Malignant transformation of keratocystic odontogenic tumor: two case reports

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.

Peripheral intraosseous carcinoma arising from a recurrent odontogenic keratocyst

Primary intraosseous carcinoma (PIOC) is a distinct clinical and genomic pathology that should be considered when treating aggressive odontogenic cysts refractory to standard treatments. Odontogenic cysts have a very low chance of malignant transformation, with most studies citing an incidence of <0.05%. The pathogenesis of PIOC is multifactorial, with chronic inflammation-induced carcinogenesis being the most cited theory. Early detection is imperative to enhance the patient's prognosis, with the 5-year overall survival rate of PIOC being 38%. This paper presents a case of PIOC and reviews data on its epidemiology, diagnosis, presentation, and treatment.

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.

Activation of mesenchymal stem cells promotes new bone formation within dentigerous cyst

Background

Dentigerous cyst (DC) is a bone destructive disease and remains a challenge for clinicians. Marsupialization enables the bone to regenerate with capsule maintaining, making it a preferred therapeutic means for DC adjacent to vital anatomical structures. Given that capsules of DC are derived from odontogenic epithelium remnants at the embryonic stage, we investigated whether there were mesenchymal stem cells (MSCs) located in DC capsules and the role that they played in the bone regeneration after marsupialization.

Methods

Samples obtained before and after marsupialization were used for histological detection and cell culture. The stemness of cells isolated from fresh tissues was analyzed by morphology, surface marker, and multi-differentiation assays. Comparison of proliferation ability between MSCs isolated from DC capsules before (Bm-DCSCs) and after (Am-DCSCs) marsupialization was evaluated by Cell Counting Kit-8 (CCK-8), fibroblast colony-forming units (CFU-F), and 5′-ethynyl-2′-deoxyuridine (EdU) assay. Their osteogenic capacity in vitro was detected by alkaline phosphatase (ALP) and Alizarin Red staining (ARS), combined with real-time polymerase chain reaction (RT-PCR) and immunofluorescence (IF) staining. Subcutaneous ectopic osteogenesis as well as cranial bone defect model in nude mice was performed to detect their bone regeneration and bone defect repairability.

Results

Bone tissue and strong ALP activity were detected in the capsule of DC after marsupialization. Two types of MSCs were isolated from fibrous capsules of DC both before (Bm-DCSCs) and after (Am-DCSCs) marsupialization. These fibroblast-like, colony-forming cells expressed MSC markers (CD44+, CD90+, CD31−, CD34−, CD45−), and they could differentiate into osteoblast-, adipocyte-, and chondrocyte-like cells under induction. Notably, Am-DCSCs performed better in cell proliferation and self-renewal. Moreover, Am-DCSCs showed a greater osteogenic capacity both in vitro and in vivo compared with Bm-DCSCs.

Conclusions

There are MSCs residing in capsules of DC, and the cell viability as well as the osteogenic capacity of them is largely enhanced after marsupialization. Our findings suggested that MSCs might play a crucial role in the healing process of DC after marsupialization, thus providing new insight into the treatment for DC by promoting the osteogenic differentiation of MSCs inside capsules.

Reduced delay in diagnosis of odontogenic keratocysts with malignant transformation: A case report

BACKGROUND

In rare cases, odontogenic keratocysts (ODs) transform into squamous cell carcinoma. Intervals between the first attendance of a patient and the diagnosis of OD with malignant transformation vary from weeks to years. In this article, we report a case of malignancy derived from OD with a five-day delay in diagnosis.

CASE SUMMARY

A 54-year-old woman was referred to Tongji Hospital in Wuhan, China with complaints of moderate pain, recurrent swelling, and pus discharge around her left maxillary lateral incisor for over 10 years. Physical examination revealed a fistula at the palatine-side mucoperiosteum of the left maxillary lateral incisor and enlarged lymph node in the left neck. Cone beam computed tomography revealed a cystic lesion with massive bone destruction from the left maxillary central incisor to the left secondary maxillary premolar and local bony destruction in the left first mandibular molar. The patient was clinically diagnosed with OD. Enucleation rather than marsupialization was performed given the risk factors of long history, recent aggravated pain, and massive bony destruction. Malignant transformation of OD was confirmed by pathologists 3 d after the operation. Radical surgery was performed, and lymph node metastasis was observed. The patient was subjected to postoperative radiotherapy and synchronous chemotherapy, and no local recurrence or distant metastasis was noted at one-year follow-up.

CONCLUSION

Our case suggests that clinicians should be aware of the malignant transformation of OD, especially when patients present with a long history, massive cyst, chronic inflammation, recent persistent infections, aggravated pain, numbness around the cystic lesion, and lymph node enlargement.

HIF-1α is Overexpressed in Odontogenic Keratocyst Suggesting Activation of HIF-1α and NOTCH1 Signaling Pathways

Background: The odontogenic keratocyst (OKC) is an odontogenic cyst that shows aggressive and intriguing biological behavior. It is suggested that a hypoxic environment occurs in OKC, which led us to investigate the immunoexpression and location of hypoxia-inducible factor 1-alpha (HIF-1α) and other hypoxia-related proteins. Methods: Twenty cases of OKC were evaluated for the expression of Notch homolog 1 (NOTCH1), HIF-1α, disintegrin and metalloproteinase domain-containing protein 12 (ADAM-12), and heparin-binding epidermal growth factor-like growth factor (HBEGF) by immunohistochemistry and compared to eight control cases of calcifying odontogenic cystic (COC), orthokeratinized odontogenic cyst (OOC), and normal oral mucosa (OM) in basal and parabasal layers. Results: In OKC, all the proteins tested were expressed significantly higher in both basal (except for NOTCH1 and HBEGF in OOC) and suprabasal epithelial layers compared to controls. Looking at the epithelial layers within OKC, we observed an increased NOTCH1 and HIF-1α expression in parabasal layers. Conclusions: These results suggest that hypoxia occurs more intensively in OKC compared to COC, OM, and OOC. Hypoxia appeared to be stronger in parabasal layers as observed by higher HIF-1α expression in upper cells. Overexpression of NOTCH1, ADAM-12, and HBEGF in OKC was observed, which suggests that microenvironmental hypoxia could potentially regulate the expression of hypoxia-related proteins, and consequently, its clinical and biological behavior.

Volume change pattern of decompression of mandibular odontogenic keratocyst

Objectives

This study was aimed to analyze the reducing pattern of decompression on mandibular odontogenic keratocyst and to determine the proper time for secondary enucleation.

Materials and methods

Seventeen patients with OKC of the mandible were treated by decompression. Forty-five series of CT data were taken during decompression and measured by using InVivo software (Anatomage, San Jose, Calif) and were analyzed.

Results

The expected relative volume during decompression is calculated using the following formula: V(t) = V _initial × exp.(at + 1/2bt ²) (t = duration after decompression (day)). There was no significant directional indicator in the rate of reduction between buccolingual and mesiodistal widths.

Conclusion

The volume reduction rate gradually decreased, and 270 days were required for 50% volume reduction following decompression of OKC. The surgeon should be aware of this pattern to determine the timing for definitive enucleation.

Clinical relevance

The volume reduction rate and pattern of decompression of the OKC can be predicted and clinicians should be considered when treating OKC via decompression.

Primary intraosseous squamous cell carcinoma of the mandible arising from an infected odontogenic cyst: A case report and review of the literature

Primary intraosseous squamous cell carcinoma (PIOSCC) derived from a odontogenic cyst is a rare form of odontogenic carcinoma. The incidence of carcinomas arising from odontogenic cysts is particularly uncommon and is reported to occur in 1-2 individuals for every 1,000 cases. The present case describes a 25-year-old man who was initially diagnosed with a chronically infected odontogenic cyst of the mandible. Biopsy and subsequent histology revealed the presence of squamous cell carcinoma. Therefore, neck dissection and hemimandibulectomy were performed. Ultimately, the situation in the mouth healed, though with a severe amount of scarring. Although the development of PIOSCC from an odontogenic cyst is rare, it should be included in the differential diagnosis for jaw bone radiolucency.

Primary intraosseous squamous cell carcinoma of the mandible: a case with atypical imaging features

Primary intraosseous squamous cell carcinoma is a rare malignant tumour that exclusively arises within the jaws. Its diagnosis requires an appropriate clinical, imaging and histological correlation. The exclusion of primary oral mucosa lesions and metastatic disease is mandatory. We report an atypical imaging appearance of this uncommon entity, characterized by new bone formation and periosteal reaction that resemble sarcomatous or malignant odontogenic tumours. A comprehensive discussion on the embryological principles of primary intraosseous squamous cell carcinoma is also provided.

Mandibular intraosseous squamous cell carcinoma lesion associated with odontogenic keratocyst: a case report

Squamous cell carcinoma (SCC) is the most common malignant tumor in the oral cavity, and it accounts for about 90% of all oral cancers. Several risk factors for oral SCC have been identified; however, SCC associated with odontogenic keratocysts have rarely been reported. The present study describes the case of a 36-year-old man with SCC of the right ramus of the mandible, which was initially diagnosed as a benign odontogenic cyst. He underwent enucleation at another hospital followed by segmental mandibulectomy and fibular free flap reconstruction at our institution. In this case, we introduce a patient with oral cancer associated with odontogenic cyst on the mandible and report a satisfactory outcome with wide resection and immediate free flap reconstruction.

Conservative treatment protocol of keratocystic odontogenic tumor: report of a case with nevoid Basal cell carcinoma syndrome and literature review

Keratocystic odontogenic tumor (KOT) is one of the major components of nevoid basal cell carcinoma syndrome (NBCCS), which usually occurs in young ages and includes significant structures of jaws. According to high recurrence rate of KOT, there are many controversies in treatment of the lesion, especially in syndromic cases with younger ages. In current report, authors suggest a conservative protocol in the treatment of KOT in a patient with NBCCS.