Abstract
The authors present five cases of calibre-persistent labial artery (CPLA) all of which were diagnosed clinically as a labial mucocoele. The purpose of this article is to bring this rarely reported lesion to the attention of clinicians.
A calibre-persistent labial artery (CPLA) has been defined as a primary arterial branch that penetrates into the submucosal tissue of the lip without division or loss of calibre and presents as a palpable mass in the lip . The reason why the artery maintains it dimensions without reducing in diameter is not understood. CPLA was first described by H owell & F reedman in 1973 and was called ‘prominent inferior labial artery’. The current terminology was introduced by M iko et al. in 1980. This phenomenon was discovered in the gastrointestinal tract in 1962 , where it may cause fatal gastric haemorrhage . CPLA was thought to be a rare vascular anomaly, but according to L ovas et al. it is relatively common, although often unrecognized and infrequently reported.
Clinical and histological diagnostic criteria for CPLA have been described by L ovas et al. and M iko et al. . Clinically, CPLA appears as an elevated lesion on the upper or lower labial mucosa that is visibly pulsatile in a lateral direction . Histologically, a CPLA should have a diameter:depth ratio or quotient of less than 1.6, where the diameter of the artery is measured from the junction of the media and external elastic lamina and the depth is the distance from the epithelial/connective tissue junction to the most superficial junction of the vessel media and external elastic lamina . L ovas et al. used a simpler criterion which was a large-diameter artery immediately subjacent the surface epithelium.
The main arterial supply of the upper lip is from the superior labial artery (SLA, mean external diameter, 1.8 mm [SD, 0.74 mm]); in addition, the subalar and septal branches contribute to its vascularisation . According to P inar & B ilger the SLA runs tortuously and anastomoses with the opposite artery in the middle of the upper lip. Anastomoses formed by the artery are either in the vermilion or between the mucosa and the orbicularis oris muscle . The main arterial supply to the lower lip is derived from three branches of the facial artery, the inferior labial artery (ILA) (mean external diameter, 1.4 mm [SD, 0.31 mm]) and the horizontal and vertical labiomental arteries . The ILA, after separating from the facial artery, immediately enters the lower lip and runs between the mucosa and the muscle . There are different arterial distributions in the lower lip, such as end-to-end anastomoses between bilateral ILA and the ILA anastomosing with the submental artery .
Case report 1
An 82-year-old Caucasian male was referred for a swelling on his left lower lip which he bit occasionally, exacerbating the swelling. There was no history of bleeding from the lesion. He had smoked 20 cigarettes per day for over 40 years but had stopped smoking tobacco 15 years ago. He had ischaemic heart disease, recurrent vertigo, non-insulin dependent diabetes mellitus, prostatism, diverticulosis, cataracts and had had a nodular basal cell carcinoma on his right temporal region excised 3 years previously.
On examination, there was a slightly raised linear lesion on the mucosa of the left side of the lower lip ( Fig. 1 ). It was soft, non-tender, had a slightly blue colour and was fluid-filled. No pulsation was noted and the clinical presentation was suggestive of a mucocoele. The rest of his oral mucosa was normal. Excisional biopsy by an oral and maxillofacial surgeon was done under local analgesia on the same day. During the operation, just after the lesion was excised, profuse and pulsating bleeding was observed. A large labial artery was detected and successfully ligated with a suture. Haemostasis was achieved before the patient left the clinic. He came for a review appointment 1 week later and reported no postoperative complications. The biopsy site was almost healed but a very strong pulsation was felt. A month later, he was reviewed again. The lower lip was completely asymptomatic and no pulsation was felt in the region.
Histopathological examination showed that the surface of the specimen was covered by intact normal stratified squamous epithelium. Taking up much of the submucosa was a large artery with marked intimal thickening and focal atheromatous plaques ( Fig. 2 ). Foamy macrophages and small zones of calcification were present within the fibrous plaques. The internal elastic lamina (IEL) was disrupted in one region and the media was thinned in this area. Adjacent to the artery was normal fibrous connective tissue with fat and small vessels and nerves.
Case report 2
This patient was a 35-year-old male referred to an oral and maxillofacial surgeon for management of a swelling on his right lower lip. The excised lesion was sent for histopathological examination. The lesion had been present as an unhealed ulcer for about 6 months. There were no intra-operative complications during the excisional biopsy. Histologically, there was a thick walled artery in the superficial connective tissue. The artery was partially occluded by an atherosclerotic plaque ( Fig. 3 ). Similar to Case 1, the IEL and the media were disrupted in places. The surface epithelium was ulcerated, presumably due to low-grade mechanical trauma such as lip-biting.
Case report 2
This patient was a 35-year-old male referred to an oral and maxillofacial surgeon for management of a swelling on his right lower lip. The excised lesion was sent for histopathological examination. The lesion had been present as an unhealed ulcer for about 6 months. There were no intra-operative complications during the excisional biopsy. Histologically, there was a thick walled artery in the superficial connective tissue. The artery was partially occluded by an atherosclerotic plaque ( Fig. 3 ). Similar to Case 1, the IEL and the media were disrupted in places. The surface epithelium was ulcerated, presumably due to low-grade mechanical trauma such as lip-biting.
