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Lower Lip Bump (Mucocele verus Mucus Retention Cyst) Minor Salivary Gland Traumatic Lesion with Histopathology

see also: Complication From Lip Biopsy for Sjogrens with Mucocele Formation (Granulation Tissue)Plunging Ranula Transoral Resection (Sublingual Gland) Aided With Sialendoscopy with HistopathologyTherapeutic Agents for Oral Mucosal Disease Treatment Strategies

Pemphigus vulgaris of the larynx, pharynx, and oral cavityBechet's Syndrome (Neuro-Beçhet) Rythmic Myoclonus Laryngeal - Pharyngeal

protocol by Eyas Alzayadneh, Chris Jensen, and Henry Hoffman (initiated Feb 2023)


Confusing terminology (mucocele vs mucus retention cyst) - 'extravasation versus retention':

  • Mucocele: lesion resulting from the rupture of a duct of the salivary gland with extravasation ('spillage') of mucus into the surrounding connective tissue without an epithelial lining (Chi 2010)
    • Mucoceles represent a "mucus excape reaction" and "mucus extravasation phenomenon" (Miranda 2022)
  • Mucus retention cyst (also known as "sialocyst" or "mucus duct cyst" are cysts lined by salivary ductal epithelium (Chi 2010)
    • Mucus retention cysts develop from mucus buildup behind blocked glandular ducts - more commonly in cheek (buccal) or palate areas (Bowers 2021)



  • Lower lip mucoceles are frequently asymptomatic but can be attended by interference with chewing, eating, and speech as well as altering cosmetic appearance (Bowers 2021).


  • Barros et al through a 10 year retrospective review ending 2016,  587 lip lesions (of which 76% occurred on the lower lip) -  identified in a single institution in Brazil  were identified - with mucocele being the most common diagnosis (25% of cases) (Barros 2020) 


  • mucoceles rare in upper lip with Chi et al contemplating that the cause for this discrepancy is due to a greater number and density of salivary glands in lower lip - combined with greater force applied to the lower lip along with "parafunctional habits" such as lip biting (Chi 2010)
  • 'constant trauma' to the lower lip was implicated by Barros et al as a cause for the frequent occurrence of mucoceles (Barros 2020)
  • 'damage to minor salivary glands or ducts' (Bowers 2021)

Histopathology: mucus extravasation ('spillage') with and associated inflamed granulation tissue response - without an true cystic epithelial lining

  • variants reported: mucoceles with myxoglobulosis ('collagenous spherulosis'); mucoceles with papillary synovial metaplasia-like change

Differential Diagnosis of Lower Lip Lesions:

  • mucocele, traumatic fibroma (tissue tag); papilloma; pyogenic granluoma; hemangioma, varix (vascular lesion); nonspecific inflammation/irritation; lichen planus; lymphangioma; nevus; neoplasm; vsiculobullous condition (Chi 2010) 
  • reactive/inflammatory lesions (including mucocele) (43.4%); infectious lesions (2.7%), benign neoplasms (5.6%), malignant neoplasms (3.6%), oral potential malignant disorders (33.1%), other (11.6%)  in a study by Barros et al (2020)

Management of lower lip mucoceles

  • observation without intervention; surgical excision with removal of minor salivary gland; marsupialization; 'micromarsupialization" (Delbem 2000), CO2 laser ablation, cryotherapy, intralesional steroid injection (reported to have high rates of recurrence by Bowers and Schaitkin 2021), sclerosing agents
  • potential complications from surgical treatment reported: lip disfigurement, damage to adjacent minor salivary gland ducts ('recurrence'), lip numbness and scarring

Case Example: Clinical Course and Histopathology


22 year old healthy man who developed painless swelling in the left lower lip without recollection of any instigating features .

The lip lesion enlarged over a few days and has been stable since – bothering him occasionally by striking it when chewing or biting. It has never drained or been drained.  

Modified Operative Note:

Procedure: Resection of left lower lip lesion 1-1/2 cm x 1 cm

Preop Diagnosis: Left lower lip lesion possible mucocele versus traumatic fibroma

Postop Diagnosis: Left lower lip mucocele (confirmation by path pending)

Anesthesia: 2% lidocaine with 1-100,000 epinephrine injected to the left lower lip to a volume of 1-1/2 cc

Description of Procedure: Following identification the patient informed consent and a brief timeout as well as the above-mentioned anesthesia the region was prepped and draped in a sterile fashion using Betadine swabs and the lip was put on stretch with retraction having placed images from previous photography from the clinic showing the location of the left lower lip mass prior to injection to corroborate with the findings at the time of injection allowing for a fusiform incision 1-1/2 x 1 cm made parallel to the vermilion to encompass the mass on the wet portion of the left lower lip. Dissection was carried deeper down to muscle as an inflamed minor salivary gland was identified filling the space between mucosa and underlying muscle was identified. An adjacent more normal appearing second salivary gland removed along with the enlarged gland. Closure was effected by way of 6 separate 5-0 Vicryl sutures the first 3 of which incorporated underlying muscle to obliterate dead space.


Left lower lip lesion: Extravasated mucin with associated fibrosis and histiocytic inflammation consistent with mucocele.   


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