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 Table of Contents  
Year : 2016  |  Volume : 28  |  Issue : 1  |  Page : 48-51

Intramucosal nevus as a lesion on the lip: A case report

Department of Oral Medicine and Radiology, AECS Maaruti College of Dental Sciences and Research Centre, Bengaluru, Karnataka, India

Date of Web Publication8-Sep-2016

Correspondence Address:
Janani Nagarajan
#1/37, White House, 3rd Cross, Assayee Road, Opposite Bengalee Association, Near Ulsoor Lake, Bengaluru – 560 042, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0972-1363.189983

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Oral melanocytic nevi are benign proliferation of nevus cells in the epithelial layer, the submucosal layer, or both. They are classified as junctional, intramucosal, and compound nevi. They may also be classified as congenital or acquired. Unlike their cutaneous counterparts, oral melanocytic nevi are rare. Intramucosal nevi are typically light brown and dome-shaped, and are the most common type, accounting for 64% of all reported oral nevi. The common blue nevus is the second most common type found in the oral cavity, accounting for 16.5–36% of all oral nevi. In this article, we report a case of an intramucosal nevus in a male patient on the right corner of the lower lip, which presented as a mucocele and was histopathologically confirmed.

Keywords: Intramucosal nevus, lower lip, mucocele, oral melanocytic nevi

How to cite this article:
Nagarajan J, Raghuram S, Bandalore SR, Patil S. Intramucosal nevus as a lesion on the lip: A case report. J Indian Acad Oral Med Radiol 2016;28:48-51

How to cite this URL:
Nagarajan J, Raghuram S, Bandalore SR, Patil S. Intramucosal nevus as a lesion on the lip: A case report. J Indian Acad Oral Med Radiol [serial online] 2016 [cited 2022 Dec 7];28:48-51. Available from: http://www.jiaomr.in/text.asp?2016/28/1/48/189983

   Introduction Top

Oral melanocytic nevi are benign proliferations of nevus cells in the epithelial layer, submucosal layer, or both, and are derived from the neural crest.[1] These cells migrate to the skin and oral mucous membranes during embryogenesis. Nevus cell formation begins with the proliferation of melanocytes along the basal cell layer. They retain melanin pigment and form nests of theques.[1] Most oral nevi are solitary and asymptomatic. Congenital melanocytic nevi are present at birth or appear shortly after. Acquired melanocytic nevi begin to appear in early childhood. The lesions are usually detected as an incidental finding on routine dental examination.[1] Clinically, most oral nevi are benign and present as asymptomatic, well-circumscribed, round or oval macules or papules with smooth surface that range in color from light brown to black.[2] Their incidence is 0.1–1.15% in the United States.[3] Lesions may be underreported because they often go undetected. No case of melanoma arising in or around an oral melanocytic nevus has been described. Oral nevi may occur in persons of all races and are reported more frequently in White patients (55%) than in Black patients (23%). Oral mucosal nevi have a slight female predominance (1.5:1 female-to-male ratio).[4] The average age at diagnosis is 35 years. They are best categorized as hamartomas rather than true neoplasms.

   Case History Top

A male patient aged 38 years presented to our department with a chief complaint of decay in the lower left back tooth region and a brownish discoloration and swelling on the right corner of the lower lip. On eliciting history of the presenting illness, the patient gave a history of decay in the lower left back tooth region since 1 year and food lodgement in the same region since few months. The patient complained of a swelling on the right corner of the lower labial mucosa since the age of 5 years, which had not increased or decreased in size since then; patient had no pain or discomfort associated with the swelling, and wanted to remove it for aesthetic reasons. Patient also gave a history of its solitary and asymptomatic nature. There was no other significant medical history. Patient had a habit of smoking 2 cigarettes' per day since 2 years and had quit smoking since 1 year.

On intraoral examination, moderate stains and calculus deposits were present, attrition with respect to the lower anterior teeth, dental caries with respect to 38, that was nontender on vestibular palpation, and percussion and an edentulous space with respect to 37. On examination of the extraoral swelling, a distinct well-defined solitary oval/round brownish-blue mucosal swelling was seen on the right corner of the lower labial mucosa, measuring approximately 1 × 1.5 cm, extending from the right commissure of the mouth up to 1.5 cm below on the lower labial mucosa. Margins were well-defined, surface appeared smooth and shiny, and the surrounding area appeared normal. On palpation, the swelling was well-circumscribed with a smooth surface, was nontender, soft in consistency, and fluctuant. Other soft tissue findings included the gingiva that was pink with physiological brownish black pigmentation and bleeding on probing with a coated tongue [Figure 1].
Figure 1: Clinical picture showing intramucosal nevus as a lesion on the right corner of the lower lip that presented as a mucocele

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On the basis of history and clinical features, we arrived at a provisional diagnosis of mucocele with chronic generalized gingivitis. A differential diagnosis of melanotic macule, melanoacanthoma, mucosal melanoma, amalgam tattoo, hemangioma, Kaposi sarcoma, varix, vascular malformation, smokers melanosis, physiological pigmentation, and post-inflammatory hyper/hypopigmentation was considered. An excisional biopsy was performed under local anesthesia with 2% lidocaine as local infiltration. The capsule was removed as a whole and was sent for histopathological examination. The biopsied site was sutured and patient was administered antibiotics and analgesics for 5 days.

Histopathological report


One soft tissue specimen which was brown in color, soft in consistency, and with irregular surface texture measuring 0.9 × 0.8 × 0.7 cm was stored in 10% formalin. The entire specimen was taken for processing.


Microscopic examination of the hematoxylin and eosin stained soft tissue specimen showed overlying orthokeratinized stratified squamous epithelium and an underlying connective tissue component. The connective tissue was loose and edematous and showed mild chronic inflammatory infiltrate predominantly composed of lymphocytes. Few endothelial lined blood vessels were also seen. Deeper portion of the connective tissue showed lesional component with small ovoid cells. The cells had small and uniform nuclei and moderate amounts of eosinophilic cytoplasm with indistinct cell boundaries suggestive of nevus cells. The cells in the superficial aspect of the lesion demonstrated melanin [Figure 2]a and [Figure 2]b. The clinical and histopathological features were suggestive of intramucosal nevus. The biopsy site showed uneventful healing [Figure 3].
Figure 2: (a) Histopathological picture showing clusters of nevus cells in the deeper connective tissue. Resolution: 10× magnification; (b) Histopathological picture showing theques of nevus cells showing melanin pigment. Resolution: 40× magnification

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Figure 3: Post-biopsy picture

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   Discussion Top

Oral nevi are benign proliferation of nevus cells, and usually present as asymptomatic, well-circumscribed, round or oval macules or papules with a smooth surface that range in color from light brown to black. Intramucosal nevi may be nonpigmented or amelanotic 15–22% of the time and present as sessile growths that resemble fibromas or papillomas.[4] Intraoral nevus was first reported by Field and Ackermann,[5] the term intralamina propria nevus was first proposed by comerford.[6] Later king et al.[7] adopted the term intramucosal nevus. In this case, the lesion was seen not only on the right corner of the lower lip but also gave an impression of a mucocele. Oral nevi may be mistaken for other pigmented lesions in the oral cavity secondary to endogenous and exogenous causes. Certain clinical features can assist clinicians in making the correct diagnosis. Melanotic macules and amalgam tattoos are usually flat and 80% of the nevi are elevated. Ethnic pigmentation is nearly always symmetric and rarely affects the surface topography or disturbs the normal stippling in the gingival. Smoker's melanosis involves only the anterior gingiva, and, of course, a history of smoking is essential. Vascular lesions usually blanch with compression and melanocytic proliferations do not. Malignant melanoma is frequently associated with diffuse areas of pigmentation, possible ulceration, nodularity, variegation of color, and an irregular outline. The histopathological report also showed that the case was an intramucosal nevus.

Congenital nevi penetrate the connective tissue layer in a diffuse sheet-like pattern and tend to “split” into collagen bundles.[3] Acquired melanocytic nevi begin to appear in early childhood. Intramucosal nevi and rarely spitz nevi may be nonpigmented or amelanotic 15–22% of the time and present as sessile growths that resemble fibromas or papillomas.[3] The average size of an oral nevus is 0.3–0.5 cm at the largest diameter. Blue nevi are smaller than intramucosal nevi. The lesion in our case measured approximately 1 × 1.5 cm. Biopsy and histologic examinations of all pigmented and nonpigmented oral lesions are indicated to confirm the nature of the lesion. The primary diagnostic procedure is excisional biopsy. All melanocytic and amelanocytic lesions in the oral cavity must be viewed with suspicion. Complete excision is suggested to be the most reliable approach to oral melanocytic lesions. Reports have shown that the prognosis of oral melanocytic nevi is excellent.

   Conclusion Top

Although intramucosal nevi occur as brown or bluish macules, unusual presentation of these lesions is possible. A systematic and careful diagnostic approach should be used when confronting pigmented lesions in the oral cavity, where vascular, exogenous and endogenous sources of pigmentation should be considered when formulating a differential diagnosis. Indeed, nonpigmented or exophytic nevi have occasionally been reported in the international literature. However, a biopsy to identify the correct nature of these lesions is always recommended.


We thank the teaching staff of the Department of Oral and Maxillofacial Pathology, AECS Maaruti College of Dental Sciences and Research Centre, Bangalore.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Cohen Y, Goldenberg-Cohen N, Akrish S, Shani T, Amariglio N, Dratviman- Storobinsky O, et al. BRAF and GNAQ mutations in melanocytic tumors of the oral cavity. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:778-84.  Back to cited text no. 1
Grichnik JM, Rodhes AR, Sober AJ. Benign hyperplasias and neoplasias of melanocytes. In: Lever's Histopathology of the skin. 7th ed. Philadelphia: Lippincott Williams & Wilkins; 2005. p. 889.  Back to cited text no. 2
Buchner A, Hansen LS. Pigmented nevi of the oral mucosa. A clinicopathologic study of 36 new cases and review of 155 cases from the literature. Part II: Analysis of 191 cases. Oral Surg Oral Med Oral Pathol 1987;63:676-82.  Back to cited text no. 3
Buchner A, Leider AS, Merell PW, Carpenter WM. Melanocytic nevi of the oral mucosa: A clinicopathologic study of 130 cases from northern California. J Oral Pathol Med 1990;19:197:201.  Back to cited text no. 4
Field HJ, Ackerman AA. Non-pigmented nevus on labial mucosa. Am J Orthodontics Oral Surg 1943;29:180-1.  Back to cited text no. 5
Wijs RW, Meleti M, Bloemena E, Van der Waal I. A non pigmented nevus as an uncommon gingival swelling. Ned Tijdschr Tandheelkd 2012;119:283-4.  Back to cited text no. 6
King OH Jr, Blankenship JP, King WA, Coleman SA. The frequency of pigmented nevi in the oral cavity. Report of five cases. Oral Surg Oral Med Oral Pathol 1967;23:82-90.  Back to cited text no. 7


  [Figure 1], [Figure 2], [Figure 3]


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