Bone alterations in head and neck pleomorphic adenoma: Scoping review.

Objectives: Bone destruction adjacent to salivary gland tumors has been regarded as an indirect sign of malignancy. This scoping review explores possible bone changes due to head and neck pleomorphic adenoma and identifies risk factors for bone destruction.

Methods: Articles on bone alterations in head and neck pleomorphic adenoma were searched online using PubMed, Scopus and Scholar, according to PRISMA-ScR guidelines. Only histopathologically confirmed pleomorphic adenomas were included. Extracted data were age, gender, location and size of tumor, duration of symptoms, type of bone erosion and recurrency status.

Results: The search resulted in 145 pleomorphic adenomas with adjacent bone alterations. The majority caused expansile bone changes, such as cortex erosion (61.4%) and scalloping (31.0%). Extensive bone destruction was reported in 11 cases (full thickness erosion in 3.4% and bone marrow invasion in 4.1%). Significant risk factors for aggressive bone destruction were tumor size and duration of symptoms (OR = 1.08; 95% CI 1.02-1.14 and OR = 1.03; 95% CI 1.00-1.05).

Conclusions: Although mostly bone erosion or scalloping is observed, larger or longstanding pleomorphic adenomas have the capacity of developing more extensive bone destruction, without malignant transformation. However, bone destruction is very rare in pleomorphic adenoma and more likely indicates the presence of malignancy.