The Veterinary Journal the Veterinary Journal 175 (2008) 379–383
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Available online at www.sciencedirect.com The Veterinary Journal The Veterinary Journal 175 (2008) 379–383 www.elsevier.com/locate/tvjl The buccal lymph node (lymphonodus buccalis) in dogs: Occurrence, anatomical location, histological characteristics and clinical implications Christophe R. Casteleyn a,*, Maartje van der Steen a, Jan Declercq b, Paul Simoens a a Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium b Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium Accepted 28 January 2007 Abstract Three dogs were presented for clinical examination with bilateral buccal nodules which were identified as enlarged buccal lymph nodes. As little is known about this pathology, 150 dogs were examined by anatomical dissection for the presence of buccal lymph nodes. They were found in 13 dogs, occurring bilaterally in six dogs and unilaterally in seven dogs. Two buccal lymph nodes were bilobulated and one was double. The lymph nodes were always located dorsal to the zygomatic muscle and rostral to the masseter muscle in the region where the superior labial vein drains into the facial vein. Histology demonstrated a large amount of intranodal adipose tissue scattered throughout the lymphoid tissue. The canine buccal lymph node should not be confused with the accessory parotid or ventral buccal salivary gland and is clinically important as it can enlarge due to tumour metastasis or inflammation of the buccal region. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Anatomy; Buccal nodule; Dog; Histology; Lymphatic system 1. Introduction skin biopsy specimens revealed cutaneous non-epitheliotro- pic lymphoma. A 7-month-old Afghan hound, a 3.5-month-old New- The anatomical features and possible pathology of buc- foundland pup and an 8-year-old Shar pei were presented cal lymph nodes are poorly documented. Rumph et al. for evaluation of bilateral nodular lesions in the buccal (1980) described a clinical case of a 4-month-old male Lab- region (Figs. 1a, 1b and 1c). The nodules, which were not rador Retriever presented with masses rostroventral to painful in any of the dogs, ranged from 1 to 2 cm in diam- each eye. The masses were periodically swollen, but seemed eter and were diagnosed as enlarged buccal lymph nodes. not to induce any disease. Based on this clinical case, the In the Afghan Hound, clinical examination revealed no authors systematically looked for similar masses and found other abnormalities and the buccal lymph nodes spontane- them in 15/171 examined Greyhounds. After histology, ously regressed. The Newfoundland pup had a subcutane- they concluded that the masses were lymph nodes which ous abscess in the right upper lip. The Shar pei suffered they named the facial lymph node. Shelton and Forsythe from generalized peripheral lymphadenopathy and subse- (1979) performed a similar study and found the lymph quently showed nodular lesions in the ears, the anal region node, which they called the buccal lymph node (lymphono- and the perivulvar fold. Histopathological examination of dus buccalis), in 22/250 dogs of various breeds, ages and sex. Both the studies of Shelton and Forsythe (1979) and * Corresponding author. Tel.: +32 9 264 77 15; fax: +32 9 264 77 90. Rumph et al. (1980) have been briefly reviewed by Evans E-mail address: [email protected] (C.R. Casteleyn). (1993). Adams (1986) illustrated in a textbook drawing 1090-0233/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2007.01.019 380 C.R. Casteleyn et al. / The Veterinary Journal 175 (2008) 379–383 in the literature and because of its possible clinical implica- tions, a screening was performed to determine its prevalence, exact anatomical location and histological characteristics. 2. Materials and methods The buccal regions of 150 dogs of various breeds, age and sex, euthanased for reasons other than this study, were examined macro- scopically (Table 1). Photographs of each presumed buccal lymph node were taken using a digital camera (Canon EOS 300D) and samples for histological analysis were fixed in 3.5% buffered formaldehyde for 1 week followed by paraffin wax embedding using a histokinette (Shandon Citadel 1000, Thermo Electron). Tissue sections (8 lm thick) were made, mounted on slides, stained with haematoxylin (Hematoxylin C.I. 75290, Merck) and Fig. 1a. Bilateral enlargement of buccal lymph nodes (arrows) in an eosin (Eosine yellow C.I. 45380, VWR International) and examined with a Afghan hound due to unknown aetiology. motorized microscope (Olympus BX 61) linked to a digital camera (Olympus DP 50). Table 1 Occurrence of the buccal lymph node in 150 dogs of various breeds Breed Number Unilateral Bilateral of dogs presence of presence of examined buccal buccal lymph node lymph node American Staffordshire Terrier 10 0 0 Basset Hound 1 0 0 Beagle 2 0 0 Belgian Malinois 5 0 0 Belgian Tervuren 1 0 0 Berner Sennen 4 1 0 Boerboel 1 0 0 Fig. 1b. A 4-month-old Newfoundland pup with enlarged buccal lymph Border Collie 1 0 0 nodes caused by abscessation of the right upper lip (arrow). Bouvier des Flandres 3 1 0 Boxer 2 0 0 Bull Terrier 1 0 0 Collie 1 0 0 Dalmatian 1 0 0 Doberman Pincher 4 1 1 Dogue de Bordeaux 2 0 0 English Bulldog 1 0 0 Flat Coated Retriever 1 0 0 German Pointer 1 0 0 German Shepherd Dog 12 2 1 Giant Schnauzer 1 0 0 Golden Retriever 6 0 3 Great Dane 2 0 0 Groenendaler 1 0 0 Irish Setter 1 0 0 Jack Russell Terrier 9 0 0 Keeshond 1 0 0 Labrador Retriever 12 2 0 Fig. 1c. Bilaterally enlarged buccal lymph nodes (arrows) in a Shar pei Maltese 1 0 0 suffering from a cutaneous non-epitheliotropic lymphoma. Mongrel 41 0 0 Napolitan Mastiff 2 0 0 an anonymous but apparently similar lymph node located Newfoundland 3 0 0 Pekingese 1 0 0 rostral to the angle of confluence of the facial and the supe- Rottweiler 9 0 0 rior labial veins. Saint Bernard 1 0 0 The buccal lymph node has been described in various Shar pei 2 0 1 other species including humans, primates, rabbits, guinea Siberian Husky 1 0 0 pigs, rats and camels (Barone et al., 1950; Spira, 1962; Standard Poodle 1 0 0 Weimaraner 1 0 0 Grasse´, 1972; Grau, 1974; Barone, 1996). Since the pres- ence of the canine buccal lymph node is rarely documented Total 150 7 6 C.R. Casteleyn et al. / The Veterinary Journal 175 (2008) 379–383 381 For reference, samples were also taken from the mandibular and parotid lymph nodes and from the parotid, accessory parotid and ventral buccal salivary glands. 3. Results 3.1. Prevalence and macroscopic characteristics In 2/150 examined dogs, the buccal lymph nodes were enlarged causing a swelling which could be palpated through the skin. After dissection, the buccal lymph nodes were found in 13 dogs (i.e. 9% of all examined dogs). The lymph nodes were bilaterally present in six dogs and unilat- erally in seven dogs, more specifically four times on the left Fig. 3. Bilobulated buccal lymph node (arrows) located medial to the side and three times on the right side of the head (Table 1). superior labial vein. Notice the position of the buccal lymph node at the Two out of the total number of 19 observed buccal lymph level of the fourth premolar (P4) in the right upper jaw of a German nodes were bilobulated and one was double. Shepherd Dog. The lymph nodes were always located dorsal to the zygomatic muscle and rostral to the masseter muscle in the region where the superior labial vein drains into the facial vein (Fig. 2). The buccal lymph node was located ros- tral to the facial vein in seven cases: once dorsal to the superior labial vein in the angle of confluence of the facial and superior labial veins, once medial to the superior labial vein (Fig. 3), four times directly ventral to the angle of con- fluence of the facial and superior labial veins (Fig. 4a), and once more caudal to the angle of confluence. In one case the lymph node was located medial to the facial vein where the superior labial vein joined the facial vein. In the other 11 cases, the lymph node was located caudodorsal to the facial vein: four times directly caudal to the angle of conflu- ence of the facial and superior labial veins, and seven times ventral and distinctly caudal to the angle of confluence Fig. 4a. Drawing of the canine head showing a buccal lymph node located (Fig. 2). The distance between the angle of confluence directly ventral to the angle of confluence of the facial and superior labial and the buccal lymph node varied from 2 to 10 mm. The veins. Some landmarks of the buccal area are additionally represented: ln. variable position of the observed canine buccal lymph buccalis (1), lnn. mandibulares (2), ln. parotideus (3), gl. parotis (4), gl. nodes is illustrated in Fig. 4b. parotis accessoria (5), gl. mandibularis (6), m. zygomaticus (7), m. masseter The size of the buccal lymph nodes was variable with the (8), m. buccinator (9), m. orbicularis oris (10), v. jugularis externa (11), v. maxillaris (12), v. facialis (13), v. labialis inferior (14), v. labialis superior long rostrocaudal axis ranging from 5 to 24 mm, the short (15), v. lateralis nasi (16). dorsoventral axis from 3 to 14 mm, and the thickness from 1 to 5 mm. Fig. 2. Localisation of the buccal lymph node (arrow) in a Doberman Fig.