A Rare Presentation of Ameloblastic Carcinoma of the Sinus Cavity and Skull Base

Ameloblastic carcinoma of the mandible: a case report

BACKGROUND

Ameloblastic carcinoma is a malignant form of ameloblastoma and a very rare odontogenic tumor. We report a case of ameloblastic carcinoma that occurred after removal of a right-sided mandibular dental implant.

CASE PRESENTATION

A 72-year-old female patient visited her family dentist with a complaint of pain around a lower right implant placed 37 years previously. Although the dental implant was removed with the diagnosis of peri-implantitis, the patient experienced dullness of sensation in the lower lip and was followed up by her dentist, but after no improvement. She was referred to a highly specialized institution where she was diagnosed with osteomyelitis and treated the patient with medication; however, there was no improvement. In addition, granulation was observed in the same area leading to a suspicion of malignancy, and the patient was referred to our oral cancer center. The diagnosis of squamous cell carcinoma was made after a biopsy at our hospital. Under general anesthesia, the patient underwent mandibulectomy, right-sided neck dissection, free flap reconstruction with an anterolateral thigh flap, immediate reconstruction with a metal plate, and tracheostomy. Histological analysis of the resected specimen on hematoxylin and eosin staining showed structures reminiscent of enamel pulp and squamous epithelium in the center of the tumor. The tumor cells were highly atypical, with nuclear staining, hypertrophy, irregular nuclear size, and irregular nuclear shape, all of which were suggestive of cancer. Immunohistochemical analysis showed that Ki-67 was expressed in more than 80% of the targeted area, and the final diagnosis was primary ameloblastic carcinoma.

CONCLUSION

After reconstructive flap transplantation, occlusion was re-established using a maxillofacial prosthesis. The patient remained disease-free at the 1-year 3-month follow-up.

Ameloblastic Carcinoma of the Maxilla: A Rare Case Report and Review of Literature from 1948 to 2021

Ameloblastic carcinoma is a rare malignant neoplasm arising from the odontogenic epithelium. Ameloblastic carcinoma commonly occurs de novo affecting the posterior segments of the mandible. Presently, only less than 100 cases have been reported arising from the maxilla. We report a unique case of maxillary ameloblastic carcinoma in a 68-year-old male with a 5.6 cm positron emission tomography (PET) avid left maxillary sinus mass. The patient underwent a left maxillectomy which revealed hyperchromatic and pleomorphic tumor cells arranged in a nested and trabecular architecture. The tumor cells showed distinct peripheral palisading with reverse polarization. Areas of bone destruction, necrosis, lymphovascular and perineural invasions, as well as atypical mitoses, were identified. Immunohistochemically, the tumor cells were positive for keratin cocktail (AE1/AE3 and CAM 5.2), keratin 19, p40, and weakly positive for MDM2, while negative for calretinin. Molecular analysis revealed wild-type BRAF; however, alterations in CDKN2A/B, MTAP, RB1, SMARCA4, STK11, FGF12, SETD2, and TP53 were present. This histopathologic and molecular profile supported the diagnosis of ameloblastic carcinoma. There has been no evidence of disease recurrence or metastasis eleven months after the initial diagnosis.