1. SYNCHRONOUS BILATERAL MULTIFOCAL CANALICULAR ADENOMA: A CASE REPORT OF AN UNUSUAL FINDING Gelsomina Mansueto, Jessica Falleti, Chiara Mignogna, Gaetano De Rosa Dipartimento di Scienze Biomorfologiche e Funzionali, Sezione di Anatomia Patologica e Citopatologia, Università Federico II, Napoli

2. A 78 years old woman presented with a bilateral synchronous swelling both in the right and left nose labial wrinkle occurring about 6 years ago and slowly growing. Clinical examination showed, on the right side, two nodules of 4 and 2 cm of maximum diameter, while on the left one another two nodular lesions, both of 1 cm: lesions were mobile at palpation, hard, not painful, with sharp border and covered with intact skin.

3. The ultra sonogram study showed in the both left (Fig.1A) and right (Fig.1B) nose labial wrinkle, multiple non-homogeneous isoechoic nodules, with peri- and intra-lesional vascularization at colour-Doppler.

4. The patient has been undergone to a surgical excision of all masses through an intra-oral approach. On the left side one of the nodules was adherent to Stenone’s duct, so it needed to be first sectioned and then anastomosed to mucosa.

5. Histology showed a neoplastic proliferation constituted of double rows of columnar epithelial cells that form branching and interconnecting cords and narrow channels (“canaliculi”) in a very loose stroma (Fig.2).

6. Lining epithelial cells varied from cuboidal to tall columnar with amphophilic or eosinophilic cytoplasm and round nuclei; pleomorphism or pleochromatism and mitosis were absent (Fig.3).

7. benign neoplasms are the most frequent tumors of minor salivary glands and, among these, canalicular adenoma is second to pleomorphic adenoma several cases with multifocal canalicular adenoma are described in literature: most common site is upper lip and buccal mucosa none case described a synchronous and bilateral occurrence of a multifocal canalicular adenoma

8. multifocal presence of canalicular adenoma could be explained with small tumor island foci adjacent to the main lesion but also within capsule or in around normal salivary tissue differential diagnosis should include some benign lesion like multiple epidermal and sebaceous cysts, adnexal neoplasm’s and minor salivary glands pathologies like mucocele or neoplasm’s.

9. Histologically it must be distinct by a basal cell adenoma and a polymorphous low grade adenocarcinoma: an immunohistochemical assay could be performed, using a panel with cytokeratins 13 and 14, vimentin and alpha smooth actin

10. Clinical behaviour is generally benign with a low tendency to recurrence and no locally aggressive Our case recurred after one year: we retain that this could been explained both with multiple small tumoral foci within surrounding tissues (multifocal tumor ), both with intra-oral surgical approach that presented much more technical difficulties than to extra-oral approach, especially when, on surgery, one lesion appeared adherent to left Stenone’s duct.

11. So we conclude that canalicular adenoma is a benign neoplasm, can be find also in nose labial wrinkle, can be both synchronous and multifocal and bilateral, a surgical excision is an appropriate approach, but an accurate histological study is necessary to exclude a malignancy, accompanied by a long follow-up

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