Primary Pulmonary Ameloblastoma: First Case Series With Clinicopathologic and Genomic Analysis

Area of Science:

• Oncology
• Pathology
• Genetics

Background:

• Ameloblastomas are aggressive odontogenic tumors typically found in the jaw.
• Primary pulmonary ameloblastomas have not been previously documented.
• BRAF V600E mutations are common in gnathic ameloblastomas.

Purpose of the Study:

• To describe the clinicopathologic and molecular features of primary pulmonary ameloblastomas.
• To confirm the presence of BRAF V600E mutations in these lung tumors.
• To differentiate pulmonary ameloblastomas from other lung neoplasms and rule out gnathic origins.

Main Methods:

• Clinicopathologic analysis of 3 pulmonary neoplasms with ameloblastoma features.
• Immunohistochemical (IHC) staining for BRAF V600E.
• Molecular assays, including next-generation sequencing, to confirm BRAF V600E mutations.
• Exclusion of occult gnathic primary tumors via clinical examination and dental radiography.

Main Results:

• Three solitary, peribronchial lung masses (5.4-7.3 cm) exhibited ameloblastoma histology.
• Tumors showed a stellate reticulum-like component and palisaded columnar cells.
• All cases were positive for BRAF V600E by IHC and molecular testing.
• Pneumocyte hyperplasia was identified as entrapment, not a distinct neoplastic component.

Conclusions:

• This series represents the first documented cases of primary pulmonary ameloblastomas.
• These tumors share identical histologic and molecular features with gnathic ameloblastomas.
• The findings expand the known spectrum of ameloblastoma presentation and raise questions about their histogenesis.