Curious case of submandibular swelling

Abstract

A 35-year-old woman presented with a progressively increasing swelling over the left side of the upper part of the neck for the past 8 months with no associated pain over the swelling. On examination, a non-tender, firm, well-defined, oval swelling of size 3×2 cm was palpable in the left submandibular region that was mobile, non-pulsatile and free from the overlying skin and the underlying muscle. Ultrasonography revealed a bilobed heteroechoic lesion in the left submandibular region with internal vascularity and multiple macrocalcification within it. During the procedure for surgically excising the swelling, we found that it was separate from the gland and vascular structures, had a sinus tracking over and around the left submandibular gland extending beyond the angle of mandible up to the root of a decayed left lower second molar tooth.

Background

The submandibular triangle is a clinically important area in the head and neck region. Isolated submandibular mass is a common lesion that patients can present with in the surgery department. The differential diagnosis of a submandibular mass includes salivary gland pathology, lymph node disease, soft tissue tumours, vascular and neuronal pathologies.¹ Infections and granulomatous diseases can also give rise to a mass in the submandibular triangle.² Dental pathology is the most common aetiology causing infections of the oral cavity especially in developing countries.³ The position of the dental roots in relation to the anatomy of the head and neck can predict the location that infection is most likely to spread.^{4 5} Infection of second and third mandibular molars reaches the submandibular region because the apex of the dental root extends below the mylohyoid line for these teeth.⁶ Even though a frequent association with a mandibular tooth has been documented in 80%–87% of the reported cases, dental pain of the involved teeth has been observed in only 50% of the patients. Further, the draining sinus tracking at a location distal from the origin of infection presents a dilemma during diagnosis.⁷ However, an excisional biopsy is the mainstay of treatment in a submandibular triangle mass.² This case report demonstrates the need for a thorough workup to rule out dental infections in a patient presenting with swelling or a sinus tract in the submandibular region.

Case presentation

A 35-year-old woman came to the general surgery department with complaints of swelling over the left side of the upper part of the neck for the past 8 months. She noted a progressive increase in the size of the swelling over these months. There was no associated pain over the swelling. There was no history of dental caries. There was no history of an increase in the size of swelling during food intake, fever, halitosis, breathing difficulty, dysphasia or voice change. There was no history of weight loss. There was no history of any similar swelling. There was no history of tuberculosis. The patient was not habituated to smoking or alcohol. Family history was not significant.

Clinical examination revealed a single swelling of size 3×2 cm in the left submandibular region, 1 cm from the midline and 1 cm below the mandible. The skin over the swelling had minimal redness and scaling. Two external openings were noted with no active discharge. The swelling did not move with deglutition or protrusion of the tongue. On palpation, there was no local rise of temperature. The swelling was firm in consistency, mobile, non-pulsatile and not fixed to the overlying skin or underlying muscle. No other swellings or cervical lymph nodes were palpable. On bimanual palpation, no calculi or discharge was noted. Examination of the oral cavity was normal. Minimal halitosis was present. Differential diagnosis at this time was left submandibular sialadenitis, lymph nodal lesion and abscess.

Investigations

Routine investigations done for work up of anaesthetic fitness were found to be within normal limits.

1. Ultrasound of the neck reported an heteroechoeic bilobed lesion in the left submandibular region measuring 1×1.3×2 cm (APxTRxCC). Multiple macrocalcifications were seen within the lesion. There was internal vascularity within the lesion. Few subcentimetric benign-appearing lymph nodes with preserved fatty hilum noted were noted in the level Ib and II lymph node stations on both sides of the neck. Differential diagnosis of submandibular lymphadenitis or abscess was considered. Submandibular salivary gland not seen separately.

2. Fine needle aspiration cytology of the swelling was suggestive of a suppurative lesion.

3. Histopathology of the excised specimen was reported as an acute on the chronic inflammatory lesion. A sinus tract was identified in the specimen.

Treatment

The patient was planned for excision of swelling/left submandibular sialadenectomy. Preoperative prophylactic intravenous antibiotic was given. Written consent for the proposed surgery was obtained. An elliptical incision was made around the two sinus openings. A swelling was found in the left submandibular region extending 2 cm from the midline and a fingerbreadth from the mandible. The swelling was dissected from the underlying muscle. The swelling was found to have a sinus tract which was tracking over and around the left submandibular gland but was separate from the gland and vascular structures. Dissection was continued up to the point where it reached the angle of the mandible (figure 1). Further dissection could not be carried out. Hence, a clip was placed at the angle of the mandible and an intraoperative CT scan was taken. CT scan showed sinus extending up to the root of the left lower second molar tooth (figure 2). Further dissection was continued up to the root of the decayed tooth. The dental opinion was sought on the table. As this differential diagnosis was not contemplated, a consent for tooth extraction had not been taken. An immediate tooth extraction could not be done. The patient was advised tooth extraction after 2 weeks. The sinus tract was removed in total and sent for histopathological examination.

Figure 1.

Excision in progress, sinus extending behind the mandible.

Figure 2.

Intraoperative CT scan showing clip placed and sinus extending up to the root of the left lower second molar tooth.

Outcome and follow-up

The patient tolerated the procedure well. Suture removal was done after 1 week. The histopathological report of the specimen was acute-on-chronic inflammation. After suture removal, the patient was advised to attend the dental clinic for tooth extraction which was done after 2 weeks. At a follow-up after 18 months, the patient was symptom-free.

Discussion

Submandibular triangle swelling can arise from infections and granulomatous diseases.² Non-neoplastic lesions may resemble neoplastic lesions both clinically and pathologically. Therefore, differentiation between these two is of utmost importance in the management of a submandibular triangle mass.⁸

The most common cause of infections in the head and neck region is of dental origin and the most common site of swelling is the submandibular space.⁹ Odontogenic infections can spread via three methods: haematogenous dissemination, lymphogenous dissemination and/or direct extension into fascial spaces.⁴ One of the rare presentations of dental caries is a cutaneous sinus tract.^10–13

Dental caries may result in infection of the pulp. This pulp infection may result in an abscess that may erode the mandible and pass along the periosteum or fascial planes to another site. For the molar teeth, this kind of an abscess may reach the submandibular space and present as either a recurrent sinus or sometimes a swelling.^{14 15} The molar tooth being relatively inaccessible to the examination may be missed as the source of infection causing swelling or sinus in the submandibular space. Sometimes dental caries may not be overtly visible or cause symptoms.

Tooth extraction or treatment of dental caries will eliminate the source of infection and is the mainstay in the treatment of odontogenic cutaneous sinus tracts. Surgical excision of the lesion without appropriate treatment of the infected teeth will inevitably lead to recurrence.¹⁶ Hence, in patients presenting with recurrent sinuses in the submandibular region, awareness of the problem and correction of the source result in a cure without the patient having to undergo surgical excision of the sinus or swelling. Nevertheless, the necessity of surgical excision has been recommended by a few studies.¹⁷

Patient’s perspective.

I noticed the swelling in the left side of the face when I came for a whole body check-up in May 2017. I was evaluated in General Surgery department and given a 3 week course of antibiotic. It subsided initially but after sometime started increasing in size and my relatives started enquiring about it. When the swelling started increasing in size I was further evaluated with ultrasound and tested for TB. I was told that I have a submandibular gland swelling. Tuberculosis test was reported negative and the doctor suggested surgery to remove the swelling. In February when I underwent surgery I was told that the swelling was due to caries teeth. The tooth was removed subsequently. My problem resolved. I came and met my doctor later to thank him for the needful.

Learning points.

• To consider dental aetiology in patients presenting with a non-neoplastic submandibular triangle mass.

• Removal of the primary dental focus of infection for limitation of the spread of the infection.

• Surgical excision of the sinus tract is required for the complete cure of the lesion.