Gingival mucinous adenocarcinoma of a minor salivary gland.

Background: A 47-year-old male non-smoker with a history of psoriasis sought a consultation because of a painless, hard-on-palpation, 1-cm exophytic lesion with a smooth and speckled surface located on the hard palate adjacent to tooth #12. The radiologic examination revealed no bone destruction. The lesion was clinically diagnosed as a fibrous hyperplasia or chronic pyogenic granuloma.

Methods: The lesion was surgically removed, fixed in 10% neutral buffered formalin for 24 hours, and, following common practice, embedded in paraffin. Sections, 4 mum thick, were stained with hematoxylin and eosin, periodic acid-Schiff, and alcian blue, pH 2.5. An immunohistochemical study was also performed.

Results: A definitive diagnosis of a mucinous adenocarcinoma (MAC), a very rare, high-grade malignancy tumor that more frequently appears in the elderly, was made. With the definitive diagnosis of an MAC of the palate, the upper-left premolars were extracted using a box osteotomy, and the surgical wound was reconstructed with a Bichat fat-pad flap. After a 6-month follow-up, no recurrence or cervical metastases were identified.

Conclusions: An MAC of a minor salivary gland may arise as a gingival exophytic lesion with a clinical appearance similar to a pyogenic granuloma. The existence of a light speckled pattern on the surface of the lesion indicates that an incisional biopsy is needed before surgical treatment to make possible a definitive diagnosis. To avoid delays in diagnosis and erroneous clinical approaches to exophytic gingival lesions, periodontists and practitioners should routinely perform a pathologic analysis to confirm the diagnosis when dealing with these kinds of lesions.