Unusual case of carcinoma cuniculatum affecting the oral cavity of an 11-year-old boy

ral Carcinoma Cuniculatum (OCC) corresponds to a rare, ell-differentiated variant of Oral Squamous Cell Carcioma (OSCC) first included in the World Health Organization WHO) Classification of Head and Neck tumors in 2005. ccording to the WHO, OCC is defined as a malignant neolastic proliferation of stratified squamous epithelium in road processes with keratin cores and keratin-filled crypts hich seem to burrow into the bone, without obvious cytoogical features of malignancy.1 It is estimated that OCC

Clinical presentation: mass involving both the buccal and lingual gingiva between the lower left second molar and lower left first premolar. a solid variant of an odontogenic keratocyst was done due to its histopathological similarity. The CT scan examination revealed no lymph node involvement and no metastasis, and the patient was referred for surgical treatment. The patient was controlled with regularity and no recurrences have been observed after a 5-years-follow up period.
Carcinoma Cuniculatum (CC) is a rare, low-grade variant of Squamous Cell Carcinoma (SCC) most commonly located on the plant of the foot, but any anatomic site can be affected, including the oral cavity. 2 According to a recent systemic review that analyzed 43 cases of OCC, this tumor has a slight predilection for females, being more frequent between the sixth and seventh decade of life. 3 Our case is the second report of an OCC in children. The first case was reported by Hutton el al. in 2010, which corresponded to an OCC affecting the anterior maxillary gingiva of a 7-yearold girl. 4 When affecting the oral cavity, the most common location is the mandibular gingiva followed by the maxillary gingiva. 3 Cases affecting the alveolar ridge, tongue and palate have also been reported. 5 When affecting the gingiva, bone involvement is common. Imaging usually shows a radiolucency with ill-defined margins reabsorbing the adjacent cortical bone. 6 The most common clinical symptom is pain, followed by ulceration, swelling, and induration. 3,5,6 Our patient apart from the aforementioned symptoms also reported paresthesia, which to our knowledge, has not been reported before. The main differential diagnosis of CC is Verrucous Carcinoma (VC), another well-differentiated uncommon variant of SCC. But other keratinizing lesions, such as keratinizing odontogenic cysts have to be ruled out, especially with CASE LETTER Figure 2 Cone-beam computed tomography. Axial (A) and para-axial (B) sections and panoramic reconstruction (C). There is a well-defined large radiolucency involving the whole thickness of the posterior left mandible perforating the buccal bone plate. dealing with small incisional biopsies. In the early days, CC was thought to be a VC, but is now considered a distinct entity of SCC. 2 Clinically, both CC and VC can have a verrucous appearance, although CC might exhibit a sessile pink-reddish papillary surface, which is not observed in VC. Histologically, CC shows a tortuous invasive (endophytic) component with keratin plugging, which contrasts with the more exophytic verrucous growth and ''pushing borders'' observed in VC. 5 Microabscesses filled with neutrophils are also commonly reported in CC. 2 The main treatment of choice is surgical excision. Although OCC can be locally aggressive, lymph node and distant metastases are uncommon, 2,6 and the 5-year survival rate has been reported above 90%. 2 Local recurrences have been reported, but are not very common. In respect to our case, the patient remained disease-free after a follow-up period of 5 years.

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Conflicts of interest
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This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The study was done in Viña del Mar, Chile.