History of Present Illness
Bob is a 28 year-old-male who presents for a routine 6 month dental recall visit. On examination, a small yellow-tan papule is noted in the right floor of mouth. The patient is asymptomatic and completely unaware of the lesion. No mention of this lesion was made in the clinical notes from the patient’s last examination. Bimanual palpation of the floor of mouth reveals no other discrete masses. Clear saliva is easily expressed from the submandibular ducts. The patient does have mild exfoliative cheilitis secondary to a lip licking habit. The remainder of the oral examination is normal. An excisional biopsy is performed under local anesthesia.
Figure 1. Clinical image showing small yellow-tan papule in right floor of mouth.
The biopsy revealed a small submucosal cyst lined by thin stratified squamous epithelium with parakeratinizing luminal surface and abundant intraluminal keratin material. The wall of the cyst displayed a lymphocytic infiltrate with reactive germinal center formation. Serial sectioning showed that the cyst communicated with the surface mucosa (Figures 2 and 3).
Figure 2. Low power histologic image showing a submucosal cyst with adjacent reactive lymphoid tissue exhibiting germinal center formation.
Figure 3. High power histologic image of cyst wall lined by thin stratified squamous epithelium with a parakeratinizing luminal surface and associated mural lymphoid infiltrate. The cyst lumen is filled with keratin.