Acinic cell carcinoma on the lower lip resembling a mucocele

Abstract

A 64-year-old woman presented with a 2-week history of an asymptomatic mass involving the lower lip. Histopathological examination showed a well-circumscribed tumour composed of many lobules separated by thin, fibrous connective tissue. Individual lobules were composed of round or polyhedral tumour cells, which had a characteristic finely granular and vacuolated cytoplasm and eccentric hyperchromatic nuclei. Positive staining was observed with Periodic acid-Shiff, and immunohistochemistry for cytokeratin, alpha-1 antitrypsin, and S-100 protein resulting in a final diagnosis of acinic cell carcinoma. Acinic cell carcinoma represents a well-established, although uncommon, entity in the classification of neoplasms of salivary gland origin. The parotid salivary gland is the most frequent site of acinic cell carcinoma, whereas the lip is a particularly unusual site. The unusual presentation of this tumour may lead to confusion with a mucocele. Given these findings, we suggest that acinic cell carcinoma should be considered in the differential diagnosis of any mucocele-like mass on the lower lip.

Nasal Acinic Cell Carcinoma in a Cat

“…They may be positive for S-100 and cytokeratin, as in the present case. 4 Additionally, positivity for a-amylase and a-antitrypsin has been described, but none of these markers have been proved specific. 4 Furthermore, there is a high variation in intensity and distribution of positive staining, not only between tumors but also within the same tumor.…”

Incidental Discovery of Acinic Cell Carcinoma of the Oral Mucosa with Metachronous Adenoid Cystic Carcinoma of the Upper Lip

“…Involvement of the minor salivary glands is uncommon and intraoral ACCs generally affect the oral mucosa, lips and palate (Triantafillidou et al; Omlie & Koutlas). Individual ACCs found in oral mucosa can often be confused with mucoceles, especially in cases involving the lower lip (Cho et al, 2005). In the present case, the clinical hypothesis of mucocele was raised because of its clinical appearance and the recurrent episodes of increasing and decreasing size of the lesion reported by the patient.…”

Acinic cell carcinoma of the submandibular salivary gland presenting as a large cyst

“…This tumour most commonly occurs in the parotid gland, with cases also reported in submandibular, sublingual, and minor salivary glands 1,8 . Acinic cell carcinoma constitutes about 13-19% of parotid gland malignant neoplasms 1,4 . Bilateral tumours and those arising from entopic salivary gland tissue have been reported 4,5 .…”

“…2 Encapsulation may be incomplete with a variable degree of invasion of adjacent tissues 1 . Histopathologic features are often markedly similar to normal serous cells, which has led some investigators to believe that the tumours are derived from acinar cells 1 . The presence of intercalated duct-type cells and the considerable variety of histomorphologic patterns suggest the origin to be from the more pluripotential duct cells, as is the case for serous cells in normal gland development 4 .…”