Localized gingival overgrowths – differential diagnosis for dental practitioners

Case 1

A 23-year-old female presented to the AIMST Dental Institute with an asymptomatic, pale-pink, firm, sessile mass arising from the maxillary labial gingiva of tooth UL2 (Figure 1). Clinically, the lesion measured 1 x 0.6 x 0.4 cm approximately, with no surface ulceration or signs of inflammation. The mass had been present for two years, with the patient's only complaint being its unaesthetic appearance. Her medical history was non-contributory. The patient could not relate any traumatic event to the area and, except for plaque accumulation on the surface of teeth, there was no evidence of other local irritating factors. A periapical radiograph revealed no obvious pathology, ruling out a central lesion. Based on the clinical findings, a provisional diagnosis of fibrous epulis was made. However, other benign neoplasms were also considered in the differential diagnosis. The lesion was excised from the underlying mucosa, preserving the gingival architecture and contour (Figure 2). The final diagnosis after histopathological evaluation was irritational fibroma. Hence, a wider excision of the area was not indicated and the patient remained free of recurrence during a follow-up period of more than 6 months (Figure 3).

Case 2

A 53-year-old female was referred for evaluation of a reddish pink growth on the maxillary right posterior buccal gingiva. The mass measured about 0.7 x 0.5 x 0.5 cm, was soft in consistency and showed no evidence of surface ulceration (Figure 4). Her medical and family histories were non-contributory. A periapical radiograph of the region revealed superficial erosion of the alveolar crest and loss of cortication on the distal aspect of tooth UR5 (Figure 5). The differential diagnosis included pyogenic granuloma and peripheral giant cell granuloma. A final pathologic diagnosis after excisional biopsy was peripheral giant cell granuloma.

Case 3

A 49-year-old male was referred for evaluation of a pale pink mass on the mandibular right posterior buccal gingiva. The lesion measured approximately 1.5 x 1 x 0.6 cm, and was bony-hard in consistency (Figure 6). The clinical impression from the referring clinician was a bony overgrowth. The mass was excised as a requisite for pre-prosthetic preparation and submitted for histopathologic evaluation. The lesion was diagnosed as a fibro-epithelial polyp with dystrophic calcification.

Hyperplastic lesions/reactive lesions

All hyperplastic lesions are reactive or inflammatory in nature and represent an exuberant tissue response to persistent irritation or trauma.5 They are the most common oral exophytic lesions, described with distinct clinical terms based on the anatomical site of involvement, clinical features, or microscopic picture.11 Different entities of reactive hyperplasias arise from the gingival connective tissue response to varied intensities or sources of irritation. Hence, such a cause should be investigated by the practitioner during routine clinical examination.

Fibrous epulis is by far the most frequently reported reactive lesion on the gingiva, which usually presents with features as described in Case 1. These lesions represent a reactive fibrous hyperplasia (irritational/traumatic fibroma) or a fibro-epithelial hyperplasia (fibro-epithelial polyp) of the gingiva.12^,13^,14^,15

Certain studies have reported pyogenic granuloma as the most common reactive lesion on the gingiva. This vascular lesion is usually painless and appears as a small, red, exophytic mass with a tendency to bleed easily.16^,17 Some cases may show surface ulceration and can exhibit rapid growth that simulates malignancy, while long-standing lesions appear pink due to secondary fibrosis.13

A peripheral giant cell epulis clinically resembles the gingival pyogenic granuloma,11^,13 as reported in Case 2. They are unique to the gingival mucosa with a tendency to resorb the underlying alveolar bone.18

Concentrations of circulating hormones also have an important role in the development of some of these lesions. Cases of peripheral giant cell epulides associated with hyperparathyroidism and reactive lesions occurring during puberty have been reported in the past. Frequently, pyogenic granulomas can develop in the second or third trimesters of pregnancy and ‘pregnancy tumour’ is a term often used to describe this lesion. Elevated female sex hormones during pregnancy cause the gingival tissues to respond in an exaggerated manner to local factors, resulting in this lesion, which often regresses after parturition.14^,19^,20^,21

Recently, the occurrence of pyogenic granuloma and giant cell epulis have been related to dental implants.22

This category of reactive lesions also includes the peripheral ossifying fibroma, which occurs more often in the maxillary anterior gingivae. Clinically, it appears as a pink or red, exophytic lesion, usually less than 2 cm in diameter. Further, most studies have reported female predilection and peak incidences in the first and second decades of life.12^,13^,23

Epulis fissuratum or denture-induced hyperplasia is a reactive lesion associated with ill-fitting dentures. Arising usually in the vestibule, or sometimes beneath the denture base, they are asymptomatic overgrowths, varying from pink and firm to erythematous and oedematous with occasional ulceration.24

Inflammatory lesions

Abscesses related to teeth (both periodontal and periapical) can appear as ovoid elevations on the gingiva, along the lateral aspect of tooth roots. Pain, sensitivity to percussion, tooth elevation in the socket, increased mobility and suppuration are common findings in such cases. On occasions, in periapical abscesses, pus may accumulate beneath the mucosa where a ‘gum boil’ forms before a sinus develops. Further, a nodule of granulation tissue (parulis) often arises at the sinus opening in response to mucosal irritation by pus.25

In a previously healthy site, a gingival abscess can manifest as an acute suppurative swelling following impaction of a foreign body (food substance, toothbrush, toothpick, etc) into the gingiva.26 Inflammatory, oedematous focal gingival enlargement may occur as a result of localized gingivitis and pericoronitis.27^,28

Peripheral odontogenic tumours

Peripheral odontogenic tumours are uncommon benign focal overgrowths of the oral soft tissue, occurring in the gingiva and overlying jaw mucosa. These peripheral tumours demonstrate histologic characteristics of their intra-osseous counterpart and many times are initially diagnosed clinically as reactive or inflammatory lesions. In a review of publications in English from 1987 to 1999, Manor et al29 found 129 reported cases of peripheral odontogenic tumours, with peripheral odontogenic fibroma as the most frequently described entity, followed by the other odontogenic tumours listed in Table 1. Further evidence from recent studies also demonstrated similar frequencies in the occurrence of these tumours.30^,31

Benign tumours

The majority of the soft tissue tumours occurring in other sites of the body can present in the oral mucosa as well. Tumours on the gingiva can be clinically indistinguishable from focal fibrous hyperplasias.14 Common connective tissue tumours, like true fibromas, cannot reliably be distinguished from reactive lesions.5

An uncommon tumour, oral focal mucinosis, has been reviewed by Aldred et al.32 Their study showed that this tumour occurred most commonly on the gingiva, and often presented clinically as an innocuous soft tissue swelling. Gabay et al33 reported one case on the gingiva causing adjacent cervical root resorption.

Another rare tumour causing a verrucous or papillary excrescence predominantly on the gingiva and alveolar ridge is verruciform xanthoma. This lesion represents an unusual reaction to localized epithelial trauma or degeneration. Cases of verruciform xanthoma have been associated with lichen planus, lupus erythematosus, pemphigus vulgaris, leukoplakia and carcinoma in situ.34^,35

Sometimes, traumatic neuromas can occur in the oral cavity following nerve injury, more often in the region of the metal nerve. A small nodule near the mental foramen, which causes considerable pain on pressure, is typical of a traumatic neuroma arising from a severed mental nerve. They arise as a disorganized mass, from proliferation of the proximal end of a severed nerve in an attempt to re-establish innervation with the distal segment.13^,36^,37

Malignant tumours

As a group, primary gingival malignancies are rare; the overall incidence of gingival carcinoma is less than 10% of all carcinomas arising on the oral mucosa, although it has been increasingly reported at this site in the past few years.38 The most frequently reported neoplasm on the gingiva is squamous cell carcinoma; however, cases of primary gingival verrucous carcinomas and rare malignant mesenchymal lesions on gingiva have also been published. The aetiology for malignancies in general is considered to be multifactorial, however, it has been estimated that smoking and alcohol consumption account for 75% of all cases of oral cancer. Carcinomas on the gingiva in particular may present with benign features and sometimes similarity to reactive lesions or periodontal disease may lead to delays in diagnosis or even to misdiagnosis, thereby posing problems in management.39^,40 The proximity of underlying periosteum and alveolar bone usually invites early invasion, thereby resulting in radiographic evidence of bone involvement. Superficial erosion may arise apparently as a pressure phenomenon.40^,41

Verrucous carcinomas, with a characteristic white warty appearance, may involve the gingiva and alveolar ridge. Seen commonly in elderly men, particularly associated with the habit of tobacco chewing, this tumour is described to be slow growing, locally aggressive with a low propensity for regional or distant metastasis.42

A potentially aggressive tumour of melanocytic origin is the malignant melanoma. Primary oral melanomas account for fewer than 1% of all melanomas. This neoplasm is more common in Japan and Africa than in Western countries; occurring more often in older adults with a predilection for the hard palate and maxillary alveolar gingiva. Most patients exhibit pre-existing oral pigmentation before the onset of this malignancy. Hence, a classic clinical presentation of an irregular, variegated, pigmented lesion on the oral mucosa necessitates suspicion of a melanoma. However, 4% to 15% of oral melanomas are non-pigmented, a feature that can delay early recognition and diagnosis.10^,43^,44^,45

Critically, Kaposi's sarcoma is a malignancy commonly associated with HIV infection. Frequently arising on the palate and gingiva, this malignant connective tissue tumour usually presents as purplish nodules with a tendency to bleed.46

Malignant lymphoproliferative disorders, like non-Hodgkin's lymphoma, arise primarily within the lymph nodes, and involve the Waldeyer's ring, usually in the head and neck region. However, extranodal locations have been seen in the past and cases of gingival lymphomas have also been reported. Clinically, they appear as non-tender swellings, often mimicking an inflammatory process.47^,48 Given an appropriate clinical setting, an extranodal lymphoma must be considered in the differential diagnosis.

Metastasis to the jawbones and oral soft tissues accounts only for about 1% of all oral malignancies. Nevertheless, when oral soft tissue metastases do occur, gingiva (54%) is the most commonly affected site. Suggested pathogenesis for the metastatic process, inflammation normally occurring in the gingiva, plays a role in the attraction of metastatic cells towards this site. Lung carcinoma is the most frequently reported malignancy that metastasizes to the gingiva, which occurs significantly in older males. Other tumours with oral metastasis include malignancies of the breast, kidney, bone and colon. Metastases to oral soft tissues develop as rapidly growing expansile masses which tend to ulcerate, bleed and cause pain. In addition, most lesions show associated bony changes on radiographs. However, early lesions of gingival metastasis may resemble hyperplastic or reactive lesions.2^,7^,8^,49

Cysts

Occasionally, jaw cysts can produce circumscribed, fluctuant swellings on the gingiva. In adults, gingival cysts which arise from the proliferation of dental lamina rests, and sometimes lateral periodontal cysts, may produce conspicuous focal gingival swellings. Gingival cysts are frequently described as the extra-osseous counterparts of the intra-osseous lateral periodontal cysts. With a predilection for the mandibular canine-premolar region, these cysts may produce swellings usually less than 1 cm in diameter.50^,51

Inflammatory cysts, such as the paradental cysts, mandibular infected buccal cysts and lateral radicular cysts may also produce swellings confined to the gingiva. Paradental cysts result from inflammation around the crowns of erupting teeth, particularly mandibular third molars. They usually present on the buccal or distobuccal aspects of teeth. A similar variety encountered in younger individuals is the mandibular infected buccal cyst which typically affects the mandibular first or second molar teeth. The associated teeth in the above types of cysts are usually vital, which allows differentiation from a radicular cyst on the lateral aspect of tooth roots.51

Dayan et al52 described a peripheral type of odontogenic keratocyst that occurred entirely within the gingiva and had clinical features similar to gingival cysts. Unlike the central variety, they are non-aggressive, usually without recurrence after complete surgical removal.

Systemic diseases

Many systemic disorders present with oral manifestations, of which some occur on the gingiva more frequently. Chloroma or granulocytic sarcoma is an extramedullary myeloid tumour, which is a solid collection of leukaemic cells occurring outside the bone marrow. They are mostly associated with acute myeloid leukaemia.53 Lynch et al54 described a case of granulocytic sarcoma on the gingiva which gave a clinical impression of a pyogenic granuloma.

Strawberry gingivitis, a red oedematous enlargement with petechiae, is a rare manifestation of Wegener's granulomatosis, but characteristic of this granulomatous disease. Initially, this condition may be localized and patches of affected gingiva may coalesce to produce a generalized pattern involving the attached gingiva, which may extend even beyond the mucogingival junction. However, oral lesions appear in only 5–10% of patients affected with this disorder.55^,56

Erythematous hyperplastic gingiva may also be seen in cases of Crohn's disease.57

Benign epithelial lesions

Pigmented naevi, known as ‘common mole’ on the skin, are a rare finding in the oral mucosa. These brown or black pigmented lesions may be flat or slightly raised and are seen more often on the palate, but gingiva is not an uncommon location. The clinical appearance is not diagnostic, so a biopsy is usually required to exclude other pigmented lesions and, most importantly, an early malignant melanoma.58 Like naevi, verruca vulgaris, the ‘common wart’, is infrequent in the oral mucosa, but children are more often affected as a result of autoinoculation from warts on their fingers. Clinically, they are white, sessile and exophytic with finger-like projections. Though the majority of them are found on the lips and palate, 10–20% occur on the gingiva.14^,59

Bony overgrowths

Localized overgrowths of bone are called exostoses. Most dentists are familiar with these bony protuberances arising from the alveolar bone, frequently distinct on the maxillary buccal and mandibular lingual aspects (torus mandibularis).25^,60 However, on occasions, soft tissue hyperplasias and peripheral tumours with calcifications can mimic bony overgrowths, as in Case 3.