Squamous cell carcinoma arising from a keratocystic odontogenic tumor

Orthokeratinized odontogenic cyst: Report of eight cases and review of literature regarding its malignant transformation

Orthokeratinized odontogenic cyst (OOC) is an uncommon odontogenic cyst. It has been categorized as a subtype of odontogenic keratocyst (OKC). In 2005, it was classified as a distinct entity. OOC should be histopathologically differentiated from OKC, which has a higher recurrence rate and lower malignant potential. In addition, OOC should be examined for malignant transformation. The epithelium of odontogenic cysts may rarely show malignant transformation. However, malignant transformation has been reported in inflammatory cysts such as the residual cyst and periapical cyst. The number of carcinomas arising from an OOC is low. This paper describes eight cases of OOC; out of which, two showed the development of squamous cell carcinoma from their epithelial lining.

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.

Squamous cell carcinoma arising from a keratocystic odontogenic tumor: a case report

Background

The term “primary intraosseous squamous cell carcinoma” was introduced in 2005 by the World Health Organization with three subcategories. Squamous cell carcinoma arising from the lining of an odontogenic cyst is one important rare subcategory of such lesions with an incidence of 0.01 to 0.02%. Furthermore, the appearance of such malignancy in an odontogenic tumor such as keratocystic odontogenic tumor is considered extremely rare.

Case presentation

In this case report we report a case of a 50-year-old Sri Lankan woman who complained of pain and increase in the size of a swelling at the anterior mandible, which had been present for over 1 year. The increase was significant for 1 month with accompanying numbness of the left half of her lip. Cone beam computed tomography results revealed an irregular radiolucent lesion involving most of her mandible and, except in the anterior part, very little buccolingual expansion was seen that suggested a keratocystic odontogenic tumor. An excision biopsy of the cyst lining confirmed a squamous cell carcinoma arising from a preexisting keratocystic odontogenic tumor.

Conclusions

Even though primary intraosseous squamous cell carcinoma arising from a keratocystic odontogenic tumor is considered to be very rare, the present case is comparable to most of the aspects cited in the literature. The current case emphasizes the importance of careful investigation of swellings present in the mandible. Clinicians as well as patients should be aware and detect these changes to avoid being clinically negligent.

Squamous cell carcinoma arising within a maxillary odontogenic keratocyst: A rare occurrence

Squamous cell carcinoma (SCC) arising within the lining of an odontogenic keratocyst (OKC) is a rare occurrence. Although potentially locally destructive, OKC is a benign odontogenic process that typically presents with clinical and radiographic features characteristic of a benign intraosseous neoplasm. We present the clinical and radiographic features of a maxillary mass that demonstrated SCC arising from the lining of an OKC. Although the initial clinical and radiographic presentation suggested an infection or malignant neoplasm, biopsies revealed an infiltrative well-differentiated SCC contiguous with and arising from the focus of a pre-existing OKC. The patient subsequently underwent a type II hemi-maxillectomy with neoadjuvant chemoradiation. This report discusses the clinical and radiographic features associated with intraosseous malignancies, especially those arising from an otherwise benign odontogenic lesion. While the majority of OKCs are benign, the current report illustrates the potential for carcinomatous transformation within the lining of an OKC.