Blisters on the vermilion border of the lip

Mucosal pathology

Dr. Emmanuelle Bourrat

Saint-Louis Hospital

The clinical case
Now it's your turn!
Co-prescription and advice

Clinical case presentation

An otherwise healthy 18-month-old infant has had these asymptomatic lesions on the lower lip since the age of 3 months. The lesions fluctuate in number and prominence but never disappear completely.

There is no triggering factor, whether traumatic or food-related, and the rest of the oral mucosa is completely normal. These are small, tense blisters with cloudy or clear contents, ranging in size from 1 to 10 mm.

During meals, the blisters, which are superficial and fragile, rupture, releasing a viscous fluid without leaving any underlying erosion.

Your turn

What is your diagnosis?

Select 1 answer(s) from the following choices:

Hereditary epidermolysis bullosa

Autoimmune bullous dermatosis

Multiple superficial mucoceles

Herpes recurrences

Wrong answer!

Good answer!

Diagnosis selected

The elementary lesion (fluid swelling) and its contents (saliva) support the diagnosis of multiple superficial mucoceles.

Oral mucoceles, or mucoid pseudocysts, are benign conditions affecting the accessory salivary glands of the oral mucosa.

There are two etiological types:

Mucocele due to extravasation, caused by a rupture of the gland epithelium, often post-traumatic in children, causes saliva to flow into the juxtaglandular mucosa, forming a pseudocyst.
Retention mucoceles are caused by blockage of saliva flow due to stenosis or epithelial proliferation of the excretory duct, resulting in a true salivary cyst that is often deeper and more solid. Multiple superficial mucoceles of the lip are rare in children, are of the extravasation type, and may be promoted by sucking.

Explanation of incorrect answers

Hereditary epidermolysis bullosa and autoimmune bullous dermatoses with mucosal involvement often involve oral lesions, but these are always followed by painful erosions.
Strict intraoral herpes recurrences are rare but do occur. They occur in flare-ups interspersed with complete remissions and are also painful.

Treatment

No treatment was given to this child. Since he is only slightly or not at all bothered, it can be assumed that once feeding with a bottle stops, the condition will disappear.

Expert's message

While a single post-traumatic mucocele of the lip is well known in children, there are also multiple superficial forms whose pathophysiology remains poorly understood.

References:

^{Abe A, Kurita K, Hayashi H, Minagawa M. Multiple mucoceles of the lower lip: A case report. Clin Case Rep. 2019;7:1388–1390.}