Ameloblastic carcinoma: A clinicopathologic dilemma - Report of two cases with total review of literature from 1984 to 2012

Valente FA. Ameloblastic carcinoma of the mandible: A case report

Ameloblastic carcinoma (AC) is a rare, primary epithelial odontogenic malignant neoplasm. It is the malignant counterpart of ameloblastoma. It comprises 1% of all cysts and tumours occurring in the jaws, arising from tissues associated with odontogenic epithelium. The objective of the present study was to describe a clinical case of a 63-year-old male with an enlargement in the mandible on the left side. Panoramic radiography revealed a radiolucent area with poorly defined borders, and an incisional biopsy was performed for the histopathological study using immunomarkers such as SOX2 and Ki-67. Ki-67 is considered a marker of cell proliferation, and SOX2 reportedly participates in the development of the ameloblastic epithelium lineage and is associated with a more aggressive clinical course. A final histopathological diagnosis of AC was given. Unfortunately, the patient died one week before surgical resection (the surgical treatment of choice for AC).

Rare Ameloblastic Carcinoma Metastasis to the Cervical Spine: A Case Report

BACKGROUND AND IMPORTANCE

Ameloblastic carcinoma (AC) is a malignant neoplasm of epithelial origin that typically arises from the mandible or maxilla. It represents approximately 2% of all odontogenic tumors. Gross total resection is the surgical goal given AC's aggressiveness and propensity for recurrence. We present the first reported AC metastasis to the cervical spine.

CLINICAL PRESENTATION

A 61-yr-old African American female with a history of AC of bilateral mandibles and lung metastases presented with neck pain and right arm weakness progressive over several months. Cervical spine imaging demonstrated a cervical 3 pathological fracture with severe anterior vertebral body compression and resultant cervical 2-3 kyphotic deformity and bony retropulsion causing severe cord compression. The patient underwent a cervical 3 corpectomy and cervical 2-4 anterior fixation followed by a cervical 3 laminectomy and cervical 2-5 dorsal internal fixation and fusion. Postoperatively, the patient's neurological exam remained stable and imaging showed improved spinal alignment and appropriate anterior and posterior instrumentation. Unfortunately, the patient thereafter suffered a decline in performance status and progression of lung metastatic disease. Her oncology team is considering chemotherapy and stereotactic radiosurgery, but her prognosis remains grim.

CONCLUSION

AC is a rare and aggressive pathology with a poor prognosis despite multimodal therapy. We present the first case of AC metastatic spread to the spine. We aim to bring this pathology to the attention of our worldwide neurosurgical colleagues and share our surgical approach and multidisciplinary management to assist those who may encounter this pathology in the future.

Study on clinical and biological characteristics of ameloblastic carcinoma

BACKGROUND

Ameloblastic carcinoma (AC) is an odontogenic malignant tumor which is closely related to benign ameloblastoma. Because of its rarity, diagnosis and treatment are difficult. In this study, we summarized and analyzed the clinical and biological characteristics of AC.

RESULTS

Fifteen patients with AC and a median age of 53 years were identified. Among of them, five patients who were tested carried a BRAF-V600E mutation. Two patients presented with cervical lymph nodes and lung metastases. Primary AC was more invasive, and the bone destruction ability of the primary type was more radical than that of the secondary type.

CONCLUSIONS

This study revealed that the BRAF-V600E mutation was related to the aggressive behavior of AC, and early radical resection is crucial. Moreover, targeted therapy may be a new direction in the future.

Investigation of PTEN promoter methylation in ameloblastoma

Background

Phosphatase and tensin homolog (PTEN) acts as a tumor suppressor gene. Inactivation of PTEN has been reported in various types of cancers. PTEN promoter methylation possibly underlies PTEN inactivation, which results in tumorigenesis. The aim of this study was to investigate whether PTEN promoter methylation contributes to PTEN inactivation in ameloblastoma and its associated protein expression.

Material and Methods

In total, 20 fresh-frozen ameloblastoma samples were evaluated for PTEN promoter methylation using methylation-specific polymerase chain reaction (MS-PCR). A subset of 10 paraffin-embedded ameloblastoma samples was examined for PTEN expression through immunohistochemistry. Four primary cultured ameloblastoma cells were investigated for PTEN promoter methylation and PTEN transcriptional expression via reverse transcription PCR.

Results

PTEN promoter methylation was detected in 65% (13/20) of the ameloblastoma samples. Of 10 ameloblastoma samples, 4 exhibited reduced PTEN expression. Of 5 samples with methylated PTEN, 3 (60%) were associated with loss of PTEN expression. However, PTEN expression was detected in 4 (80%) of 5 samples with unmethylated PTEN. In addition, 3 (75%) of 4 primary ameloblastoma cell cultures exhibited an inverse correlation between PTEN promoter methylation and PTEN transcription level.

Conclusions

PTEN promoter methylation is found in a number of ameloblastomas but not significantly correlated with loss of PTEN expression. Genetic or epigenetic mechanisms other than PTEN promoter methylation may contribute to PTEN inactivation in ameloblastoma tumor cells.

Key words:PTEN, promoter methylation, ameloblastoma.

Ameloblastic carcinoma ex ameloblastoma of the maxilla

Ameloblastic carcinoma (AC) is a rare malignant odontogenic tumor. Approximately 138 cases were reported. The majority of these cases occurred in the mandible. Only 57 cases were located in the maxilla. Most of AC cases occur in a primary type. Little is known about AC secondary type (dedifferentiated) since only six cases have been reported. All of previous six cases occurred in the mandible. Here, we presented the first case of maxillary AC secondary type (dedifferentiated) in a 46-year-old female. The first excisional biopsy was diagnosed as basal cell ameloblastoma. Then, the patient underwent partial maxillectomy. A recurrence occurred 17 months later. At this time, tumor cells with cytological atypia were clearly detected. A diagnosis of AC was rendered. Two years later, the patient suffered from another recurrence and received a wide excision with a diagnosis of AC. We considered our case as AC secondary type (dedifferentiated). We discussed the histopathological findings that may be helpful in making a diagnosis of AC. In addition, we consider that the basaloid pattern may be related to malignant transformation in ameloblastoma.

Ameloblastic Carcinoma In Situ: Review of Literature and a Case Presentation in a Pediatric Patient

Ameloblastic carcinomas are rare malignant lesions with 3 mandibular pediatric cases reported in the literature. We present a case of ameloblastic carcinoma in situ in a 15-year-old male with a right mandibular cystic lesion on computed tomography. The incisional biopsy revealed plexiform ameloblastoma. Due to the infiltrating and aggressive nature of the tumor, the patient underwent hemimandibulectomy and immediate reconstruction with a vascularized osteocutaneous fibula free flap. The final pathology was read as ameloblastic carcinoma in situ. Given the rarity of this disease in the pediatric population, this case report may be a valuable addition to the current literature.

Reconnoitre ameloblastic carcinoma: A prognostic update

AIM

Malignant odontogenic tumor, ameloblastic carcinoma (AC) is challenging to study owing to its rarity, complexity and limited availability of literature. This further makes it difficult to establish its clinical characteristics and prognosis. Our study aimed to evaluate AC's clinico-demographic factors and their relation with prognosis and survival.

MATERIALS AND METHODS

Literature was systematically reviewed for cases pertaining to AC, starting from January 2000 to December 2016. All the required data was obtained, arranged and analysed using Cox regression ratio and Kaplan Meir survival analysis. From the database, 153 cases were retrieved as per the inclusion/exclusion criteria.

RESULTS

The results demonstrated that age of patient, mode of treatment and metastasis affects overall survival. The categorisation of AC as primary or secondary type does not have any role in determining prognosis.

CONCLUSION

Overall survival of AC patient depends upon age, site, treatment and metastasis. For a better prognosis early surgical management of the tumor appears to be the most favourable mode of treatment.

Ameloblastic carcinoma of the maxilla: A case report and an updated review of the literature

Ameloblastic carcinoma (AC) is an uncommon malignant odontogenic tumor that can be difficult to differentiate from ameloblastoma and can arise directly as an undifferentiated lesion or from a pre-existing benign lesion. The current study presents a novel case of primary maxillary AC and review the literature on AC of the maxilla. The review of the literature indicates that secondary tumors and posterior localization are associated with a higher tendency for recurrence and, often, multiple recurrences. Surgical therapy, eventually followed by radiotherapy, is the treatment modality most frequently applied, while the role of chemotherapy remains unclear. Several new cases of maxillary AC have been recently described in literature, making this pathology more frequent than previously considered; this is perhaps an indication of an increased diagnostic sensibility, rather than a real increase in the incidence of the disease itself.

Ameloblastic Carcinoma: A Report of Three Cases

Malignant odontogenic tumours are rare and represent approximately 1% of all oral malignancies. Ameloblastic carcinoma is a rare odontogenic tumour, which is aggressive in nature with extensive local bone destruction that has retained the features of ameloblastic differentiation and also exhibits cytological features of malignancy. It occurs primarily in the mandible in a wide range of age groups. It may arise de-novo or in pre-existing ameloblastoma or odontogenic cyst. The purpose of this report is to present three cases of ameloblastic carcinoma with varying presentations as central and peripheral entities.

Immunohistochemical expression of K6, K8, K16, K17, K19, maspin, syndecan-1 (CD138), α-SMA, and Ki-67 in ameloblastoma and ameloblastic carcinoma: diagnostic and prognostic correlations

OBJECTIVE

To identify cutoff values of markers that correlate with the histopathologic diagnosis of ameloblastic carcinoma (AC) and/or the increased recurrence potential of ameloblastoma (AB).

STUDY DESIGN

Immunohistochemical expression (IHCE) of 9 selected markers were investigated in 18 non-recurrent ameloblastomas (NRABs), 6 recurrent ameloblastomas (RABs), and 5 ACs.

RESULTS

No significant difference in IHCE of K6, K8, K16, K17, K18, K19, maspin, or syndecan-1 was observed among study groups. α Smooth muscle actin (α-SMA)-positive area in central epithelial cells significantly differentiated between AB and AC (P = .017; t -test). Ki-67 score significantly differentiated between AB and AC (P < .005; t -test) and between AC and RAB (P = .015; ANOVA/post hoc).

CONCLUSIONS

Ki-67 score of 75 cells/HPF (ROC curve) is a potential indicator of AC. Clinical recurrence of AB may be predicted by α-SMA expression pattern. Syndecan-1 and α-SMA may indicate a higher aggressive potential of AB when expressed in the stroma.

Incidence and overall survival of malignant ameloblastoma

BACKGROUND

Malignant ameloblastoma, comprising metastasizing ameloblastoma and ameloblastic carcinoma, represents 1.6-2.2% of all odontogenic tumors. Due to its rare nature, malignant ameloblastoma has only been reported in the literature in small case series or case reports. Using the Surveillance, Epidemiology and End-Results (SEER) database, we have performed a population-based study to determine the incidence rate and the absolute survival of malignant ameloblastoma.

METHOD

Using the International Classification of Diseases for Oncology (ICD-O) codes 9310/3 and 9270/3, data from the SEER database were used to calculate the incidence rate and absolute survival rate of population with malignant ameloblastoma.

RESULTS

The overall incidence rate of malignant ameloblastoma was 1.79 per 10 million person/year. The incidence rate was higher in males than females and also higher in black versus white population. The median overall survival was 17.6 years from the time of diagnosis and increasing age was associated with a statistically significant poorer survival.

CONCLUSIONS

To our best knowledge, we report the largest population-based series of malignant ameloblastoma. The incidence rate was 1.79 per 10 million person/year and the overall survival was 17.6 years.