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Objectives: To describe dermoid cyst formation as an uncommon complication of the pinch grafting technique in horses., Study Design: Case report., Animal: A 8 year old Arabian gelding., Methods: Clinical presentation, imaging, treatment, and histopathology records were reviewed. The horse originally presented due to delayed healing of a laceration to the distal aspect of the metatarsus. The wound was treated initially with debridement and it was allowed to fill with healthy granulation tissue prior to pinch grafting. Two months after grafting, the horse started to show self-mutilation behavior targeting the wound site. Ultrasonographic examination revealed the presence of cystic lesions in the subcutaneous tissue in the wound bed and adjacent to the long digital extensor tendon., Results: Treatment involved surgical excision of the cysts, which resulted in a resolution of the self-mutilation episodes. The specimens were submitted for histopathological investigation, which revealed findings compatible with dermoid cyst formation, suspected to be secondary to the skin-grafting procedure., Conclusion: Dermoid cysts formation should be considered as a potential differential diagnosis for skin graft complications in horses., (© 2024 American College of Veterinary Surgeons.)

A 5-year-old neutered female mixed cat presented with reduced activity and ataxia of the hind limbs. Computed tomography and magnetic resonance imaging revealed an extradural mass compressing the spinal cord on the dorsal aspects from the 7th to 8th thoracic vertebra. Dorsal laminectomy was performed on the 7-8th thoracic vertebra and the cyst was totally removed, giving full resolution of the clinical signs. The cyst was diagnosed as a dermoid cyst. To our knowledge, this is the first report of feline dermoid cyst compressing the spinal cord that was diagnosed antemortem. The prognosis is favorable when the cyst is completely resected.

A 131-day-old male Japanese Black calf presented with a swollen right cheek from birth. Imaging examination revealed a cyst under the right buccal area and debris-containing fluid inside the cyst, and puncture aspiration revealed a mildly cloudy fluid containing hair and tissue fragments. Histological examination of the excised cyst revealed stratified squamous epithelium with skin appendages in the cyst wall, which was diagnosed as a dermoid cyst. In addition, some submandibular gland tissue was found within the cyst wall. After removal of the cyst, there was swelling in the same area, which resolved with steroid administration. Surgical treatment of buccal dermoid cysts should be performed with caution to avoid damage to adjacent salivary gland tissue.

Objectives: The aim of this multicentre retrospective study was to review the clinical data, outcomes and histopathological features of cats that had been treated for ocular surface dermoids., Methods: Thirteen cats from various private practices in France with a clinical diagnosis of ocular surface dermoid were included in the study., Results: The mean age of the study population at the time of diagnosis was 5 months. There were nine males and four females. Three different breeds were domestic shorthair (n = 7), Birman (n = 4) and Havana Brown (n = 2). Two of the four Birmans were related (same sire). The two Havana Browns were also related (same sire). All of the dermoids were unilateral. Five of the dermoids were strictly conjunctival. Four affected both the conjunctiva and the cornea. Three affected both the conjunctiva and the eyelid, and one was strictly corneal. They were located in various positions: temporal (n = 9), inferonasal (n = 1), dorsonasal (n = 1) and dorsotemporal (n = 1). The last dermoid was heterogeneous and involved the nasal, dorsal and temporal quadrants. Concurrent eye diseases were observed in five patients: four cats exhibited associated eyelid agenesis and one cat exhibited persistent iris-to-iris pupillary membranes. Ten dermoids were surgically excised with no recurrences. Surgery was not performed for three cats: one cat died a few days after diagnosis and two cats were lost to follow-up after initial presentation., Conclusions and Relevance: Ocular surface dermoids are a rare condition in cats that can be treated successfully by surgical excision. Although our study reports only a small number of cases, the observation of ocular surface dermoids in two related cats in two different breeds indicates that genetic transmission is likely.

Objective: To describe clinical features of dogs diagnosed with ocular dermoids at two veterinary teaching hospitals., Animals Studied: Retrospective case series of 44 dogs (49 dermoids) with ocular dermoids., Procedures: Medical records of dogs evaluated by the Cornell University and University of Pennsylvania ophthalmology services were evaluated to identify dogs with a clinical diagnosis of ocular dermoids between 2004 and 2018, and 2011 and 2018, respectively. Signalment, historical, and clinical details were recorded, including dermoid location, concurrent diseases, treatment, histopathologic findings, and outcome., Results: A total of 49 ocular dermoids, involving 47 eyes, were diagnosed in 44 dogs. The mean ( standard deviation) age of the study population at the time of diagnosis was 1.19 years (1.85 years). Of the 44 dogs evaluated, 28 (63.6%) were male and 30 (68.2%) were intact at time of diagnosis. Twenty-two different breeds were represented in the study, with mixed breed, French Bulldog, and Shih Tzu being the most common. Twenty-two dermoids were categorized as limbal (44.9%), 14 as eyelid (28.6%), eight as corneal (16.3%), and five as conjunctival (10.2%). Concurrent ocular findings were noted in 29 of the 47 eyes (61.7%), including corneal pigmentation, epiphora, and conjunctival hyperemia. Nine dogs (20.5%) suffered from concurrent systemic disease, with the majority being cardiac in origin. A total of 34 dermoids (69.4%) were surgically excised with no recurrences., Conclusions: Ocular dermoids are an uncommon condition in dogs. Concurrent congenital cardiac disease was relatively common in the dogs of this study. Surgical excision of dermoids was curative., (© 2019 American College of Veterinary Ophthalmologists.)

A 6 mo old male castrated bloodhound-Rhodesian ridgeback mix (case 1) presented for a mass suspected to be a dermoid sinus in the thoracolumbar region, and a 2.5 yr old male castrated Rhodesian ridgeback (case 2) presented for a mass suspected to be a dorsal cervical dermoid sinus. Both dogs underwent single-phase contrast computed tomography (CT) to characterize the extent of the dermoid sinus prior to surgical excision. Soft tissue and bony abnormalities of the vertebral spine associated with the dermoid sinuses were confirmed in both dogs prior to surgery, demonstrating communication with the dura of the spinal cord. Surgical exploration and excision of the dermoid sinus was performed in each dog, including partial laminectomy. Both cases had resolution of the sinus and an uncomplicated recovery. These cases show that single-phase contrast CT was accurate in characterizing the extent of the dermoid sinus without adjunctive tests or more invasive diagnostics. Single-phase contrast CT should be considered as a preoperative method to characterize the extent of dermoid sinuses, avoiding the risks associated with myelography or fistulography and the expense of MRI. This is also the first report of a dermoid sinus in the thoracolumbar region and the first in a bloodhound and Rhodesian ridgeback mix.

A 6-month-old Leine sheep was presented because of dermal tissue located on the left eye. During the first examination, the animal was clinically silent, apart from the deformed eye. A corneal and conjunctival dermoid and blindness of the left eye were diagnosed. Over a period of a year, the animal displayed conjunctivitis and inflammation of the affected eye. Furthermore, the sheep did not develop according to its age. During histopathological examination of the euthanized animal, microphthalmia and aphakia of the left eye were found in addition to the dermoids. Dermoids are described in humans and in different domestic animals. They can be combined with other congenital malformations. In sheep, dermoids are rarely diagnosed or reported in the literature., Competing Interests: Die Autoren bestätigen, dass kein Interessenkonflikt besteht., (Georg Thieme Verlag KG Stuttgart · New York.)

A 20-month-old male miniature dachshund was evaluated for a 10-week history of intermittent stranguria, pollakiuria, haematuria and obstructive urolithiasis. Retrograde urethrocystography revealed a subcutaneous saccular structure in the perineal area connected to the intrapelvic urethra associated with urolithiasis. After excision of the perineal saccular structure, microscopical examination confirmed the presence of transitional epithelium lining the diverticulum, with isolated submucosal smooth muscle bundles. This structure was attached to another saccular structure lined by stratified squamous keratinizing epithelium with hair follicles, sebaceous glands and apocrine glands. An incomplete urethral duplication with dermoid cyst was diagnosed. The dog recovered uneventfully from surgery and was still urinary continent and free from clinical signs 5 months after surgery. To the authors' knowledge this is the first report of an incomplete urethral duplication with a dermoid cyst and concurrent obstructive urolithiasis in a dog., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objective: This case series describes the computed tomography (CT) and surgical findings of nine dogs with dermoid sinuses., Methods: Medical records were reviewed and summarised., Results: CT with intravenous contrast showed a superficial, peripherally contrast-enhancing, fluid-filled structure with a contrast-enhancing, soft tissue-attenuating tract that extended from the skin through the dorsal midline soft tissues, often to the level of the nuchal ligament. The tract often extended in an oblique direction to the nuchal ligament, but the tract ventral to the nuchal ligament, found at surgery, was not always discernible on CT. The dermoid sinuses were excised from all dogs. At surgery, the tract often extended ventral to the nuchal ligament, terminating on the vertebra. The most ventral aspect of the tracts involved a fibrous strand extension of the sinus, which was not discernible on CT., Conclusion: Preoperative CT facilitated the diagnosis of a dermoid sinus and directed surgical planning; however, careful dissection beyond the nuchal ligament is imperative for complete excision., (© 2016 Australian Veterinary Association.)

Background: Dermoid sinus is an uncommon epithelial-lined fistula that may be associated with vertebral malformations. In humans, Klippel-Feil syndrome (KFS) is a rare condition characterized by congenital cervical vertebral fusion and may be associated with other developmental defects, including dermoid sinus. The present case report describes an adult Dachshund with cervical and cranial thoracic vertebral malformations as well as thoracic limb malformations resembling KFS with a concurrent type IV dermoid sinus., Case Presentation: A 1.5 year-old Dachshund with congenital thoracic limbs deformities and cervical-thoracic vertebral malformations presented with cervical hyperesthesia, rigidity of the cervical musculature and tetraparesis. Neurologic, radiographic, and computed tomography (CT) (2D, 3D, CT fistulography) examinations revealed skeletal anomalies, a dermoid sinus in the cranial thoracic region and epidural gas within the vertebral canal. Surgical resection and histopathological evaluation of the sinus tract were performed and confirmed a type IV dermoid sinus. The clinical signs progressively recovered postoperatively, and no recurrent signs were observed after 6 months of follow-up., Conclusions: Cervical vertebral malformations associated with limbs anomalies have not been reported in dogs and may represent a condition similar to KFS in humans. KFS can occur concurrently with other congenital conditions including dermoid sinus and should be included among the complex congenital anomalies described in dogs.

A 2-year-old male French bulldog was presented for investigation of lumbosacral pain and hindlimb ataxia associated with urinary and fecal incontinence. Survey radiography, myelography, and computed tomography images were suggestive of a dermoid sinus with associated spina bifida. Surgical intervention led to a resolution of pain and neurological deficits. Histopathological analysis of the excised tissue was compatible with a myelomeningocoele of the 7th lumbar vertebra.

Dermoid sinus, a congenital malformation of neural tube development, has been reported in humans and several animal species including dogs. It is typically found in the dorsal midline and commonly occurs in the Rhodesian Ridgeback breed. A case of multiple dermoid sinuses in the fronto-occipital region is described. An 11-month-old, intact female Saint Bernard dog was presented with a 2 day history of discharge from a large irregular subcutaneous mass in the fronto-occipital region. The dog was otherwise healthy. The dog had two circular skin lesions (approximately 4 × 4 and 4 × 2 cm diameter) surrounded by multiple irregular elevated masses. The masses had multiple small openings on the skin surface with tufts of hair protruding from the apertures. The masses were surgically removed, and the diagnosis of multiple dermoid sinuses was confirmed by histological examination. Histopathological examination showed multiple, variably sized, spherical to tubular cysts expanding the dermis and subcutis. Cysts were filled with hair shafts and lamellar keratin and were lined by a stratified squamous epithelium. Sebaceous and apocrine gland adnexal structures were also observed. To the best of our knowledge, this is the first reported case of multiple dermoid sinuses of two different types in the head of a Saint Bernard dog.

A two-year-old male German shepherd dog was admitted to Shahid Bahonar Veterinary Hospital with clinical signs that included lethargy, anorexia, vomiting, abdominal pain and dehydration. Physical examination revealed nothing significant. Routine paraclinical tests only revealed a stress leukogram. Radiography revealed a mass in the stomach. Whilst performing a laparotomy, the surgeon observed an unusual mass in the subserosal layer of the proximal part of the jejunum. The histopathology of the mass revealed some scattered sebaceous and sweat glands associated with the cyst wall that confirmed the diagnosis of a dermoid cyst. Intestinal dermoid cysts are very rare and to our knowledge this is the first report of an intestinal dermoid cyst in a dog.

An 8-year-old Gypsy Vanner gelding presented to the University of Florida Ophthalmology service for the evaluation of chronic, recurrent corneal ulcers behind the third eyelid of the right eye. On ophthalmic examination, a cluster of aberrant hairs was identified growing along the margin of the third eyelid. This portion of third eyelid was surgically excised, and histopathology identified the haired tissue as a dermoid. Chronic keratitis secondary to a third eyelid dermoid was diagnosed, and excision appeared curative at 6 months post-operative follow-up., (© 2012 American College of Veterinary Ophthalmologists.)

A 6-month-old female spayed domestic shorthair cat was presented for evaluation of a focal subcutaneous swelling on the dorsal neck at the level of atlas. The magnetic resonance imaging and surgical treatment of a dermoid sinus associated with the cervical vertebrae is described. To the authors' knowledge, a dermoid sinus in this location has not been described previously in the cat. The prognosis following surgical resection appears favorable., (Copyright © 2011 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.)

A 2-year-old female Yorkshire Terrier dog presented with neurological deficits. Magnetic resonance imaging revealed an 8 mm in diameter mass centered left of midline arising from the quadrigeminal cistern, with a fatty or proteinaceous content. A further fat signal intensity focus was present in the tip of the temporal horn of the right lateral ventricle, in keeping with a "floating" fat embolus within the cerebrospinal fluid. A ruptured dermoid cyst was diagnosed. Within the frontal lobe on both sides were ill-defined and extensive high T2 signal areas, with mass effect within the white matter, and asymmetrical contrast enhancement following intravenous injection of gadolinium. Postmortem gross and histological examination confirmed the mass in the quadrigeminal cistern to be a dermoid cyst. In addition, severe multifocal necrotizing granulomatous leukoencephalomyelitis was found in the corona radiata and spinal cord. The relationship between these 2 pathologies is discussed.

A Dalmatian was presented with a subcutaneous swelling in the dorsal midline between the eyes. No opening in the skin was identified at the dorsal nasal planum and there was no discharge. Positive contrast sinography showed contrast material filling a cyst that extended to the frontal bone. At surgery, the cyst had a tubular shape and was embedded in a fibrous dermal tissue strand running into the bony nasal septum. The nasal dermoid sinus cyst was surgically removed by limited dorsal rhinotomy, followed by excision of the remaining strand from a bony recess in the lamina perpendicularis ethmoidalis. It is proposed that this nasal dermoid cyst that extends through the frontal bone with no sinus tract is classified as a type V subtype c., (© 2011 British Small Animal Veterinary Association.)

A 3-day-old, male red deer (Cervus elaphus) with bilateral microphthalmia was found dead in the Western Alps in northern Italy. No other gross alterations were present. Ocular globes were formalin fixed and processed for histology. In both eyes, a large cyst, filled with keratin and lined by squamous epithelium admixed with sebaceous glands and hair follicles, expanded the anterior chamber. A mass composed of spindle cells and small tubules, embedded in myxoid ground substance, filled the vitreal chamber. No lens tissue was found, leading to the speculation that the dermoid cystic structures originated from abnormal differentiation of the primitive ectodermal lens vesicle. Immunohistochemistry with a panel of antibodies against cytoskeletal proteins revealed neural and mesenchymal elements within the vitreal mass. A complex bilateral ocular dysgenesis, with microphthalmia, aphakia, and dermoid metaplasia of primitive lens vesicle was diagnosed. The latter finding was unusual and was previously documented only in Texel sheep (Ovis ammon), in which it was related to specific gene mutation on chromosome 23.

Transplantation of canine amniotic membrane (AM) in conjunction with a third eyelid flap was performed after the removal of large dermoids by keratectomy and conjunctivectomy on 7 eyes of 7 dogs. Corneal epithelialization was completed within 2 weeks after the transplantation. Five eyes attained normal transparency of the cornea within 5 weeks. Slight pigmentation of the bulbar conjunctiva at the limbus was observed in 1 dog that had pre-existing pigmentary keratitis. Neovascularization and scarring of the cornea and impaired vision were not found in any dogs at 8 weeks after the transplantation. In conclusion, transplantation of canine AM can promote corneal healing after the excision of large dermoids in dogs.

A 2-year-old, male, Burmese cat was evaluated for chronic progressive hindlimb weakness, ataxia and urinary incontinence. Radiographic examination, myelography and magnetic resonance imaging defined congenital vertebral anomalies and a space-occupying intradural, extramedullary mass. A dermoid sinus was subsequently identified dorsal to the affected spine. Surgical excision of the tract necessitated a dorsal laminectomy and removal of a 1-cm diameter intradural dermoid sinus 'cyst' that contained hair and sebaceous debris. The cat recovered hindlimb function after surgery and remains asymptomatic 50 months after surgery except for a persistent inability to urinate voluntarily.

A 5-year-old spayed female cat was evaluated for hyperthyroidism based on an elevated free thyroxine (T(4)) measurement and bilaterally enlarged symmetric subcutaneous masses in the area of the thyroid glands. Physical examination revealed bilateral subcutaneous masses on either side of the cervical trachea. Blood was obtained for serum biochemical profile and thyroid function analysis. Mild hyperalbuminemia, mild hypercalcemia, and mildly increased alanine aminotransferase activity were identified. Serum concentrations of total and free thyroxine were within the reference interval. Cytologic analysis of fine-needle aspirates from one of the masses was suspicious for neoplasia. Nuclear scintigraphy revealed no abnormalities. Surgically obtained excisional biopsies of both masses were submitted for histopathology and diagnosed as bilateral dermoid cysts. After excisional biopsy, the patient recovered without incident. The histopathologic diagnosis of completely excised bilateral dermoid cysts indicated that no further medical or surgical intervention was required. This is the first report of a cat presenting with bilateral dermoid cysts in the area of the thyroid glands. Histopathologic examination was necessary to make a definitive diagnosis. Practitioners should include cysts in their list of differential diagnoses for ventral neck masses in cats.

The ophthalmologic, radiologic and surgical findings of a 2-year-old Scottish Highland Cattle heifer with a dermoid cyst within the bony part of the nasolacrimal duct and the successful treatment are presented.

CASE DESCRIPTION- 2 dogs and 1 cat underwent endoscopic-assisted intracranial procedures for lesion biopsy (1 dog and 1 cat) and definitive lesion removal (1 dog). CLINICAL FINDINGS- 1 cat was treated for an interhemispheric, pedunculated meningioma with an associated arachnoid cyst. Two dogs underwent endoscopic surgery procedures; 1 dog underwent removal of an intranasal dermoid cyst with extension to the olfactory bulb dura, and the other underwent lesion biopsy for histologic confirmation of suspected intracranial granular cell tumor. TREATMENT AND OUTCOME- Minimally invasive intracranial procedures were achieved by use of an endoscope to aid in lesion biopsy in a dog and a cat with neoplasia and complete lesion removal in 1 dog with a dermoid cyst. No obvious morbidity from the use of the endoscope was observed. Rapid recovery from surgery was seen in all 3 animals, and hospitalization times were a few days. CLINICAL RELEVANCE- In human and veterinary neurosurgery, minimally invasive surgical approaches for diagnosis and treatment are gaining in popularity. Minimally invasive techniques are used to achieve a decrease in surgical time, minimize brain exposure, and decrease postoperative recovery times. Keyhole and minimally invasive approaches require some degree of dexterity and knowledge of where the endoscope is in a 3-dimensional orientation and its relationship to the topography of an anatomic region. Anticipation of complications should allow for potential conversion to an open craniotomy. Use of the endoscope in minimally invasive procedures is associated with a steep learning curve to understand orientation, topography, and normal versus abnormal anatomy.

Subcutaneous dermoid cysts were identified in eight wild caribou (Rangifer tarandus) from widely dispersed locations in northern Canada and in one wild caribou from Alaska. The dermoid cysts from Canadian caribou were found among 557 diagnostic specimens that had been detected by hunters and submitted by resource officers and biologists between 1 January 1966 and 15 May 2007. All of the cysts were located in the cervical region, and five of nine cysts were found in the throat area. All of the animals for which the age was known were adult; males and females were equally represented. Dermoid cysts were not diagnosed in any of 1,108 white-tailed deer (Odocoileus virginianus), 293 mule deer (Odocoileus hemionus), 174 elk (Cervus elaphus), or 529 moose (Alces alces) examined during the same period at the Canadian laboratory.

A 5-day-old Angus x Hereford calf presented for bilateral haired masses on the eyes and nasolabial planum since birth. The masses were surgically excised from the inferonasal cornea and bulbar conjunctiva of both eyes and the left and right side of the dorsomedial nasolabial planum. Histopathology of the excised tissue confirmed bilateral corneoconjunctival dermoids with ectopic lacrimal glands, and bilateral nasal choristomas and ectopic nasal glandular tissue. Surgery was curative and healing was uneventful. Bilateral ocular dermoids in combination with nasal choristomas and ectopic glandular tissue have not been documented previously in cattle.

A 4-year-old Andalusian horse was presented for examination following a 3-month history of exophthalmos of the right eye and a soft swelling of the right supraorbital fossa noted after blunt head trauma. Ultrasonographic examination of the swelling showed an anecogenic mass of 5 cm in diameter involving the retrobulbar space. Centesis of the mass through the supraorbital fossa was performed and yielded a serous fluid with 7.2 g/dL of total protein and density of 1040. No cells were seen in the sample. A tentative diagnosis of cyst was made. The cyst was surgically removed and the definitive histologic diagnosis was retrobulbar dermoid cyst. No recurrence has developed 18 months following the complete removal of the cyst capsule. To the authors' knowledge, there are no previous reports of retrobulbar dermoid cysts in horses. Localization, causes and success of surgical treatment of dermoid cysts are discussed.

The dorsal hair ridge in Rhodesian and Thai Ridgeback dogs is caused by a dominant mutation that also predisposes to the congenital developmental disorder dermoid sinus. Here we show that the causative mutation is a 133-kb duplication involving three fibroblast growth factor (FGF) genes. FGFs play a crucial role in development, suggesting that the ridge and dermoid sinus are caused by dysregulation of one or more of the three FGF genes during development.

An eight-week-old, male Labrador retriever puppy was presented with an abnormal appearance of the left cornea, observed after the eyelids opened in the second week of life. Ocular examination showed a large central dermoid of the left cornea. The dermoid was excised by superficial keratectomy, and healing was uneventful. The dermoid was classified as a Mann's second type. To the authors' knowledge, a Mann's second type corneal dermoid has not previously been reported in a dog.

Clinical and histopathological findings of a congenital ocular dermoid cyst, located at the lower eyelid of a river female buffalo (Bubalus bubalis) calf were presented. A soft, fluctuant, non-tender, hyperaemic cystic mass was detected overlaying the left eye. Fine needle aspirate revealed filamentous debris with no malignant cells. The cyst was treated surgically by orbital exenteration and subsequently subjected to histopathological examination. The histopathological study disclosed a conjunctival dermoid cyst. This report is novel, in that; such ocular cyst has not previously been described in river buffalo calves.

Bilateral dermoid sinuses were identified on the parieto-occipital region of a Rottweiler. Diagnosis was confirmed by histological examination after successful complete surgical resection. The dermoid sinuses were independent with separate tracts. This unusual parasagittal location can be explained by craniofacial development: dermoid sinuses on the head could occur along the lines of embryological fusion and not only in the sagittal plane. A hypothesis of an origin at the level of the suture between the parietal and interparietal bones is possible in this case.

A five-month-old female Shih-tzu puppy was presented for repair of congenital choristoma in left eye. The patient was suffered from chronic epiphora and ocular discharge during 3 months. On ophthalmic examination, left eye revealed hyperemia in conjunctiva of the temporal canthus due to choristoma with hair. At surgery, the choristoma invaded by stromal layer of the cornea, and extended to limbus and conjunctiva. Based on the anatomical location and histopathological features of the removed tissue, the choristoma was diagnosed as corneal dermoid.

Superficial keratectomy was performed in a New Zealand White rabbit for a suspected limbic dermoid. Histology confirmed the diagnosis. Ocular dermoids have been reported in a variety of laboratory animals. This is the first report of a corneal dermoid in rabbits.

A five-year-old, entire female English bull terrier was presented with a six-week history of intermittent facial swelling and nasal pain, following an incident of nasal trauma. A small opening was present at the mucocutaneous junction on the dorsal nasal planum. Examination under general anaesthesia allowed catheterisation of this opening and confirmed the presence of a tract passing caudally. Plain radiographic examination of the region was unremarkable. Positive contrast sinography demonstrated contrast material filling a midline tract that passed caudally and subcutaneously towards the nasal bone. This tract was surgically excised. Histopathological examination of the excised tissue, together with the clinical findings, led to the diagnosis of nasal dermoid sinus.

Epidermal (infundibular) and dermoid cysts are unusual in the horse in contrast with other species. The diagnosis and treatment of six lesions in the dorsal midline of a three-year-old Thoroughbred-cross gelding is described. The lesions were believed to be congenital and presented asymptomatically but required attention because five of them were in the saddle region, thus preventing ridden exercise. Under general anaesthesia, the cysts were excised and subsequently examined histologically. The horse recovered uneventfully. This report is novel in that such midline cysts have not previously been described outside Australia and North America.

Clinical and histologic findings of conjunctival dermoids in two unrelated guinea pigs are described. The dermoids were treated surgically by resection with superficial lamellar keratectomy and corneal epithelial debridement. Histologically the dermis underneath a stratified squamous keratinized and variably pigmented epithelium consisted of multiple hair follicles, with clearly visible arrectores pilorum muscles, sebaceous glands and loose vascularized fatty tissue.

Objective: To describe the clinical and morphologic characteristics of nasal dermoid sinus cysts in the dog., Study Design: Retrospective clinical study., Animals: Six client-owned dogs., Methods: Medical records (1995 to 1999) of 6 dogs that had a discharging sinus in the midline of the nose removed surgically were reviewed for signalment, physical examination, surgical and histopathologic findings, and outcome., Results: Three golden retrievers, 1 springer spaniel, 1 cocker spaniel, and 1 Brittany spaniel with a history of intermittent discharge from a small opening in the midline on the bridge of the nose at the junction between the nasal planum and the skin were identified. The condition was unresponsive to antibiotic therapy, and previous surgical excision had been unsuccessful in 3 dogs. None of the dogs had any other congenital defects, and all dogs responded to complete surgical excision of the tract and cyst. On histopathologic examination of excised tissue, there were adnexal structures along a tract lined with stratified squamous epithelium, consistent with a developmental abnormality of ectodermal tissue., Conclusions: The lesions were diagnosed as nasal dermoid sinus cysts, similar to the congenital condition described in humans. Nasal dermoid sinus cysts are rare developmental defects related to abnormal development of the pre-nasal space and may extend into the cranial vault causing cerebral abscesses or recurrent meningitis. Complete surgical excision has a good prognosis., Clinical Relevance: This is a new condition that should be added to the surgical differential diagnosis for a discharging sinus over the external nares in dogs., (Copyright 2002 by The American College of Veterinary Surgeons)

A case of dermoid sinus is reported in a golden retriever. The skin lesion was characterised by a fistulous tract in the dorsal cervical region. Surgical dissection revealed a cyst connected by a fibrous cord to the seventh cervical vertebra.