Intramedullary Epidermoid Cyst in the Thoracic Spine of a Dog

A Case of Epicardial Epidermoid Cyst in a Crested Porcupine

The crested porcupine (Hystrix cristata) is present in central Italy with an estimated population of 1800 individuals. Despite the local abundance, little data are available on the diseases affecting free-ranging individuals. We describe a case of an epidermoid cyst (EC) in a male adult porcupine found in the municipality of Sovicille, province of Siena (Tuscany). At necropsy, a firm rounded nodule was noted on the left ventricle wall. Histological examination revealed a cystic formation lined by stratified squamous epithelium. The cyst was filled with lamellar keratin, while hair shafts were not present. The adjacent epicardium was infiltrated by lymphoplasmacytic cells in reaction to the rupture of the cyst with the spilling of keratinaceous debris. The lesion was diagnosed as a ruptured epicardial epidermoid cyst. EC are most commonly found in the skin, both in human and animal patients, though infrequently, they can occur in any internal organ. Cardiac EC has not been reported in domestic animals, and this is the first report of EC in a wild animal species. Clinical veterinarians should consider the possibility of similar cardiac lesions in captive subjects since the long lifespan of these rodents could allow the growth of the cyst with the compression of the adjacent tissues.

Spinal cord haemangiosarcoma in one dog - Case report

A 5-year-old intact female Shih Tzu was presented with acute onset of hind leg paralysis. The neurologic examination revealed severe T3-L3 myelopathy. The differential diagnoses included degenerative, anomalous, traumatic, inflammatory, vascular, metabolic, and neoplastic changes. The results of the paraclinical examinations and diagnostic imaging narrowed the list of differential diagnoses and, along with the patient's deteriorating condition, led to the owner's decision to euthanise the dog. The histologic findings of the spinal cord specimens indicated a tumour of the blood vessels formed by the proliferation of endothelial cells, which may present as either capillary or cavernous structures. In this case, the tumour was a capillary-type haemangiosarcoma. The primary site of proliferation could not be determined in this case because no mass formation was noted while performing the necropsy.

Case Report: Recurrence of an Extradural Spinal Epidermoid Cyst Following Surgical Excision in a Dog

Congenital epidermoid cysts are slow-growing, mass lesions caused by the abnormal inclusion of neuroectodermal tissue within the developing central nervous system. Subtotal excision of epidermoid cysts increases the risk of early recurrence of clinical signs. A 4-year-old female spayed boxer was presented with a 4-month history of ambulatory paraparesis and proprioceptive ataxia. Neurological examination localized a T3-L3 myelopathy. MRI revealed a T1 iso- to hypointense, T2 and FLAIR hyperintense, rim-enhancing mass at the level of the T9-T10 vertebrae resulting in extradural compression of the spinal cord. This was histopathologically confirmed as an extradural epidermoid cyst following subtotal excision. MRI performed 2 months post-operatively revealed a significant decrease of the lesion volume. The dog was neurologically normal following the surgery however re-presented 28 months later with recurrence of clinical signs. A 28-month post-operative MRI revealed substantial enlargement of the epidermoid cyst. The dog was subsequently taken for repeat decompressive surgery. At 6 months from the repeat surgery, the dog was neurologically static with mild proprioceptive deficits. The case report highlights the clinical and MRI features of a recurrent extradural spinal epidermoid cyst treated by subtotal excision.

Type IV dermoid sinus, intramedullary dermoid cyst and spina bifida in a Cane Corso

A 1-year-old male Cane Corso was presented for progressive hindlimb neurologic deficits, with a history of suspected recurrent meningitis. Physical examination and advanced diagnostic imaging findings were suggestive of a thoracic dermoid sinus extending into the dura mater, and spina bifida. After initial medical treatment, the lesion was surgically excised, and the presence of an intramedullary cyst in continuation with the dermoid sinus was confirmed, requiring partial durectomy and myelotomy for removal. Histopathological examination of the excised tissue confirmed the diagnosis of a dermoid sinus associated with an intramedullary dermoid cyst. After surgery, the dog temporarily declined neurologically but then showed progressive neurological improvement. This report describes presentation and successful surgical treatment of a type IVa dermoid sinus associated with an intramedullary dermoid cyst and spina bifida in a dog.

Cystic Abnormalities of the Spinal Cord and Vertebral Column

Cystic lesions of the vertebral column and spinal cord are important differential diagnoses in dogs with signs of spinal cord disease. Synovial cysts are commonly associated with degenerative joint disease and usually affect the cervical and lumbosacral regions. Arachnoid diverticulum (previously known as cyst) is seen in the cervical region of large breed dogs and thoracolumbar region of small breed dogs. This article reviews the causes, diagnosis, and treatment of these and other, less common, cystic lesions.

Intranasal epidermoid cyst causing upper airway obstruction in three brachycephalic dogs

This case report describes three brachycephalic dogs with intranasal epidermoid cysts that were causing additional upper airway obstruction. Although epidermoid cysts have been described in several locations in dogs, to the authors' knowledge intranasal epidermoid cysts have not been previously reported. All dogs had mucopurulent to haemorrhagic nasal discharge. Magnetic resonance imaging of the head revealed the presence of unilateral or bilateral intranasal cystic lesions obstructing the nasal cavities partially or completely, with atrophy of the ipsilateral nasal turbinates. The cystic lesions were surgically excised in all dogs using a modified lateral alveolar mucosal approach to the affected nasal cavity. Aerobic, anaerobic and fungal culture of the cystic contents were negative and histology of the excised tissue was consistent with a benign intranasal epidermoid cyst in each dog. Upper airway obstruction was clinically improved in two dogs.

Epidermoid cysts of the rumen in a Holstein-Friesian steer

Epidermoid cysts were identified in the rumen of a 2-year-old Holstein-Friesian steer. Small nodules (<4 mm diameter) filled with paste-like, friable, white material were scattered in the rumen wall. Microscopically, the nodules were located in the submucosal connective tissue and comprised of cysts lined by stratified squamous epithelium surrounding keratin debris, exhibiting features identical to those of epidermoid cysts. The cysts were surrounded by chronic inflammation. The ruminal mucosa contained vesicles or cystic cavities filled by inflammatory exudate, in addition to empty cystic spaces lined by flattened endothelial cells, which were possibly of lymphatic origin. The development of these epidermoid cysts might have resulted from implantation of exfoliated squamous epithelial cells from damaged ruminal epithelium into the submucosal connective tissue, although the precise aetiology of this anomaly remains to be defined.