Dermoid sinus and bone defects of the fifth thoracic vertebrae in a shih‐tzu

Abstract

LETTERSDermoid sinus and bone defects of the fifth thoracic vertebrae in a shih-tzu MADAMRecently, we encountered a five year old, neutered, male shihtzu presented with an acute onset of ataxia of the pelvic limbs after a tuft of hair, protruding from a dermoid sinus on the dorsal midline of the cranial thoracic region, had been pulled by the groomer. Radiographs showed a defect of the spinous process and the vertebral bodyof T5. The spinous process was found to be separated into two sections forming an opening on the dorsal aspect of the vertebral body. Myelography showed that the dermoid sinus was tethered to the spinal cord, classified as a type IV dermoid sinus. A dorsal approach was performed to remove the dermoid sinus. The sinus was found to exist between a bone defect of the spinous process and the vertebral body of T5. A dorsal laminectomy was also performed at the level of T5. One month postoperatively, the dog was still mildly ataxic with subtle conscious propioceptive deficits in the pelvic limbs. At a telephone interview two months later, the owners reported great improvement in the dog, and no noticeable ataxia.There are many reports in Rhodesian ridgebacks (Mann & Stratton 1996) but a dermoid sinus has been reported only once previously in a shih-tzu (Selcer and others 1984). Reports have shown that neurological signs with dermoid sinuses are most often caused by infection of the sinus with dissemination to the spinal cord or brain (that is, myelitis, encephalitis). We report this case to encourage clinicians to consider this type of trauma to the spinal cord when assessing an animal with a dermoid sinus and neurological signs. Clinicians should educate their clients in exercising caution with pets with a dermoid sinus.

Dermoid sinus and spina bifida in three dogs and a cat

“…In rare cases, a dermoid sinus can be associated with vertebral malformations, as in these cases presented here (Selcer and others 1984, Fatone and others 1995, Cornegliani and others 2001, Bowens and others 2005, Colon and others 2007, Tong and Simpson 2009). Spina bifida seems to be related to dermoid sinuses that reach the spinal canal (Fatone and others 1995, Pratt and others 2000, Bowens and others 2005, Colon and others 2007, Tong and Simpson 2009). This may be due to the interaction between neural crest, mesoderm (the embryological origin of the bone tissue) and the neuroectodermal neural tube that is required for normal development of the neuraxis.…”

“…Dermoid sinuses can, however, be asymptomatic for months to years before becoming infected or inflamed (Selcer and others 1984, Marks and others 1993, Lambrechts 1996, Pratt and others 2000, Davies and others 2004) or can cause spinal cord compression due to debris accumulation (Fatone and others 1995) or cyst enlargement (Tong and Simpson 2009). Neurological abnormalities can also occur acutely because of trauma caused by pulling the protruding hair from the sinus in asymptomatic animals (Colon and others 2007). These facts support the idea of preventive surgery at least in cases where the defects extend to the spinal canal.…”

“…In the cases where dermoid sinuses were related to neurological deficits and surgery performed (in 8 of 11 cases), surgery resulted in seven of eight cases at least some improvement or complete resolution of signs. The follow‐up time varied from two weeks to four years (Lord and others 1957, Selcer and others 1984, Gammie 1986, Fatone and others 1995, Lambrechts 1996, Pratt and others 2000, Bowens and others 2005, Colon and others 2007, Tong and Simpson 2009). Based on the results presented here, the authors recommend surgical treatment for dermoid sinuses reaching the spinal canal.…”

Spinal dermoid sinus in a Dachshund with vertebral and thoracic limb malformations

“…Their characteristic cutaneous ridge in this breed is an autosomal dominant mutation of fibroblast growth factor genes that predispose the animals to dermoid sinus [39,40]. This developmental abnormality has been reported in several other breeds, including the American Cocker Spaniel, English Cocker Spaniel, English Springer Spaniel, Boxer, Chow-Chow, Golden Retriever, Shih Tzu, Siberian Husky, Yorkshire Terrier, German Shepherd, Rottweiler, Boerboel, Great Pyrenees, Swedish Vallhund, Chinese Crested, Victorian Bulldog, and occasionally in domestic cats [6-8,11-14,16,17,41-46]. No reports of dermoid sinus in Dachshunds were found in the literature.…”

Multiple dermoid sinuses of type Vb and IIIb on the head of a Saint Bernard dog

“…Isolated cases of DS have also been reported in other breeds (Table 1) [9-40], without evidence of a genetic predisposition [34,51]. Several authors have reported that DSes are found most frequently in the cervical and thoracic regions [11,14,38] with possible extension to the meninges and subarachnoid space [9,21,23,32,33,35-37,39,40]. They are less frequently found in the sacral region [38].…”