Malignant Ulcer of the mouth – What you need to know - Dr. Muammar Abu-Serriah

Article by: Dr. Muammar Abu-Serriah
BDS (Hons), MBChB, FDSRCPS (Glasg), MRCS (Glasg), FRCSGlasg (OMFS), MSc(MedSci) (Hons), MSc (Hons), PhD

Dr. Muammar Abu-Serriah, Oral, Maxillofacial Head & Neck Surgeon explains the signs and symptoms of mouth ulcers and when it is necessary to refer.

There are several causes of mouth ulcers which are listed in Table 1. The vast majority of mouth ulcers are not cancerous.  Compared to other cancers, oral cancer is uncommon but it often presents as an ulcer. Cancer of the oral cavity and its treatment has a significant impact on a patient’s swallowing, eating, speech, appearance, self-image, social functioning and quality of life.  Although uncommon, there is a disproportionate focus on oral cancer due to this impact.  The vast majority of patients with head and neck cancer present in a state of advanced disease.  We know that early detection of oral cancer  leads to less invasive treatment, better cure rates and hence, a better quality of life. 

With careful systematic examination of the oral cavity under good light, it is possible to detect an early cancerous ulcer.   

Red flag signs of a cancerous ulcer of the oral cavity

There are clinical red flag signs that may assist the clinician in distinguishing an ulcer due to cancer. These are summarised in Table 1.

Fig 1: Rolled up, indurated ulcer with necrotic and
slough base of the right lateral tongue consistent with
squamous cell carcinoma (SCC) of the tongue.

Fig 2: Ulcerated area of the upper gingiva in a
patient complaint of progressive mobility of maxillary
incisors. Biopsy confirmed squamous cell carcinoma
(SCC) of the anterior maxillary gingiva

Table 1: Red flag signs of a mouth ulcer 

Sign/ symptoms



It is very unlikely that a cancerous ulcer would be bilateral


Multiple ulcers are unlikely to be cancerous


Cancerous ulcers are often painless


Any ulcer that persists for 3 weeks or more needs urgent referral to a maxillofacial or head and neck specialist with an interest in oral cancer


Common with cancer of the tongue or oropharynx

Contact bleeding

Gentle digital palpation of the lesion causes bleeding

Necrotic base

The lesion looks like a pot hole or punched out

Rolled up edges

The edges are heaped up like the crater of a volcano (Fig 1)


Do not only look but also feel. Cancerous ulcer has very firm/ hard surrounding tissue

Altered sensation

E.g. numbness of the tongue (cancer of tongue) or numbness of lower lip (cancer of the gum of the bottom jaw)

Restricted movement

Hypoglossal nerve palsy in tongue cancer – late sign (Fig 2)

Neck lump

This is a late sign, but always palpate the neck for any cervical lymphoadenopathy

Obstructive salivary gland symptoms

If the submandibular salivary gland duct is involved in cancer of floor of the mouth for example, this can result in meal time painful swelling of the gland.

Non healing tooth socket

If a tooth socket fails to heal within 3 weeks following tooth extraction then refer patient urgently

New nexplained mobility of teeth

If a group of teeth are becoming mobile (or loose), while the remaining teeth are firm and healthy - this is suspicious and needs further investigation

Changed speech

Due to tethering of tongue

Increasing size

Often > 5 mm and it becomes progressively bigger