Unilateral widening of the inferior alveolar nerve canal: a rare anatomic variant mimicking disease

Unusual metastatic presentations of a primary right parapharyngeal acinic cell adenocarcinoma

Acinic cell adenocarcinoma (ACA) is a malignant epithelial neoplasm of the salivary glands. The patient reported herein presented with an unusual case of a metastatic ACA originating from the right parapharyngeal region, which eventually metastasized to the ipsilateral cavernous sinus and the contralateral mandibular ramus. The trigeminal nerve may have served as a channel for the spread of the cancer from the right parapharyngeal region to the cavernous sinus, and subsequently to the left mandibular ramus. The widening of the left inferior alveolar nerve canal was an early sign of metastasis in this case.

Common conditions associated with mandibular canal widening: A literature review

Purpose

The aim of this study was to review the common conditions associated with mandibular canal widening.

Materials and Methods

General search engines and specialized databases including Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus were used to find relevant studies by using the following keywords: “mandibular canal,” “alveolar canal,” “inferior alveolar nerve canal,” “inferior dental canal,” “inferior mandibular canal,” “widening,” “enlargement,” “distension,” “expansion,” and “dilation.”

Results

In total, 130 articles were found, of which 80 were broadly relevant to the topic. We ultimately included 38 articles that were closely related to the topic of interest. When the data were compiled, the following 7 lesions were found to have a relationship with mandibular canal widening: non-Hodgkin lymphoma, osteosarcoma, schwannoma, neurofibroma, vascular malformation/hemangioma, multiple endocrine neoplasia syndromes, and perineural spreading or invasion.

Conclusion

When clinicians encounter a lesion associated with mandibular canal widening, they should immediately consider these entities in the differential diagnosis. Doing so will help dentists make more accurate diagnoses and develop better treatment plans based on patients' radiographs.

Radiolucent lesions of the mandible: a pattern-based approach to diagnosis

Objectives

Radiolucent mandibular lesions seen on panoramic radiographs develop from both odontogenic and non-odontogenic structures. They represent a broad spectrum of lesions with a varying degree of malignant potential. The purpose of this review is to illustrate the characteristic imaging findings—as well as the clinical and histological features—of common and uncommon radiolucent lesions of the mandible.

Methods

This review article is based on the retrospective evaluation of 11,725 panoramic radiographs seen in our institution during the past 6 years. It provides a comprehensive, practical approach to the radiological interpretation of radiolucent lesions of the mandible. To facilitate the diagnostic approach, we have classified radiolucent lesions into two groups: lesions with well-defined borders and those with ill-defined borders.

Results

Lesion prevalence, age of manifestation, location within the mandible, relationship to dental structures, effect on adjacent structures and characteristic findings at computed tomography (CT), cone beam CT (CBCT) and magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) are discussed. Pitfalls including malignant lesions mimicking benign disease and pseudo-lesions are equally addressed.

Conclusion

Knowledge of the characteristic imaging features of radiolucent mandibular lesions narrows the differential diagnosis and is crucial for the identification of those lesions, where biopsy is indicated for definitive histology.

Teaching points

• Panoramic X-rays, CT and MRI are essential for the work-up of radiolucent mandibular lesions.

• Lesion borders, location within the mandible, relationship to dental structures and tissue characteristics on cross-sectional imaging are indispensable to narrow the differential diagnosis.

• High-resolution CT and CBCT play a major role for the assessment of lesion margins and their relationship to important anatomic structures, such as the inferior alveolar nerve.

• Although most radiolucent lesions with well-defined sclerotic borders are benign, MRI may reveal clinically unsuspected malignant disease.