Pathology · patient case with 1 question
Swelling at the junction of the hard and soft palate
Patient: Female, 47 years old
Chief Complaint: “There is a lump toward the back of the roof of my mouth.”
Background: Noticed several months ago, slowly enlarging. No pain, no discharge, no numbness. Non-smoker.
Vital Signs: BP 124/76 mmHg · HR 72 bpm
Findings: A firm, dome-shaped swelling of the LEFT posterior hard palate extending to the junction with the soft palate, LATERAL to the midline. The overlying mucosa is intact and normal in colour. Adjacent teeth are vital and caries-free with no periapical change.
Question 1
Each of the following belongs in the differential diagnosis EXCEPT one. Which is the EXCEPTION?
Show answer and explanation
Correct answer: B. Nasopalatine duct cyst
- A. PLEOMORPHIC ADENOMA is the commonest minor salivary gland tumour, and the posterior lateral hard palate is its commonest intraoral site. A firm, slowly enlarging, painless submucosal swelling exactly there is the textbook presentation.
- B. CORRECT as the exception. The NASOPALATINE DUCT (incisive canal) CYST is defined by its LOCATION: it arises from remnants of the nasopalatine duct within the incisive canal, so it sits in the ANTERIOR MIDLINE between and above the maxillary central incisors, giving the classic heart-shaped or oval midline radiolucency. A lesion at the posterior hard-soft palate junction, lateral to the midline, cannot be one.
- C. A palatal abscess from a non-vital lateral incisor or the palatal root of a first molar is always worth excluding — though the vital, caries-free teeth and the absence of pain argue against it here.
- D. MUCOEPIDERMOID CARCINOMA is the commonest salivary MALIGNANCY and also favours the palate. It can look identical to a benign tumour early, which is precisely why every palatal swelling in this location is biopsied.
Note: Sort palatal swellings by SITE. Anterior MIDLINE: nasopalatine duct cyst, or a normal incisive foramen. Posterior midline or spanning the midline over bone: torus palatinus. POSTERIOR LATERAL, submucosal, firm: minor salivary gland tumour until proven otherwise, benign or malignant, and the odds of malignancy in a MINOR gland are far higher than in the parotid. Incisional biopsy is the next step — never enucleate a palatal salivary mass before you know what it is.