Primary intraosseous squamous cell carcinoma arising from keratocystic odontogenic tumor

A retrospective study of the malignant change of odontogenic keratocyst

The odontogenic keratocyst (OKC) is a common cystic lesion of the maxilla and mandible. Squamous cell carcinoma (SCC) arising from OKC or dysplasia occurring in OKC is rare. This study aimed to explore the incidence and clinical features of the dysplasia and malignant transformation of OKC. In this study, 544 patients diagnosed with OKC were collected. Among them, 3 patients were diagnosed as SCC arising from OKC, and 12 patients were diagnosed as OKC with dysplasia. The incidence was calculated. Clinical features were analyzed by chi-square test. In addition, a representative case reconstructing mandible with vascularized fibula flap under general anesthesia was reported. And cases reported before were reviewed. The incidence of the dysplasia and malignant transformation of OKC, which are highly associated with the clinical features of swelling and chronic inflammation, is about 2.76%. But the relevance between the dysplasia and malignant transformation and age, gender together with pain is not statistically high. All in all, the clinical features of swelling and chronic inflammation can be considered as characteristics of the dysplasia and malignant transformation of OKC. Although the pain isn't statistically relevant, it may be a dangerous clew. Also, combined with earlier literatures, the dysplasia and malignant transformation of OKC shows unique features of radiographs and histopathology.

Primary intraosseous squamous cell carcinoma arising from an odontogenic keratocyst: case series and literature review

Background

The aim of this study was to investigate the clinicopathologic features of primary intraosseous squamous cell carcinoma arising from an odontogenic keratocyst (PIOSCC ex OKC) and comprehensively improve the understanding of this disease.

Material and Methods

We retrospectively investigated five cases of PIOSCC ex OKC at Peking University School and Hospital of Stomatology. We also conducted a systematic review of studies on PIOSCC ex OKC by using online databases from their inception until February 2020.

Results

In our series of five cases, all lesions were located in the mandible. Three cases (60%) showed recurrent OKCs and two cases (40%) showed primary OKCs. During the follow-up period, one patient died of local relapse. No patients developed metastasis. On the basis of our literature survey, we selected 22 articles reporting 29 patients with PIOSCC ex OKC. Seven of these patients (24.1%) showed local recurrence, three patients (10.3%) developed cervical metastasis, three patients (10.3%) developed distant metastasis (in the pleura in one case and in the lung in two cases), and seven patients died from the disease during the follow-up period. The disease-specific 5-year survival rate in the study group was 53.2%. Through univariate and multivariate analysis, local recurrence was identified as the only significant independent prognostic factor for survival (P < 0.05).

Conclusions

The results suggest that PIOSCC ex OKC is a rare intermediate-grade malignancy. Although elective neck dissection is typically unnecessary, adequate therapy should be applied to achieve the lowest local recurrence rate possible to ensure a favorable survival rate.

Key words:Primary intraosseous squamous cell carcinoma, odontogenic keratocyst, prognosis.

Carcinomatous Transformation of Odontogenic Keratocyst and Primary Intraosseous Carcinoma: A Systematic Review and Report of a Case

PURPOSE

To assess the prognostic findings of the carcinomatous transformation of odontogenic keratocyst (OKC).

METHODS

A systematic review of all cases of carcinomatous transformation of OKC was completed, and a case report was included.

RESULTS

A total of 679 publications were screened, and 37 cases met inclusion criteria. The mean age for patients with malignant transformation of OKC was 45.1 years. Pain (67.5%) and swelling (78.3%) were the most common symptoms. The malignant transformation occurred with increased frequency in the posterior mandible and larger lesions that span greater than 2 subunits of the involved jaw. Resection was the definitive treatment in all cases and 14 cases (46%) utilized adjuvant treatment.

CONCLUSIONS

Patient outcomes and follow-up was variable in our study such that overall survival was difficult to determine. However, overall survival in malignant transformation of odontogenic cysts of all kinds ranges from 62 to 85% and 30 to 8% for 2 and 5 years, respectively.

Primary Intraosseous Squamous Cell Carcinoma Involving the Jaw Bones: A Systematic Review and Update

Primary intraosseous oral squamous cell carcinoma (PIOSCC) is a rare malignant neoplasm that affects the jaws. Despite its aggressive biological behavior, there are no studies that evaluated the clinicopathological features of this tumor and parameters associated with its prognosis. The objective of the present study was to conduct a systematic review of the available data on oral and maxillofacial PIOSCC in order to determine its clinicopathological characteristics and biological behavior. We conducted a systematic review in May 2020 in multiple databases using a specific search strategy. Cases diagnosed as PIOSCC in the oral cavity and maxillofacial complex that had sufficient histopathological data, absence of ulceration in the oral mucosa, a negative result for a distant primary tumor, and radiographic evidence of an osteolytic lesion that was entirely or mostly surrounded by the jaw bones were included. A total of 109 published articles were included in our systematic review, corresponding to 257 cases. PIOSCC showed a male predilection (69.3%) and a preference for the mandible (7:1), with the posterior region being the most commonly affected site. The mean age at diagnosis was 57.3 years. Cortical expansion, pain, and lip/facial paresthesia were the most common clinical features. Regarding histopathological features, most PIOSCC were well-differentiated and the solid subtype was the most common. Statistical analysis showed that PIOSCC located in the mandible (p = 0.03) and recurrence (p < 0.01) were significantly associated with a higher mortality rate. PIOSCC has a poor prognosis, with high rates of mortality.

Complete removal of dentigerous cysts with preservation of associated teeth as an alternative to marsupialization in children and preadolescents

The aim of this study is to evaluate the results of dentigerous cysts enucleation with preservation of cyst-associated teeth as a single procedure in a group of children and preadolescents. A retrospective case series of seven patients with 15 unerupted developing teeth associated with or adjacent to dentigerous cysts was conducted. Patients were treated using the uniform surgical protocol (cystectomy, preservation of cyst-associated teeth, without use of orthodontic traction, primary wound closure). The metric analysis of the cysts and unerupted teeth on CBCT and an evaluation of the state of involved teeth after the treatment was performed. The mean age of patients was 9.0 ± 2.1 years (range 5-12 years, median = 9 years). All teeth erupted spontaneously. No serious postoperative complications or recurrences of lesions were detected. The mean follow-up was 53.1 ± 15.7 months (range 25-71 months, median = 52 months). The cystectomy of dentigerous cysts with preservation of associated teeth may be considered an alternative to marsupialization in children and preadolescents.

Pediatric case of squamous cell carcinoma arising from a keratocystic odontogenic tumor

Keratocystic odontogenic tumors (KCOT) are exceptional in children and adolescents as they usually occur in the third decade. The present study reports the case of a 15 years old girl who was diagnosed with a KCOT that underwent malignant transformation. KCOT diagnostic was based on clinical, radiological, histopathological and immunohistochemical findings. A conservative treatment by enucleation was performed. Histopathological analysis of the surgical specimen concluded to a KCOT, with an infra-centimetric focus of well-differentiated squamous cell carcinoma. Owing to the well-differentiated character of the squamous cell carcinoma, a single clinical and MRI surveillance every 3 months was decided, without complementary treatment.

Minimally Invasive Treatment for Hard Palate-Invading Maxillary Keratocystic Odontogenic Tumor

Keratocystic odontogenic tumor (KCOT) is one of the benign developmental odontogenic cystic lesions arising from impacted teeth. In comparison to other odontogenic cysts, such as radicular cysts and dentigerous cysts, KCOT is known to be more aggressive and is associated with a relatively high recurrence rate. Traditionally, KCOT has been treated with total resection through sublabial incision. Marsupialization is advocated to reduce surgical invasion. However in all the cases, marsupialization was performed in the oral cavity. With the recent development of appropriate instruments and the endoscopic modified medial maxillectomy (EMMM) technique, which allows preservation of the inferior turbinate and nasolacrimal duct, an exclusive endoscopic approach to KCOT becomes possible. However, when the KCOT invades the hard palate, total resection of the tumor requires subtotal maxillectomy including hard palate. Consequently, as the maxillary sinus connects to the oral cavity, life-long use of a prosthesis becomes mandatory. Here we report a case of a seventeen-year-old female with a hard palate-invading KCOT who was successfully treated with the EMMM approach. The KCOT was fenestrated to the nasal cavity, leading to preservation of the hard palate. The lesion invading the hard palate was found to remain unchanged over one year upon follow-up. The trans-nasal approach with EMMM is a direct, minimally invasive method providing a direct field of view for the treatment of maxillary odontogenic cysts. Marsupialization of the KCOT with the EMMM technique might be a viable treatment option if the maxillary KCOT invades surrounding structures.