Case report

Squamous odontogenic tumor associated with an erupting maxillary canine: case report

Squamous odontogenic tumor (SOT) is a rare, benign, locally infiltrative odontogenic tumor of the gnathic bones. It is composed of islands of bland, well-differentiated squamous epithelium of varying shape and size. Because of histologic overlap, SOT has often been overdiagnosed as ameloblastoma and squamous cell carcinoma. It thus becomes important to understand the clinical, radiologic, histopathologic, and treatment characteristics of this tumor.

Using the PubMed and Google Scholar databases, we searched for reported cases of SOT published in the English-language literature. We were able to retrieve 49 acceptable cases and perform a comprehensive literature review of the intraosseous SOTs, with emphasis on their clinical, radiographic, and pathologic characteristics, as well as treatment strategies. In addition, we present an additional case of SOT affecting the posterior mandible in a 44-year-old female patient.

The tumor in the posterior mandible in our patient was accompanied by acute pain and treated by enucleation. Histopathologic evaluation showed variably sized islands of benign squamous epithelium scattered in a fibrous stroma, consistent with the diagnosis of an SOT. Uneventful healing was noted at the 1-month postoperative appointment. However, the patient was lost to long-term follow-up. Our literature review showed that the average age at the time of diagnosis of SOT is 34.2 years. Men and women are equally affected, and the tumor does not show a predilection for either jaw bone. The most common locations are the anterior maxilla and posterior mandible. Most SOTs are treated conservatively by enucleation or curettage, whereas aggressive or recurrent tumors require radical resection.

Careful evaluation of the excised specimen, with immunohistochemical investigations, may prove rewarding in differentiating an SOT from other odontogenic neoplasms and thus minimize the patient's chances of undergoing an unnecessary aggressive intervention.

Odontogenic cysts and tumors represent a surprisingly diverse group of lesions of the jaws and overlying soft tissues. In general, odontogenic cysts may be developmental or inflammatory in origin. Developmental odontogenic cysts include the following: the dentigerous cyst, eruption cyst, odontogenic keratocyst, orthokeratinized odontogenic cyst, gingival cyst of the newborn, gingival cyst of the adult, lateral periodontal cyst, glandular odontogenic cyst, and calcifying odontogenic cyst. Inflammatory odontogenic cysts include periapical cysts and residual periapical cysts. In general, odontogenic cysts are benign, although malignant transformation is possible. Benign odontogenic tumors may be subclassified as follows: (1) epithelial (including ameloblastoma, calcifying epithelial odontogenic tumor, squamous odontogenic tumor, and adenomatoid odontogenic tumor); (2) mixed epithelial and mesenchymal (including ameloblastic fibroma, ameloblastic fibroodontoma, odontoma, primordial odontogenic tumor, odontoameloblastoma, and dentinogenic ghost cell tumor); and (3) mesenchymal (including central odontogenic fibroma, peripheral odontogenic fibroma, granular cell odontogenic tumor, and odontogenic myxoma). Furthermore, there are several types of malignant odontogenic tumors, including metastasizing ameloblastoma, ameloblastic carcinoma, primary intraosseous squamous cell carcinoma, clear cell odontogenic carcinoma, ghost cell odontogenic carcinoma, intraosseous mucoepidermoid carcinoma, ameloblastic fibrosarcoma, and odontogenic carcinosarcoma. The diversity of odontogenic cysts and tumors can be difficult to understand without basic knowledge of the process of odontogenesis. Hence, we begin with a review of the histology and embryology of tooth formation. In addition, clinical correlation is often essential for accurate diagnosis. Therefore we discuss the clinical features, as well as pathologic features, differential diagnosis, treatment, and prognosis for each entity.

We reported a very rare case of squamous odontogenic tumor(SOT) in a 23-year-old female. The tumor arose after an implanting operation of an orthodontic micro-screw, and was definitely diagnosed by the histopathological examination. Based on the case report and a review of the literature, we discussed about the general features, differential diagnosis and pathogenesis of SOT.

Squamous odontogenic tumor is a rare benign epithelial odontogenic tumor of the jaw. Most are solitary lesions, although rare multifocal lesions have been described. Maxillary lesions have more aggressive behavior. Because of their benign character, these lesions are usually treated using a conservative surgical approach with curettage and surgical enucleation. This report describes the case of a 29-year-old woman with multifocal lesions who was initially treated with conservative surgical therapy. Early recurrence 6 months after surgery prompted more aggressive resection. This case is discussed in the context of current evidence related to the epidemiology, etiology, diagnosis, and therapy of squamous odontogenic tumors.