Three soft tissue and bony swellings

Correct answer: A. Verruca vulgaris

• A. CORRECT as the exception. Verruca vulgaris is a SURFACE lesion — an HPV-driven papillary, exophytic growth with a rough, cauliflower-like or finger-like surface and a keratinised white appearance. It is not a submucosal NODULE. The question hinges on that distinction: everything else listed is a mass lying beneath intact mucosa.
• B. Traumatic fibroma is the commonest oral submucosal nodule of all, a reactive fibrous hyperplasia at a site of chronic irritation — the tongue included.
• C. Schwannoma is a benign nerve sheath tumour arising from Schwann cells, and the tongue is its commonest intra-oral site. It presents exactly as described — a slow-growing, firm, painless submucosal nodule.
• D. Granular cell tumour has a striking predilection for the tongue and is a classic submucosal nodule. Its histology is characteristic, with large granular eosinophilic cells and pseudoepitheliomatous hyperplasia of the overlying epithelium that can be mistaken for carcinoma.

Note: The clean division to carry into the exam: SURFACE papillary lesions are squamous papilloma, verruca vulgaris, condyloma acuminatum and verruciform xanthoma. SUBMUCOSAL nodules are fibroma, granular cell tumour, schwannoma, neurofibroma, lipoma and salivary gland lesions.

Correct answer: A. Nasopalatine duct (incisive canal) cyst

• A. CORRECT as the exception. The nasopalatine duct cyst is defined by its LOCATION — it arises from epithelial remnants in the incisive canal and therefore sits in the ANTERIOR MIDLINE palate, behind the central incisors, giving the classic heart-shaped radiolucency. A swelling of the POSTERIOR LATERAL palate is anatomically incompatible with it.
• B. Pleomorphic adenoma is the commonest minor salivary gland tumour and its favoured intra-oral site is precisely the posterior lateral hard palate, where minor glands are concentrated. It presents as a firm painless swelling.
• C. A palatal torus is a common developmental bony exostosis of the MIDLINE palate, though larger ones extend laterally, and it belongs in the differential of a hard palatal swelling.
• D. A palatal abscess from a non-vital lateral incisor or a palatal root of a premolar or molar is a routine cause of palatal swelling and must always be excluded by pulp testing.

Note: Always pulp-test the adjacent teeth before assuming a palatal swelling is developmental or neoplastic. An odontogenic abscess is the one that needs treating today.

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.