SummaryThe dentigerous cyst or temporal teratoma in horses is a well‐known congenital malformation that occurs in the temporal region and usually contains dental tissue. This case report describes two horses with a previously unreported variant of the dentigerous cyst associated with an exostosis arising from the temporal bone. The principal clinical sign was a draining tract opening at the margin of the right pinna in both horses. There was no evidence of an ectopic tooth on the radiographs or at ultrasonographic examination. Computed tomography combined with positive contrast sinography of the draining tract revealed bone formation arising from the supramastoid crest of the right temporal bone extending towards a cyst‐like structure but without direct connection in both cases. This bone formation was located at a site on the supramastoid crest, close to the external acoustic meatus, where ectopic teeth may also occur. Both cysts were removed surgically with a good long‐term outcome.

SummaryThis report describes the successful treatment of a traumatic splenic abscess by transabdominal drainage under ultrasonographic guidance. The gelding presented for investigation of recurrent pyrexia, mild abdominal pain and weight loss after a penetrating trauma to the caudolateral abdomen 5 weeks previously. At this stage, the abdominal wall had healed and a splenic abscess was diagnosed. Before treatment, mature adhesions between the abdominal wall and the spleen were confirmed by diagnostic laparoscopy in the standing horse. Transabdominal ultrasound‐guided drainage was performed, followed by intralesional placement of a balloon catheter for 2 weeks and a silicone drain for an additional week. Postoperatively, the horse was treated with intralesional and systemic antibiotics. The healing process was unremarkable and the horse was discharged 4 weeks postoperatively. At 10 months post‐surgery, after the body condition score had normalised, the horse returned to its previous level of performance.

Background: Horses may acquire a range of paranasal sinus diseases. Clinical studies show slight differences regarding anatomical regions and age. Histopathological examination of tissue samples could play an important role in the diagnostic process. Therefore, detailed knowledge of the histological appearance of the paranasal sinus mucosa (PSM) and the nasomaxillary aperture mucosa (NAM) is essential. The objective of this study was to determine topographic and age-related differences within the healthy equine PSM. In addition, we aimed to gain detailed knowledge of the histological appearance of the NAM in comparison to the PSM. Results: The PSM had an average height of 75.72 ± 44.48 μm with a two-row pseudostratified columnar epithelium of 13.52 ± 4.78 μm. The parameters mucosal height, epithelial height and number of goblet cells revealed significant dependency of the sample site and age group. The maxillary and dorsal conchal sinus showed the highest values for these parameters. In terms of age, younger horses showed a significantly higher total mucosal height in contrast to a significantly lower epithelial height than older horses. Positive correlation was seen between the epithelial height and number of goblet cells. The NAM had an average height of 820.27 ± 653.21 μm. Its pseudostratified epithelium was usually arranged in three rows and had an average height of 44.9 ± 12.78 μm. The number of goblet cells in the NAM was five times higher than in the PSM. Serous glands were found in only 4% of the PSM samples and 100% of the NAM samples. Conclusions: There are significant histological differences between different paranasal sinus sites and between different groups of age. This may be related to an altered susceptibility for certain pathologies. The striking difference in the histological appearance of the NAM compared to the PSM could be due to an enhanced role in mucociliary clearance. Further studies are necessary to improve the understanding of mucosal function in specific paranasal sinus compartments and mucosal changes generated by different diseases.

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