Oral premalignant lesions: from the pathological viewpoint

Abstract

Under the widely used World Health Organization (WHO) classification for the pathological diagnosis of oral premalignant lesions, dysplasia, which is graded as mild, moderate or severe, and carcinoma in situ (CIS), which is a non-invasive carcinoma, are classified as precursor lesions of oral squamous cell carcinoma. Since the first edition (Wahi et al. International histological classification of tumours no. 4, WHO, Geneva, 1971), the criterion for CIS--that all epithelial layers are replaced by atypical cells--has remained unchanged. However, this dysplasia-carcinoma sequence theory was introduced from the viewpoint of pathological changes in the uterine cervix: in contrast, almost all premalignant lesions and CIS of the oral mucosa show superficial maturation and differentiation. Based on this recognition, the squamous intraepithelial neoplasia (SIN) classification and Ljubljana classification were included in WHO's latest edition published in 2005. Although the WHO classification is commonly used in Japan, recent developments in oral oncology have promoted modifications of the classification used in this country. In 2005, the Working Group of the Japan Society for Oral Tumours advocated iodine staining and proposed a modified SIN system, and in 2007, the Working Committee of the Japanese Society for Oral Pathology (JSOP) reported a new CIS (JSOP) definition that included differentiated-type CIS. In 2010, based on these studies, a new entity--oral intraepithelial neoplasia (OIN)--was included in the first edition of General Rules for Clinical and Pathological Studies on Oral Cancer. In this review, we focus on the OIN/CIS (JSOP) new classification of premalignant lesions in oral mucosa, which further advances the concept of SIN.

Loss of DLC1 is an independent prognostic factor in patients with oral squamous cell carcinoma

“…However, screening for head and neck cancer in premalignant stages and identifying oral premalignant lesions (dysplasia) at high risk of transformation is currently unpredictable. [5][6][7][8]41,42 Furthermore, the histological diagnosis of dysplasia can be subjective and is thus prone to considerable variations in interpretations among pathologists. Thus, molecular biomarkers capable of identifying the subset of lesions likely to progress to cancer are required to eliminate this clinical diagnostic dilemma.…”

An Update on Precancerous Lesions of Oral Cavity

“…The accelerated pace of cell division noted at the earlier stages of transformation as a part of adaptive response (to replace the damaged cell pool) is, in a way, facilitative of the accumulation of further genetic damage, thereby driving the cells further along the path of transformation. [13,14] Clinical classification: [15]  o Phase IV: Erythroleukoplakia -poor prognosis. [10] The current "gold standard" for predicting the malignant potential of premalignant lesions is the presence and degree of dysplasia.…”

Current Views and Perspectives on Classification of Squamous Intraepithelial Lesions of the Head and Neck

“…The clinical appearance of non-homogeneous or speckled OL may correlate with the likelihood that the lesion will show epithelial changes or malignant transformation. In a study by Silverman and co-workers, the overall malignant Table 1 Modified review of Izumo [14] presenting six classifications of oral and laryngeal precursor lesions [2,7,[15][16][17] WHO-DC World Health Organization dysplasia system; CIS carcinoma in situ; SIN squamous intraepithelial neoplasia; LC Ljubljana classification; SIL squamous intraepithelial lesions; OIN oral intraepithelial neoplasia; OED oral epithelial dysplasia; JSOP Japanese Society for Oral Pathology [22]. Compared to OL, oral erythroplakia has significantly worse biological behavior, with up to 50 % of malignant transformation [23].…”

“…Numerous articles have reported attempts to evaluate the reliability and inter-observer agreement of these grading systems for oral and laryngeal SILs [6][7][8][9][10][11][12][13]. Some of them have also compared WHO grading systems with new proposals, such as a binary grading system and other classifications for oral lesions or, more widely, for the whole head and neck region (Table 1) [2,7,9,[15][16][17].…”