A 1-day-old American Paint Horse was presented for a large air-filled mass along the ventral aspect of the neck. Bronchoscopy and oesophagoscopy revealed no sign of communication with the trachea or oesophagus. Radiographs and a computed tomography scan of the neck identified a communicating tract between the lumen of the cystic mass and mid-trachea. The foal was systemically healthy at this initial presentation, and delayed removal of the cyst was recommended to allow further maturation of the foal prior to undergoing general anaesthesia. Upon discharge, the cyst continued to grow in size and became more fluid than air-filled requiring repeat centesis and draining. The foal was then re-presented at 3 weeks of age for surgical removal. In surgery, direct communication with the trachea was identified and ligated. Histopathology demonstrated that the cyst lining was composed of squamous epithelium with goblet cells and occasional ciliated cells. The location, morphological features and congenital presentation of the mass were consistent with a paratracheal air cyst (PAC). Surgical resection resulted in excellent functional and cosmetic outcome. Although not previously reported in horses, PAC should be included in the differential diagnosis of an air-filled ventral neck mass in equine neonates. Complete surgical excision may result in a successful outcome.

中文翻译：

---

小马驹气管旁空气囊肿

一头 1 天大的 American Paint Horse 出现在颈部腹侧的大型充气团块中。支气管镜检查和食管镜检查未发现与气管或食管相通的迹象。颈部 X 线片和计算机断层扫描确定囊性肿块的管腔和气管中部之间有一条交通通道。小马驹在初次就诊时全身健康，建议延迟切除囊肿，以便在进行全身麻醉之前让小马驹进一步成熟。出院后，囊肿继续变大，变得比充满空气的液体更多，需要重复穿刺和引流。然后，小马驹在 3 周大时再次出现以进行手术切除。在手术中，与气管的直接通信被识别并结扎。组织病理学表明，囊肿内层由鳞状上皮组成，带有杯状细胞和偶尔的纤毛细胞。肿块的位置、形态特征和先天性表现与气管旁空气囊肿（PAC）一致。手术切除导致出色的功能和美容效果。虽然以前没有在马中报道过，但 PAC 应包括在马新生儿腹侧颈部充气肿块的鉴别诊断中。完整的手术切除可能会导致成功的结果。虽然以前没有在马中报道过，但 PAC 应包括在马新生儿腹侧颈部充气肿块的鉴别诊断中。完整的手术切除可能会导致成功的结果。虽然以前没有在马中报道过，但 PAC 应包括在马新生儿腹侧颈部充气肿块的鉴别诊断中。完整的手术切除可能会导致成功的结果。