Primary intraosseous ACC of mandible of possible salivary origin: A rare clinical entity

Diagnostic approach for the rare anterior variant of mandibular bone depression often misdiagnosed as tumorous lesions

Background/purpose

This study analyzed the clinical and imaging features of lingual mandibular bone depression (LMBD) in the anterior mandible, aiming to prevent misdiagnosis and unnecessary surgical procedures.

Materials and methods

The patients who visited a university dental hospital for painless radiolucency in the anterior mandible from January 2010 to December 2022 were retrospectively reviewed. Twelve cases of LMBD in the anterior mandible that are confirmed by biopsy or long-term follow-up were identified. Two oral and maxillofacial radiologists evaluated the imaging features. Additionally, 12 cases were manually collected from case reports published between 2001 and 2022. Clinical and histopathologic data were obtained from both groups and clinical information were compared using Fisher's exact test.

Results

The clinical information of the patients and that from the case reports showed no statistically significant differences, except for the clinical impression (P = 0.005). The imaging features of anterior LMBD included the absence of lingual cortical expansion and soft tissue bulging, a mostly round cortical border, and muscle-level attenuation, as observed on multidetector computed tomography (MDCT). Occasionally, the progression of LMBD led to thinning of the labial cortex.

Conclusion

If non-specific clinical features are present, MDCT is recommended to distinguish anterior LMBD from tumorous lesions that require surgical intervention.

A torus-like sublingual adenoid cystic carcinoma in a 35-year-old male: Review of literature and case report

Key Clinical Message

The case report describes an adenoid cystic carcinoma occurring at a rare location and the diagnostic pathway. Swellings of the floor of the mouth, whether painful or without subjective symptoms and regardless of consistency, should be taken seriously.

Abstract

Adenoid cystic carcinoma (ADCC) of the sublingual salivary gland only accounts for 2% of all ADCCs. In this study, we report a rare case of ADCC with sublingual salivary gland origin in a 35-year-old man and a comprehensive review of articles published over the past 62 years.

Carcinoma ex-pleomorphic adenoma of mandible: A case report and review of literature

Introduction and importance

The most common benign neoplasm of major and minor salivary glands is pleomorphic adenoma (PA). Around 80 % of all parotid neoplasms are pleomorphic adenomas, while 44–68 % and 38–43 % tumors were pleomorphic adenomas of submandibular and minor salivary gland tumors. PA has been reported in a variety of anatomic locations including true intraosseous mandibular tumor, external ear canal, TMJ region, lacrimal gland, epiglottis, larynx and nasopharynx, breast, lung, esophagus, sinonasal and skull base and trachea.

Pleomorphic adenoma has a tendency to transform into a number of malignancies; carcinoma ex-pleomorphic adenoma, carcinosarcoma or metastasizing pleomorphic adenoma. Pleomorphic adenomas most commonly transform into carcinoma ex-pleomorphic adenoma (CEPA).

Case presentation

A 30-year-old male presented with the primary complaint of a long-standing swelling at his right mandibular region for past 18 months. On intra oral examination, there was a non-healing alveolar socket of right lower 3rd molar tooth while rest of the dentition and mucosal surfaces were normal. On extra oral examination, mouth opening was adequate with intact lower border of the mandible and no palpable lymph nodes in the neck. Initial biopsy of lesion showed pleomorphic adenoma, but later the lesion came out to be carcinoma ex-pleomorphic adenoma, for which he underwent segmental mandibulectomy and free fibular flap.

Clinical discussion

The prevalence of CEPA transformation from pleomorphic adenoma is 1.5 % within the first 5 years of diagnosis, going up to 10 % after 15 years. The true rate of malignant transformation in recurrent pleomorphic adenoma is reported to be 3.3 %. We report a case of an intra-osseous carcinoma ex pleomorphic adenoma (CEPA) of the mandible. It is thought that ectopic entrapment of salivary tissue or developmentally included embryonic remnants of submandibular glands within recesses or lacunae of the mandibular bone could explain the intraosseous origin of a salivary gland tumor in the mandible. Since carcinoma ex pleomorphic adenoma (CEPA) arises from primary or recurrent pleomorphic adenoma, therefore it poses a diagnostic challenge for histopathologists. The radiographic picture of primary tumor/recurrence can mimic odontogenic cyst/tumor; therefore, a sinister disease process should always be kept in mind. In the post operative period, regular follow up is required to treat any recurrence. The recurrence rate for such disease has not been documented.

Conclusion

Intra osseous CEPA is a very rare tumor. Intra bony tumors which rapidly increase in size have signs and symptoms of nerve involvement and cause bony destruction should have a high suspicion of index of malignancy. Therefore, biopsy must be correlated with clinical and radiological features. Regular follow up is necessary to detect any recurrence promptly.

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Carcinoma expleomorphic adenoma is a salivary gland tumor that can rarely occur in unique sites like mandible.

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Pleomorphic adenoma can co-exist with carcinoma expleomorphic adenoma which may give different biopsy results.

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Clinical and radiological correlation with tissue diagnosis is important.

A case of sublingual adenoid cystic carcinoma involving the mandible presenting as a "skip lesion"

Adenoid cystic carcinoma (ACC) is a slowly growing malignant neoplasm with a propensity for perineural invasion. Microscopic invasion of ACC often prevents its detection on computed tomography (CT) or magnetic resonance imaging (MRI). We herein report a rare case of sublingual ACC presenting as a "skip lesion" that rapidly infiltrated the mandible after tumor resection. A 64-year-old man presented to Okayama University Hospital with an 18-month history of swelling in the right floor of the mouth. Clinical examination displayed an ulcerated swollen mass in that region. An enhanced mass was detected in the right sublingual space on CT and MRI. Bone surface erosion was observed at the inferior border of the mandible, but continuity with the sublingual mass or mass around that lesion was not detected by imaging. Sublingual tumor resection and selective neck dissection were performed by the pull-through method. Histopathologically, the surgical margins were free of cancer cells, and the tumor was diagnosed as ACC. Continuity with the sublingual mass and mandibular bone was not detected intraoperatively. However, marked bone resorption was detected in the anterior mandible 3 months after the operation. Biopsy was performed, and the findings indicated the same histological type of sublingual ACC. This case suggests that a malignant tumor close to the jaw bone requires the clinician to consider the possibility of bone invasion and to observe a wide region surrounding the tumor using imaging examination.

[Central adenoid cystic carcinoma of the mandible: a case report]

Central malignant salivary gland tumor of the mandible is rarely observed with adenoid cystic carcinoma, which only comprises a small proportion of cancer patients. In this study, a patient with central adenoid cystic carcinoma of the mandible is presented, and relevant literature is reviewed.