirmed. The necrotic part of the small intestine was resected and intensive medical treatment was started. Initially, the mare recovered well, but seven days after surgery her general condition deteriorated and she had to be euthanized. At necropsy, impaction of the stomach and rupture of the stomach wall were found. The impaction was probably a result of the generalized peritonitis.     

Small intestinal strangulation caused by Meckel's diverticulum in a horse

Necropsy of a 12-year-old Quarter Horse mare revealed a blind-end segment of intestine originating from the antimesenteric border of the ileum. The blind-end segment had looped around and strangulated the ileum and 3.5 m of the jejunum.     

Gigantic Cutaneous Myxoma at Equine Distal Limb

An extremely large-sized neogrowth of myxoma was observed at the cannon region in a 3-year-old Arabian mare. The mass developed during the course of 4 months. The mass mechanically hindered the animal movement, exposing the mare to multiple external injuries and subsequent blood loss. The clinical parameters, morphology, and hematological and histopathological examinations of the myxoma were recorded. The body condition score of the mare was 1. The hemogram revealed moderate to severe degree of anemia. Histopathological sections assessed after surgical removal identified the mass as a myxoma. To the authors’ knowledge, this is the first report of cutaneous myxoma at equine limb in an Arabian horse.     

Thecoma in a mare

A 4-year-old crossbred Thoroughbred mare was referred to the University of Tehran Veterinary Medical Teaching Hospital for evaluation of a mass in the pelvic cavity. The mare had been partially anorectic and pyrexic. On clinical examination, the mare was thin and depressed, with body temperature of 38°C, a pulse rate of 38 beats/minute, and a respiratory rate of 10 breaths/minute. Palpation per rectum revealed a large, smooth and tense mass in the anterior part of the pelvic cavity. Ultrasound examination confirmed the presence of a soft tissue mass with a thick wall. The inner surface of the mass had a villous-like appearance. The stroma of the mass was mottled, with accumulation of speckled and hypoechoic to slightly hyperechoic fluid. Hormone assays revealed low serum concentration of testosterone. Serum progesterone concentration indicated that active luteal tissue and serum estradiol concentration was 24 pg/ml. On histological examination, the sections from the tumor were composed of oval- or spindle-shaped cells loosely arranged in diffuse sheets or irregularly interlacing fascicles. On the basis of these histological findings, the large tumor mass of the left ovary was considered to be a thecoma. To our knowledge, the details of the clinical, ultrasonographic, endocrinologic, and histologic findings of this tumor in the mare have not been described in the veterinary literature.     

Small intestinal pseudodiverticulosis in a pony mare

A 14-y-old pony mare was referred after 30-d duration of intermittent pyrexia, anorexia, weight loss, and change in manure consistency. Physical examination revealed a palpable but reducible ventral abdominal mass. Transabdominal ultrasonography revealed multiple distended, hypomotile, and thickened small intestinal loops in close approximation with numerous, well-defined, hyperechoic masses. There was a large amount of echogenic peritoneal fluid; abdominocentesis revealed a neutrophilic and macrophagic inflammatory exudate, and a mixed bacterial population was cultured. Given the poor prognosis, the mare was euthanized. The autopsy findings included a large abdominal abscess, serosanguineous peritoneal fluid with fibrin strands, and ~50 outpouches communicating with the lumen and extending from the anti-mesenteric aspect of the duodenum, jejunum, and ileum. These structures were classified as pseudodiverticula based on the histologic absence of the tunica muscularis layer of the intestinal wall. Pseudodiverticula should be included as a differential etiology in horses when clinical signs consistent with colic, diarrhea, or weight loss are recognized and, when on examination, one or more organized masses are palpated or visualized on transabdominal ultrasound, as well as visualization of small intestinal loops with thickened walls.     

EQUINE HERPESVIRUSES: Type 3 as an Abortigenic Agent

The inoculation of equine herpesvirus type 3 (EHV3) strain 65/61 into the amniotic cavity of a mare 6-7 months pregnant resulted in abortion 11 days later. Following abortion typical lesions of coital exanthema were not observed in the genital tract of the mare, nor was EHV3 isolated from her. Serological evidence, however, indicated that the mare was infected with EHV3 following inoculation. Grossly the foetal disease was characterised by placentitis, focal ulcerative dermatitis, focal necrosis of the lungs and a striking diptheritic gastritis. Histological findings were interstitial pneumonia, diffuse hepatitis, generalised myositis, extensive vascular necrosis and degeneration of a range of epithelial cells. EHV3 was isolated from the placenta and placental fluids, stomach fluid, pooled thoracic and abdominal fluid, skin, lung, spleen and small intestine of the foetus.     

Colonic adenocarcinoma with osseous metaplasia in a horse

Rectal palpation of a 30-year-old mixed-breed mare with chronic weight loss and intermittent, refractory abdominal pain revealed a mass in the right caudoventral portion of the abdomen. Hematologic and serum biochemical findings were normal except for slight mature neutrophilia and mildly high alkaline phosphatase activity and total bilirubin concentration. Cytologic examination of a specimen obtained by abdominocentesis revealed equal numbers of nondegenerative neutrophils and macrophages, but no evidence of neoplastic cells. The mare continued to have signs of abdominal discomfort and was euthanatized. Necropsy revealed a large mass at the junction of the right dorsal colon and transverse colon, and several smaller masses in the liver. Histologic characteristics of the small-colon mass were consistent with colonic adenocarcinoma with osseous metaplasia.     

Entrapment of the small colon through a mesocolic rent in a mare

A 6-year-old mare was presented for acute abdominal pain unresponsive to analgesics. Exploratory laparotomy revealed entrapment of the small colon through a 12 cm rent in the mesocolon. The incarcerated small colon was manually reduced and the rent in the mesocolon was sutured closed. The mare made excellent postoperative recovery and was discharged from the hospital 4 days later. The cause of the rent, which was chronic in appearance, is unknown.     

Pythiosis with bone lesions in a pregnant mare

A 9-year-old pregnant mare was referred for evaluation of a nonhealing wound of 8 weeks' duration on the lateral aspect of the left forelimb. A soft tissue mass encircled the proximal two thirds of the metacarpus; radiography revealed a moderate periosteal reaction affecting metacarpal bone i.v. Histologic and immunohistochemical examinations revealed eosinophilic granulomatous inflammation and Pythium sp in the soft tissues. The mare was treated for 12 days with antimicrobials, medicated wound dressings, debridement, and i.v. administration of sodium iodide; radiography revealed progression of the bone lesions. The mare was treated by regional arterial perfusion with miconazole and excision of affected soft tissues and the distal two thirds of metacarpal bone i.v. The mare recovered without complications and gave birth to a healthy foal. Regional perfusion of antifungal agents provides high concentrations in soft and osseous tissues and permits use of low dosages of agents administered by other routes, which reduces cost, adverse effects, and teratogenic effects.