Histopathological Aspects of the Prognostic Factors for Salivary Gland Cancers

Abstract

Salivary gland cancers (SGCs) are diagnosed using histopathological examination, which significantly contributes to their progression, including lymph node/distant metastasis or local recurrence. In the current World Health Organization (WHO) Classification of Head and Neck Tumors: Salivary Glands (5th edition), malignant and benign epithelial tumors are classified into 21 and 15 tumor types, respectively. All malignant tumors have the potential for lymph node/distant metastasis or local recurrence. In particular, mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), salivary duct carcinoma, salivary carcinoma, not otherwise specified (NOS, formerly known as adenocarcinoma, NOS), myoepithelial carcinoma, epithelial–myoepithelial carcinoma, and carcinoma ex pleomorphic adenoma (PA) are relatively prevalent. High-grade transformation is an important aspect of tumor progression in SGCs. MEC, AdCC, salivary carcinoma, and NOS have a distinct grading system; however, a universal histological grading system for SGCs has not yet been recommended. Conversely, PA is considered benign; nonetheless, it should be cautiously treated to avoid the development of metastasizing/recurrent PA. The aim of this review is to describe the current histopathological aspects of the prognostic factors for SGCs and discuss the genes or molecules used as diagnostic tools that might have treatment target potential in the future.

Adenoid cystic carcinoma of the retromolar pad region: A case report

“…Among the pathological subtypes of ACC, cribriform, tubular, and solid, the cribriform type is the most common, and the solid type is rare. But the latter has a higher rate of distant spread and lower rate of long-term survival [ 25 , 26 ].…”

Metastatic Myoepithelial Carcinoma Ex Pleomorphic Adenoma of the Sublingual Salivary Gland

“…There is limited research on the use of lenvatinib specifically for the treatment of MECA [9]. However, it may be considered a treatment option in certain cases, particularly if cancer has spread to other parts of the body and is not responding to other treatments [9,10].…”

PTEN Deregulation Mechanisms in Salivary Gland Carcinomas

“…In contrast, SDCs represent high-grade malignancies characterized by local and distant metastases that appear as rapidly formed neck masses (28) Besides the abovementioned main SGC histotypes, there are also other less frequently observed including clear-cell carcinoma (CCC), basal cell adenocarcinoma (BCAD), acinic-cell carcinoma (ACC), cystadenocarcinoma (CADC), polymorphous adenocarcinoma (PADC), sebaceous adenocarcinoma (SADC), secretory carcinoma (CEC), mucinous adenocarcinoma (MADC), and sebaceous lymphadenocarcinoma (SLADC) (29). Furthermore, more ''exotic' and rare with increased biological aggressiveness carcinoma sub-types include epithelial-myoepithelial carcinoma (EMC), carcinoma ex pleomorphic adenoma (CexPAD), intra-ductal carcinoma (INDC), carcinosarcoma (CSC), squamous cell carcinoma (SCC), anaplastic small cell carcinoma (ASCC), and finally undifferentiated carcinomas (UNC) (30).…”