Solid variant of adenoid cystic carcinoma of oral cavity: A diagnostic difficulty in

Introduction: Adenoid cystic carcinoma (ACC) is a malignant tumor affecting mainly the salivary glands. It can also occur in other sites like breast and skin. It is important to diagnose adenoid cystic carcinoma at its early stage because this tumor is well known for its local recurrence and distant metastasis. This tumor accounts for about 1% of all head and neck malignancies and 6-10% of all salivary gland neoplasms. Adenoid cystic carcinoma occurs in any salivary gland site, but approximately 50-60% develop within minor salivary gland especially palate. The tumor is seen to arise from the pluripotent stem cell which gives rise to ductal epithelial and myoepithelial cells. Three patterns occur in ACC namely cribriform, tubular and solid. The cribriform pattern is the most common form and the solid pattern is the least common. However, in most cases combination of two or more patterns are seen. The solid variant of ACC has significant morphological and immunohistochemical overlap with a large range of tumors including others carcinoma and sarcoma. Case Report: In this study, we describe three cases of oral cavity lesions with different clinical presentations. Histopathological examination was done and a diagnosis was made. Immunohistochemistry was further done to support the diagnosis. Discussion: Solid variant of ACC was diagnosed on histopathological examination of all three cases. Solid variant of ACC may be misinterpreted for many other benign and malignant tumors, in oral cavity, because cribriform pattern which is seen in most cases of ACC is lacking in this variant. These three cases are presented here because of rarity and difficulties in diagnosis of this pattern of ACC exist in microscopic examination. These patients need to be treated with intensive therapy to avoid recurrence and further spread.