Inheritance of dermoid sinus in the Rhodesian ridgeback

OBJECTIVES: TO define the mode of inheritance of dermoid sinus. METHODS: A chi-squared analysis was performed on data from 46 litters produced between 1990 and 2001. Data were corrected to avoid bias in the segregation ratio. RESULTS: In data from 57 litters (n=492), 82 dermoid sinus positive offspring were observed. The frequency of affected offspring in the Swedish Rhodesian ridgeback population is estimated to be between 8 and 10 per cent. CLINICAL SIGNIFICANCE: Bias in heredity pattern may be caused by undetected dermoid sinus type V. Improved clinical diagnosis of all dermoid sinus types is therefore crucial.     

True dermoid cyst in a Rhodesian ridgeback

A case of a true dermoid cyst in a Rhodesian ridgeback is described. The mass was located in the dorsal cervical midline at the level of the first cervical vertebra, and was resected surgically. In contrast to other types of dermoid sinus described in the literature, the mass did not have a tract connecting it to, nor an opening on to, the surface of the skin. A diagnosis of true dermoid cyst was made.     

Autosomal dominant mutation causing the dorsal ridge predisposes for dermoid sinus in Rhodesian ridgeback dogs

OBJECTIVES: To define the mode of inheritance of the dorsal ridge and investigate if the ridge predisposes to the congenital abnormality dermoid sinus in the Rhodesian ridgeback. METHODS: Segregation analysis was performed, including 87 litters (n=803) produced in Sweden between 1981 and 2002. Data were corrected to avoid bias in the segregation ratio. Chi-squared analysis was performed including 402 litters (n=3598) for the evaluation of a possible genetic correlation between the ridge and dermoid sinus. RESULTS: The ridge is inherited in an autosomal dominant mode and predisposes for dermoid sinus. The frequency of ridgeless offspring in the Swedish Rhodesian ridgeback population is estimated to be 5.6 per cent. CLINICAL SIGNIFICANCE: Rhodesian ridgeback dogs that carry the ridge trait are predisposed to dermoid sinus.     

Dermoid Sinus in the Rhodesian Ridgeback

Abstract—The Rhodesian Ridgeback is a modern breed having been standardized in 1922. It originated in South Africa by crossing Hottentot dogs with various European breeds. The breed has one defect, a congenital malformation, generally known as dermoid sinus. The authors have investigated the inheritance of the condition and, contrary to the hypotheses of others, suggest that it is a simple recessive character. The implications of this are discussed.
Réslamé—Le chien de Rhodesie, dénommé Ridgeback, est d'un élevage récent, bien établi depuis 1922. II est originaire d'Afrique du Sud, résultant d'un croisement de chiens Hottentots et de divers chiens européens. Cette souche a un défaut, une malformation congénitale généralement désignée kyste dermoide. Les auteurs ont recherchés l'hérédité de cette condition, et contrairement à d'autres hypothèses, ils suggèrent qu'il s'agit d'un caractère héréditaire récessif. Les conséquences en sont discutées.
Zusammenfassung—Der Rhodesische "Ridgeback' ist eine neuzeitliche Zucht, die im Jahre 1922 standardisiert wurde. Ihr Ursprung ist in Sued Afrika, vollzogen durch Kreuzung von Hottentotten Hunden mit verschiedenen europaeischen Rassen. Der "Ridgeback' hat einen Fehler: eine congeni-tale Missbildung, die allgemein als "Dermoid Sinus' bekannt ist.
Die Autoren haben die Vererbung dieses Zustandes untersucht und schlagen vor, entgegen den Hypothesen anderer Autoren, sie als ein einfaches, recessives Merkmal zu bezeichnen.
Die sich daraus ergebenden Beziehungen werden eroertert.     

Dermoid sinus in a golden retriever

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.     

Dermoid sinus and spinal malformations in a Yorkshire terrier: Diagnosis and follow-up

An unusual case of a Yorkshire terrier with a dermoid sinus associated with multiple spinal/costal malformations is described. The dog presented with ataxia and pain in the dorsal thoracic region. Diagnostic characterisation of the lesions was obtained with radiography, myelography and computed tomography. After surgical removal of the sinus, the dog showed marked clinical improvement over a two-year period.     

Dermoid sinus at the lumbosacral junction in an English springer spaniel

A dermoid sinus was identified in a springer spaniel that presented with hindlimb neurological deficits. The sinus was continuous with the dura mater at the level of the lumbosacral junction. The presence of hair and debris adjacent to neural tissue had elicited a myelitis. A dorsal laminectomy was required to allow complete surgical resection of the sinus. The dog's neurological status improved after treatment and this improvement was maintained over a five-month follow-up period.     

Trachyonychia associated with alopecia areata in a Rhodesian Ridgeback

Trachyonychia associated with alopecia areata was diagnosed in an 8-year-old Rhodesian Ridgeback. Clinical and histological findings are described in this respectively unreported and rare condition in the dog.     

Dermoid cyst in the tongue of a dog

A German Shepherd Dog presented with recurrent intermandibular and intralingual swelling. Cytological and microbiological findings on fluid aspirated from the mass were consistent with an infected cyst lined by epithelium. The sinus was explored and an epithelium-lined cystic structure was extirpated from the frenulum and body of the tongue. This structure was diagnosed histologically as a dermoid cyst.     

Behavioural Studies on Some Rhodesian Rodents

Field studies (Lake Kariba shoreline and Salisbury) and experiments with a captive colony of 12 species of Rhodesian rodents were undertaken for a period of three years. Comparative behavioural data are presented here with special reference to den and nest behaviour, group and territorial behaviour, reproductive and juvenile behaviour, and activity pattern. No species was found to be truly gregarious except Dendromus mesomelas, but Praomys (Mastomys) natalensis, Lemniscomys griselda, Tatera leucogaster, and Aethomys chrysophilus were found to tolerate crowded conditions in captivity. Nipple dragging of young was found in both species of Aethomys and in Acomys, with the remainder observed to utilise mouth carrying behaviour. It was noted that especially in Rhabdomys and Praomys (Mastomysj, and also in Lemniscomys, young have a strong tendency to scatter in all directions from a disturbed nest, even before their eyes open. The significance of nipple dragging, scattering and crowding behaviour and correlation to survival and tendency to irrupt are discussed. All species were found to be nocturnal (usually with irregular sub cycles of activity) except Rhabdomys (largely diurnal), Lemniscomys (diurnal/crepuscular) and Otomys (nocturnal/crepuscular).     

Dermoid cyst of the spinal cord associated with ataxia in a cat

A young adult Balinese cat developed complete hindlimb paralysis which persisted for six weeks. Clinical findings suggested a lesion compressing the spinal cord and this was confirmed at necropsy. A dermoid cyst was present at the level of the third thoracic vertebra. The cyst was lined by stratified squamous epithelium and contained desquamated keratinised material and hair fragments. Sebaceous glands and hair follicles were present in the connective tissue wall. This is the first report of a dermoid cyst in the spinal cord of a cat. The lesion is considered to be a congenital anomaly.     

Aspects of the Expressive Behaviour of the Waterhuck Kobus Ellipsiprymnus Ellipsiprymnus in a Rhodesian Game Park

Aspects of the expressive behaviour of waterbuck K.e. ellipsiprymnus are described and the results of this study support the contention that K.e. ellipsiprymnus and K.e. defassa are conspecifics. Comparisons with observations on water buck behaviour recorded by other authors show a number of differences as well as similarities in behavior patterns.     

Bilateral sinus cysts in a filly treated by endoscopic sinus surgery

Bilateral cysts in the frontal and caudal maxillary sinuses in a filly treated by endoscopic sinus surgery (sinoscopy) and triangulation technique are described. Sinoscopy has the advantage of being a minimally invasive technique and permits a complete inspection of the frontal and maxillary sinuses, which is not possible through flap sinusotomy.