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.     

Pleural effusion secondary to thoracic metastatic mammary adenocarcinoma in a mare

A 17-year-old Quarter Horse mare was examined nearly 3 years after excision and cryotherapy of a papillary mammary gland adenocarcinoma. The mare had been used for pleasure riding since surgery, but had recently developed progressive dyspnea. The mare had clinical evidence of pleural effusion, but died before further clinical examination and treatment were instituted. Necropsy revealed deep mammary masses with similar nodules in the deep inguinal, renal, and mediastinal lymph nodes and in the lungs, pericardium, visceral and parietal pleurae, and left ovary. The masses were identified as papillary mammary gland adenocarcinoma. Large volumes of free pleural and peritoneal fluid were detected. The pleural fluid contained similar neoplastic cells that could have been readily detected by exfoliative cytologic examination had the mare survived.     

Ultrastructure of the horse tongue: further observations on the lingual integumentary architecture

This investigation examined primarily epidermal specializations of the adult horse tongue by light, scanning and transmission electron microscopy. Samples were collected from seven regions of the normal tongue of various breeds of horse. The filiform papillae, present on the dorsal and lateral aspects but not the ventral aspect of the tongue, were short, slender and finger-like structures with variable-shaped terminae. The epidermal thickness and height of dermal ridges were reduced on fungiform and vallate papillae, but tissue architecture and keratinocyte ultrastructure of most of the lingual epidermis corresponded to the common mammalian epidermal paradigm. One unique finding was the highly localized clustering of epidermal cells with exceptionally high content of PAS-negative trichohyalin cytoplasmic granules at a location atop the dermal ridges and beneath the base of filiform papillae. These granular cells were immediately subjacent to clusters of clear, non-granulated epidermal cells. It is believed that this integumentary specialization may enhance the structural strength at this localized site of the tissue architecture, in relationship to the mechanical papillae.     

Bilateral ovarian adenocarcinoma in a mare causing haemoperitoneum and colic

Abstract

CASE HISTORY: A 13-year-old Thoroughbred mare was presented with a history of mild colic over 3 days. This colic had acutely exacerbated and was unresponsive to analgesic treatment, and was referred to Massey University Veterinary Teaching Hospital.

CLINICAL FINDINGS: On examination the heart rate was 100 beats per minute, and mucous membranes were pale and tacky. A large mass was detected on transrectal palpation in the caudal abdomen to the left of midline. Explorative laparotomy revealed severe haemoperitoneum and several masses that were associated with the reproductive tract. The mare was then subject to euthanasia. On post-mortem examination, adjacent and attached to each ovary were soft, lobulated dark red masses up to 200 mm in diameter. Similar masses were present in the omentum and on the peritoneal surface of the diaphragm and the serosa of the spleen and liver. Histopathology revealed that the neoplastic component of the masses comprised proliferating cuboidal to columnar cells forming disorganised acini and cords separated by dense collagenous stroma. Immunohistochemistry showed the neoplastic cells were positive for cytokeratin AE1/AE3 and vimentin, but negative for cytokeratin 7 and inhibin α.

DIAGNOSIS: Bilateral ovarian adenocarcinoma with transcoelomic metastasis and terminal decompensation due to rupture of a neoplastic mass and consequent haemoperitoneum.

CLINICAL RELEVANCE: To the authors' knowledge, bilateral ovarian adenocarcinoma has not been previously reported in a horse. Ovarian adenocarcinoma should be considered when horses present with haemoperitoneum and colic. Further research is required on the immunohistochemical differentiation of adenocarcinoma of ovarian and intestinal origin in the horse.     

Teratocarcinoma of the ovary in a mare

A 5-year-old Appaloosa mare had a history of mild intermittent abdominal discomfort and clinical signs that were suggestive of intestinal obstruction. Palpation per rectum revealed a large mass attached to the left uterine horn, with smaller masses extending dorsally and cranially and causing constriction of the rectum. At necropsy, numerous multilobulated masses were observed in the abdominal cavity and several nodules were seen in the lungs. The left ovary was large and contained both cartilage and hairlike material. Sections from all masses had similar histologic features and confirmed the tentative diagnosis of teratocarcinoma.     

Computed Tomography and Magnetic Resonance Imaging of an Epidermoid Cyst in a Foot of a Horse

An 18-year-old Quarter Horse mare was evaluated because of moderate left forelimb lameness of 4 weeks’ duration. The clinical evaluation and diagnostic perineural analgesia localized the lameness to the distal portion of the left forelimb. There was swelling on the dorsal and lateral aspect of the coronary band. Radiography, ultrasound, magnetic resonance imaging, and computed tomography of the foot revealed circumscribed well-capsulated soft tissue mass causing a focal deformation of the dorsolateral border of the middle phalanx. The treatment aimed to remove the mass surgically and stabilized the interphalangeal joint, but the owner elected human euthanasia before treatment attempt. Histopathology diagnosis was an epidermoid cyst, which was characterized by multilayers of keratin surrounded by stratified squamous epithelium. Although rare, an epidermoid cyst should be considered as a differential diagnosis for space-occupying mass in horses’ foot that develops chronic lameness after trauma. This report describes the multimodality appearance of the epidermoid cyst.     

Cutaneous Hemangiosarcoma in a Dog

A male golden retriever of unknown age presented with multiple cutaneous and subcutaneous masses from the left elbow to the digits. Histopathologically, multiple tumor foci had formed from the dermis to the subcutaneous tissue. Tumor foci consisted of a vascular structure, alveolar structure and solid proliferative area. The borders among these areas were not clear. Some neoplastic cells resembled a mature endothelium, while others were large pleomorphic cells. Immunohistochemically, the tumor cells were usually strongly positive for CD31 and often positive for PROX-1, the lymphatic endothelial cell marker. Based on these findings, the tumor was diagnosed as a hemangiosarcoma with lymphatic differentiation.     

Malignant giant cell tumor of soft parts in a mare

Two subcutaneous masses were removed from the elbow of a mare. Histologically they were composed of islands of polygonal to plump spindlelioid cells with large nuclei, coarsely stippled chromatin, and eosinophilic cytoplasm. Findings were diagnostic for a malignant giant cell tumor of soft parts, a rare tumor with a fair prognosis.     

Progression of mycosis of the auditory tube diverticulum (guttural pouch) after arterial occlusion in a horse with contralateral temporohyoid osteoarthropathy

CASE DESCRIPTION: A 6-year-old Appaloosa mare was examined because of inappetance, difficulty eating, and swelling and mucopurulent discharge in the right eye. CLINICAL FINDINGS: Results of a CBC and serum bio-chemical analysis revealed no important findings. Ophthalmologic examination revealed scarring and ulceration of the superficial layers of the cornea. Endoscopic examination of the upper portion of the respiratory tract and auditory tube diverticula (guttural pouches) revealed abnormal thickness of the right stylohyoid bone and a plaque suggestive of mycotic growth on the left internal carotid artery. Radiographic examination revealed right-sided otitis media. Temporohyoid osteoarthropathy in the right guttural pouch and mycosis in the left guttural pouch were diagnosed. TREATMENT AND OUTCOME: Ceratohyoidectomy of the right stylohyoid bone was performed, and the left internal carotid artery was occluded via placement of stainless steel spring embolization coils. The mare regained the ability to eat without difficulty and improved clinically for approximately 4 weeks. However, the mare returned to the medical center 53 days after surgery with left-sided Horner syndrome, atrophy of the right side of the tongue, and a 3-week history of dysphagia and weight loss. Endoscopic evaluation revealed progression of mycotic growth in the left guttural pouch. The mare was euthanatized. CLINICAL RELEVANCE: Although the mycotic lesion in the left guttural pouch was an incidental finding at the time of initial examination, the lesion progressed to cause dysphagia and Horner syndrome after occlusion of the left internal carotid artery, a treatment that is typically associated with resolution of guttural pouch mycosis. Arterial occlusion is not necessarily a reliable method of resolving guttural pouch mycosis.     

Intravascular papillary endothelial hyperplasia of the conjunctiva in a horse

Objective Vascular tumors of the conjunctiva in the horse are rare. We present a unique case of an intravascular papillary endothelial hyperplasia of the conjunctiva. Animal studied Horse. Procedures Case report. A 6‐year‐old‐mare presented with a red mass in the conjunctiva of the left eye. After complete ophthalmologic examination the lesion was excised. The tissue was processed for light microscopy and studied histopathologically. Results Pathologic examination revealed a nonencapsulated vascular lesion composed of confluent vascular spaces filled by multiple papillary structures composed of a central collagenous core lined by hyperplastic endothelial cells. There was neither atypical endothelial cell nor mitotic activity. Conclusions Intravascular papillary endothelial hyperplasia is a benign proliferative lesion that should be differentiated from malignant vascular tumors.     

Haemoabdomen secondary to granulomatous periarteritis due to parasitism with Halicephalobus gingivalis in a mare

A 22‐year‐old Quarter Horse mare exhibited neurological signs consisting of head pressing, central blindness, minimal ataxia and dysphagia. Despite treatment, the mare collapsed and died shortly after onset of signs. On necropsy, there were approximately 15 l of free blood in the abdominal cavity. A 12 × 4 cm diameter, irregularly‐shaped, nodular, firm, tan/yellow mass was found adhered to the outer surface of the right lateral aspect of the caudal abdominal aorta. A similar mass also affected the caudal aspect of the right kidney. Histopathology of the aortic and renal masses revealed multiple coalescing granulomas containing intralesional nematodes compatible with Halicephalobus gingivalis. Inflammatory cells disrupted the aortic tunica adventitia as well as the outer tunica media. Similar exudate also affected the cerebrum, cerebellum and brainstem. Polymerase chain reaction amplification and sequencing of a portion of the large subunit ribosomal ribonucleic acid gene were performed using previously published primers for H. gingivalis to confirm the identity of the nematode. Although rupture of a blood vessel could not be demonstrated grossly, the histological findings suggest that inflammation may have breached a small calibre artery and caused the haemoabdomen.     

Standing removal of the proximal aspect of an olecranon fracture in a mature horse

A 12‐year‐old 450 kg Argentine polo mare presented with a dropped elbow and an unwillingness to bear weight after being kicked by another horse on the lateral aspect of the upper left forelimb. The mare was subsequently diagnosed with a displaced olecranon fracture that did not readily conform to the standard classification systems. Referral for surgical treatment involving open reduction and internal fixation was declined due to financial constraints. Due to the mare being unsuitable for breeding, and conservative treatment of displaced olecranon fractures being deemed to have an overall poor prognosis for return to full athletic performance, another treatment option was sought. Given the fracture configuration, standing surgical removal of the large proximal fragment was performed. The mare returned to full athletic performance 12 months post operatively without lameness. This case report describes an alternative treatment option for selected olecranon fractures.     

Elevated Serum Anti-Müllerian Hormone in an Arabian Mare with Granulosa Cell Tumor

Anti-Müllerian hormone (AMH), produced by granulosa cells, has been reported to be elevated in mares with granulosa cell tumor. A 13-year-old Arabian mare was referred after 3 years of infertility. Rectal and ultrasonographic examination revealed enlargement and multicystic appearance of the left ovary. The mare had substantially higher concentration of AMH (21.6 ng/mL) compared with normal cyclic mares (n = 5; 0.36 ± 0.02 ng/mL). Testosterone (50 pg/mL) concentration was also elevated, but progesterone concentration (0.4 ng/mL) was lowered. Accordingly, the mare was presumptively diagnosed with granulosa-theca cell tumor and a left ovariectomy implemented using ventral midline approach under general anesthesia. Histopathological examination confirmed the diagnosis of granulosa-theca cell tumor. Serum concentrations of AMH decreased to 2 ng/mL and 0.5 ng/mL 2 and 4 weeks after tumor removal, respectively. In conclusion, the current report presents confirmatory evidence that evaluation of serum AMH could be useful for diagnosis of granulosa cell tumor in mare.     

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.     

Pleomorphic sarcoma with giant cells infiltrating the infraorbital canal in an aged Thoroughbred mare

A 27-year-old Thoroughbred mare presented for computed tomography (CT) of the head following a 3-month history of facial swelling at the infraorbital foramen, unilateral self-mutilation and head-shaking. Standing CT imaging showed soft tissue attenuation surrounding the infraorbital canal, with extensive bony lysis of the canal and maxillary bone at the infraorbital foramen. The mare was subjected to euthanasia, and post-mortem examination revealed a proliferative tan soft tissue mass overlying the infraorbital nerve. A histopathological diagnosis of pleomorphic sarcoma with giant cells was made. Immunohistochemical analysis failed to fully elucidate the mesenchymal cell of origin of the sarcoma. Pleomorphic sarcoma with giant cells involving the infraorbital canal of the horse has not been previously described. This case highlights chronic subtle behavioural changes attributable to this neoplasm prior to the development of clinical signs and the utility of advanced imaging in the diagnosis.     

Thoracotomy for repair of a large dorsal diaphragmatic hernia in an 18‐year‐old mare

An 18‐year‐old Arabian‐mix mare was presented with a history of severe colic. Emergency exploratory celiotomy revealed diaphragmatic hernia, with a large rent in the left dorsal aspect of the diaphragm and large colon volvulus. Attempts to close the defect in the diaphragm in dorsal recumbency were unsuccessful. Therefore, a thoracic approach through lateral thoracotomy was elected, and a mesh was attached to the diaphragm using skin staples. While in dorsal recumbency, the mare suffered from significant respiratory acidosis. Thus, the mare was tilted into reverse Trendelenburg (30° head upward) and ventilation improved markedly. The mare recovered uneventfully, and was doing well 5 years after surgery.     

Surgical resection of a dysgerminoma in a mare

A mare was referred for further evaluation of a mass found in the left caudal abdomen during a routine postpartum reproductive palpation. The mare was clinically normal with no history of health problems. Ultrasonographic examination of the mass confirmed its presence, but the origin of the mass could not be accurately determined. Routine haematology and serum biochemistry results were within normal limits. The mare was initially treated conservatively with antibiotics, but the mass continued to increase in size, so it was surgically excised. The mass involved the left ovary. The mare showed transient abdominal pain after surgery, but developed no other complications and was in foal 7 months later. On histology, the mass was diagnosed as a dysgerminoma, a rare ovarian tumour of germ cell origin.     

Morphology of the dorsal lingual papillae in the Japanese macaque and Savanna monkey

The dorsal lingual surfaces of infant Japanese macaque (Macaca fuscata) and adult savanna monkey (Cercopithecus aethiopus) were examined by scanning electron microscopy. Filiform, fungiform, foliate and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue. The fungiform papillae were round in shape, and more densely distributed on the lingual apex. The foliate papillae were seen on the dorsolateral aspect of the tongue. The three vallate papillae were arranged like a triangle with the apex of the triangle directing caudally. Each papilla was surrounded by a groove. The rudiments of the fungiform, foliate and vallate papillae were visible earlier than those of the filiform papillae.     

Bilateral lymphosarcoma of the nictitating membrane in a Quarter Horse

A 21-year-old Quarter Horse mare presented for a mass of the right nictitating membrane. The entire right nictitating membrane was surgically removed and diagnosed as a mixed cell lymphosarcoma and squamous cell carcinoma. The horse had no systemic signs of lymphosarcoma. Approximately 1.5 years later, the horse presented with a similar mass in the left nictitating membrane. The entire left nictitating membrane was surgically removed and diagnosed as a mixed cell lymphosarcoma. In this case, complete surgical removal of the masses resulted in a cure. The horse has remained free of systemic lymphosarcoma for over 3 years.

Case report

A 21-year-old gray Quarter Horse mare was presented to the Kansas State University Veterinary Medical Teaching Hospital for evaluation of a mass involving the right nictitating membrane. The mass was first noticed 5 weeks before presentation and had been treated by the referring veterinarian with a topical steroid solution twice daily. Administration of the topical steroid caused some decrease in the swelling, but it quickly returned once medication was discontinued. The horse had no other medical complaints and appeared to be otherwise healthy. On ocular examination, chemosis of the third eyelid and conjunctiva of the right eye was evident. Direct and indirect pupillary light reflexes, Schirmer tear test, and intraocular pressures were normal in both eyes. Fluorescein stain uptake was negative in both corneas. Cranial nerve and vision examinations did not reveal any abnormalities. On further examination of the right nictitating membrane, a firm mass was palpated under and protruding from the palpebral conjunctiva (Fig 1). No other abnormalities were found on physical examination.