Pathology · patient case question
Patient C's vestibular bump is excised. Histology shows normal lamellar bone with normal overlying mucosa and no inflammatory infiltrate. What is the diagnosis?
Patient case: Three soft tissue and bony swellings
Patient: Multiple patients presenting on the same clinic session
Chief complaint: Three separate patients, each with a painless swelling.
History: None of the three has relevant systemic disease.
Findings: Patient A: a firm submucosal nodule on the dorsum of the tongue. Patient B: a firm swelling of the posterior lateral hard palate. Patient C: a small hard bump in the anterior mandibular labial vestibule.
Show answer and explanation
Correct answer: D. An exostosis
- A. Peripheral ossifying fibroma is a reactive GINGIVAL lesion arising from the interdental papilla, showing a cellular fibrous proliferation with calcification and, usually, surface ulceration. It is soft tissue in origin, not a bony bump in the vestibule.
- B. Ossifying fibroma is a benign fibro-osseous NEOPLASM. Histology shows a cellular fibrous stroma containing bone trabeculae and cementum-like spherules — emphatically not normal bone.
- C. Multiple osteomas are a feature of Gardner syndrome, alongside supernumerary teeth, odontomas and colorectal polyps with high malignant potential. An osteoma is a benign tumour of bone rather than a simple exostosis, and a single vestibular bump in an otherwise well patient does not raise the syndrome.
- D. CORRECT. An exostosis is a localised, non-neoplastic overgrowth of NORMAL bone. Because it is simply bone in the wrong place, the histology is unremarkable — mature lamellar cortical bone with a normal marrow component and normal covering mucosa, no inflammation and no abnormal fibrous stroma. That entirely normal histology is the diagnostic finding, and it is what the question is testing.
Note: Exostoses and tori are removed only when they interfere with a prosthesis, are repeatedly traumatised and ulcerated, or obstruct function. Otherwise they are left alone.