Gingival squamous cell carcinoma masquerading as an aphthous ulcer.

Gingival squamous cell carcinoma (GSCC) is an uncommon condition of the oral cavity. It is seldom associated with classic risk factors of oral cancer and shows a predilection for females. It's close clinical resemblances to various lesions of the oral cavity may make it go unnoticed. This may lead to diagnosis at advanced stages and coupled with the proximity to underlying alveolar bone may result in subsequent morbidity and mortality. A case of GSCC camouflaged as an aphthous ulcer in a middle aged woman is presented. The article highlights the importance of early diagnosis resulting in conservative treatment approaches.

INTRODUCTION

Squamous cell carcinoma (SCC) is the most common malignant tumor of the oral cavity and constitutes 90% of all oral neoplasms. The incidence of oral SCC (OSCC) is evidencing an upward trend signaling an increase in incidence and mortality rates. Around 300,000 patients are annually estimated to have oral cancer globally. It accounts for 4% of cancers in men and 2% of cancers in women and the stage at diagnosis determines the prognosis to a large extent.[1]

The relative incidence of OSCC is reported as 35% for the lower lip, 25% for ventral surface of the tongue, 20% for floor of the mouth, 15% for the soft palate, 4% for gingiva/alveolar ridge and 1% for the buccal mucosa.[2] Gingival SCC (GSCC) is an uncommon condition with a likely predilection for females.[3] It clinically presents as an exophytic mass with a granular, papillary, or verrucous surface or as an ulcerative lesion.[4]

GSCC is an insidious lesion that is usually asymptomatic and is commonly misdiagnosed as one of the many inflammatory lesions of the periodontium such as periodontitis, pyogenic granuloma, papilloma or an inflammatory hyperplasia.[5] It typically arises from the keratinized mucosa, commonly in a posterior site destroying the underlying alveolar bone leading to tooth mobility.[6] Unlike tobacco and alcohol consumption, which are significant risk factors for OSCC,[3] GSCC is weakly or least associated with them.[6] It is generally agreed that GSCC is more common in the mandible than the maxilla[7] and 60% of those are located posterior to premolars.[8]

Although GSCC is amenable to early detection due to its direct visibility and the ease of clinical examination, it can easily be misinterpreted and overlooked as a periodontal lesion or an ulcer resulting in the delay of diagnosis and treatment affecting the prognosis.[9] A case of GSCC affecting the mandibular anterior lingual gingiva masquerading as an aphthous ulcer is presented which buttresses the above viewpoint.

CASE REPORT

A 38-year-old Indian woman reported to the Department of Periodontics, Government Dental College and Hospital, Hyderabad, India in July 2011 with a chief complaint of burning sensation and itching in relation to mandibular anterior lingual gingiva for past 1 month. Patient had provided informed consent to be profiled. Past dental history revealed that the patient had visited a couple of private general dental practitioners where the lesion was misdiagnosed as an aphthous ulcer and palliative care was provided for the same. As there was no improvement in her complaint, she decided to come to the dental school for an additional opinion. She was referred for diagnosis and treatment in post-graduate periodontics clinic. There was no contributing medical or family history except that the patient had undergone hysterectomy and appendectomy 10 years back. Patient was in good health and denied any deleterious habits like smoking, alcohol consumption or recreational drug use. No lymph nodes were palpable or tender in a head and neck examination.

Intraoral examination revealed a clean mouth with good gingival health and minimal deposits with the full complement of teeth. Clinical examination of the lingual gingiva revealed a 1 cm × 1 cm ulcer extending mesiodistally from mid lingual surface of 41 to mesiolingual surface of 43 and corono-apically from the gingival margin to the floor of the mouth, not extending beyond the anterior part of lingual frenum. The surface of the lesion appeared to be ulcerated and pebbly with isolated areas of erythema and had well-defined borders that were found to be in level with the adjacent tissue. The ulcerated part of the lesion had rhomboid appearance. The surface of lesion toward the lingual frenum appeared to have a shaggy base covered with slough and there was no exudation [Figure 1]. Intraoral periapical X-ray showed bone loss extending up to the apical 3rd in relation to 41, 42 [Figure 2]. Since the clinical findings of the existing lesion didn’t correlate with any of the features of periodontal lesions and the fact that it has been present for the past 1 month was enough to suspect a malignant ulcer. At this stage, a provisional diagnosis of GSCC was made and after obtaining the patient's consent, an incisional biopsy was taken immediately. The specimen was then sent for histopathological examination.

Figure 1

Clinical lingual view showing the ulcerative lesion

Figure 2

Intraoral periapical showing bone loss in relation to 41, 42

Histopathology

The histological examination of the soft-tissue specimen revealed severe dysplastic changes of the epithelium. There were many sheets and clusters of cells, which were polygonal in shape and contained moderate to abundant pale acidophilic cytoplasm and sharp cellular margins. The nucleus was round to oval in shape and showed moderate pleomorphism, disorganization, coarse chromatin clumping and prominent nucleoli. Mitotic activity was high. There were patchy dense infiltrates of lymphocytes, plasma cells and neutrophils [Figure 3]. A clear and prominent feature was the presence of multiple, keratin pearls in connective tissue [Figure 4]. The above clinical and histological features are conclusive of invasive keratinizing GSCC.

Figure 3

Histopathological examination showing proliferation of basal cell layer and neoplastic epithelial cells in the connective tissue (H and E, ×40)

Figure 4

Keratin pearls inside the connective tissue seen in higher magnification (H and E, ×100)

The patient was immediately referred to a specialty hospital for cancer (Indo-American Cancer Institute, Hyderabad, India) where a computed tomography scan was taken to evaluate any alveolar bone invasion. Subsequently, the lesion was staged as T1N0M0. The involved teeth 41, 42 were extracted and the lesion was treated with radiation therapy alone (intensity modulated radiation therapy, 6600 U/33 fractions using ×6 photons). Six months follow-up revealed uneventful healing and no recurrence.

DISCUSSION

SCC being a common neoplasm is a well-documented lesion in the dental literature in terms of its pathogenesis, sites affected, diagnosis, treatment and prognosis.[10] Despite this, the literature on GSCC is scarce. The authors admit that this lacuna in literature is due to the fact that this entity is considered as a part of oral cancers in general.[111213] There is a need to document GSCC as a separate entity as it exhibits features different from general OSCC. These include its direct invasion of the bone,[14] its predilection for females unlike OSCC which is generally seen in males[3] and the least association with the classic risk factors of tobacco and alcohol consumption.[6] The fact that it resembles periodontal disease[15] or an endo-perio lesion[14] or an ulcer as in the present case may make it go unnoticed by a complacent or casual examiner. This in turn could lead to diagnosis at advanced stages with poorer prognosis and possible life threatening complications.

Henceforth, dentists in general and periodontists in particular must stress on a thorough intraoral examination and it is wise to lay special emphasis on lesions that remain after the elimination of local factors such as plaque, calculus etc., The need for biopsy in these lesions must not be underestimated as histopathological examination is the gold standard to conclude the final diagnosis. This view of the authors is identical with the observations of Khan et al.[16] and Seoane et al.[17]

The present case report is unique in terms of its anatomic location, i.e., the lingual gingiva of mandibular region near the lingual frenum. It could have easily been misinterpreted as an aphthous ulcer. It is uncommon for an aphthous ulcer to present on the attached gingiva but such cases have been documented in the literature.[18] Earlier studies on GSCC have reported the lesion on posterior mandible,[16192021] posterior maxilla,[1422] anterior maxilla[1523] and anterior mandible.[24] To the best of our knowledge, this is the first case report on the above mentioned anatomic location.

GSCC is a rare human neoplasm with direct bone invasion and most of the cases are diagnosed at an advanced stage[17] requiring treatment procedures such as radical neck dissection, rim or segmental resection of mandible or maxilla. This calls for an early diagnosis and management of the lesion to decrease morbidity and subsequent mortality resulting from GSCC.

The present case can be termed as an early diagnosis as it was diagnosed within 40 days. This total diagnostic time (relative time from when patients first become aware of the problem to histopathological diagnosis) is well within the limits of 45 days[17] and 46 days[25] diagnostic time intervals. The conservative treatment approach of radiation therapy alone in this case can be solely attributed to early diagnosis. The fact that these oral lesions are more likely to be diagnosed in a dental setting by a general dental practitioner or periodontist during routine dental appointments[26] necessitates the need for an astute eye during intraoral examinations.

CONCLUSIONS

Lesions of the gingiva and oral soft-tissues not responding to conventional therapy should alert the dentist regarding the possible chances of encountering a neoplasm. A biopsy to confirm the diagnosis and prompt referrals can significantly improve the prognosis and decrease the morbidity and mortality.