Another study conducted by Gill et al17 show pleomorphic adenoma as the commonest tumor 61.74% followed by warthin tumor 4.49%, hemangioma 2.11%, monomorphic adenoma 0.53% and myoepithelioma 0.26%, whereas the commonest malignant tumor was mucoepidermoid carcinoma 15.30% followed by adenoid cystic carcinoma 5.28%, carcinoma exploemorphic adenoma 1.32%, acinic cell carcinoma 1.00% and salivary duct carcinoma as 0.53%.
In a study conducted by Zaman et al13 the commonest tumor was pleomorphic adenoma 47.2% and monomorphic adenoma 7.5% was the second common tumor and myoepithelioma 5.6% was third in number.
Percentage Malignant neoplasms 3111 61.1 Adenoid cystic carcinoma 1966 38.6 Malignant lymphoma 306 6 Adenocarcinoma, NOS 274 5.4 Other malignancies (acinic cell carcinoma; undifferentiated carcinoma; small cell undifferentiated carcinoma; mucoepidermoid carcinoma, high grade/low grade; metastatic 565 11.1 carcinoma, NOS; sarcoma, NOS/spindle cell malignancy; and squamous cell carcinoma) Benign neoplasms 1717 33.7 Pleomorphic adenoma 1080 21.2 Monomorphic adenoma 526 10.3 Others (Warthin tumor, myoepithelioma, 111 2.2 and oncocytoma) Benign nonneoplastic lesions/normal/others 260 5.1 Lymphoepithelial lesions/lymphoepithelial cyst; sialoadenitis/granulomas; normal salivary gland; intraparotid lymph node; cyst, NOS Abbreviation: NOS, not otherwise specified.
(1) Most cases of ACC present with an asymptomatic mass that is usually indistinguishable from benign salivary gland tumors, such as pleomorphic or monomorphic adenomas, on clinical presentation.
. PLGAs are best differentiated from monomorphic adenomas
on the basis of a PLGA's infiltrative borders.
In this article, we describe an unusual case of a schwannoma that arose from the peripheral facial nerve and that was associated with a monomorphic adenoma
of the parotid.
(2) It is situated at one end of a biologic spectrum that includes pleomorphic adenomas and other monomorphic adenomas
Three false-negatives for malignancy (4%) were 2 monomorphic adenomas
diagnosed as high-grade muco-epidermoid carcinoma and acinic cell carcinoma, and a benign cyst diagnosed as acinic cell carcinoma.