Salivary mucocele in a wild cat

An adult, female jaguarundi cat (Herpaylurus yaguarondi), weighing 4.8 kg, was referred to the Veterinary Hospital because of a cervical mucocele that had been present for approximately 2 y. The cause had not been established. Conservative treatment with periodic drainage had been administered 5 times, but the mucocele returned with intervals varying from 1 to 6 mo.

Physical examination revealed a fluctuant swelling located in the right submandibular region (Figure 1).

Figure 1. Animal prepared for surgical procedure. Observe the fluctuant swelling located in the right submandibular region.

The treatment determined was the resection of the mandibular-sublingual gland complex. After premedication with midazolam (0.2 mg/kg body weight [BW], IM), ketamine (10 mg/kg BW, IM), and butorphanol (0.2 mg/kg BW, IM), anesthesia was induced and maintained with isoflurane.

The animal was positioned in left lateral recumbency. By digital occlusion of the external jugular vein, the right maxillary and linguofacial veins were identified. A skin incision was made over the mandibular salivary gland, between these veins. After the platysma muscle had been penetrated, the fibrous capsule of the mandibular salivary gland was incised, and the gland separated from the capsule by using blunt dissection. Bleeding vessels to the gland were ligatured. The dissection was continued until the rupture in the sublingual gland has been located (Figure 2). The digastric muscle was retracted and the caudal part of the sublingual gland resected after ligating its duct. The capsule edges and subcutaneous tissue were apposed by using a continuous suture; and the skin was closed with interrupted sutures.

Figure 2. Mandibular gland separated from the capsule and dissection continued until the rupture in the sublingual gland has been observed.

The salivary mucocele was not drained by ventral incision, because during the dissection of the glands, the mucocele was inadvertently penetrated and all the contents were evacuated. Enrofloxacin was administered (5 mg/kg BW, IM, q24h) for 5d after the surgery. No complication was observed in the postoperative period. In the last evaluation, 11 mo after the surgery, the cat did not present any recurrence of the process.

A salivary mucocele is an accumulation of saliva in a single or multilocuted cavity lined with connective tissue, contiguous to a salivary gland or duct (1,2). In general, it is the sublingual gland that is involved; less frequently, the parotid and zygomatic glands (1). The most common places in which mucoceles associated with the sublingual gland develop are the cervical, sublingual, and pharyngeal areas (1,3).

A cervical salivary mucocele occurs when the saliva collects in the subcutaneous tissues of the cervical or intermandibular area; it is rarely observed in felines (3,4). A sialocele is associated with duct or gland tearing, as observed in this case (2,3,4). The lesion has been associated with trauma, seeds, and a foreign body, but, most commonly, the inciting cause is not known (1). Since the cranial part of the sublingual gland is polystomatic, while the caudal portion is monostomatic, the leakage may occur in various sites of the cervical region (1).

The diagnosis is made by palpation and aspiration of the swelling. In general, the palpation is painless, except in the acute period or if infected (1,3). The fluid obtained is thick and golden colored, since there is no associated inflammation (2). It may be blood stained because of the tissue reaction or the paracentesis (1). If necessary, the diagnosis can be confirmed by using a mucus-specific stain such as periodic acid-Schiff (2,3). Abscess, tumor, and branchial cleft cysts must be differentiated from a salivary mucocele (3,5,6). Although histological examination was not made in this case, the diagnosis was based on the history, clinical signs, localization of the rupture, and postoperative evolution.

Some cases have been resolved by using periodic drainage, but surgical treatment is necessary to prevent recurrence (3), as observed in this case. The injury is frequently associated with the sublingual gland; however, the mandibular gland is then removed due to the close apposition of both glands (2,3). In this case, because the affected side was easily detected by physical examination, procedures such as sialography and detection of the tunnel or tracts by incision of the mucocele were not necessary (1,3).CVJ