A New
Conception of Oral Potentially Malignant Disorders (PMDs) and Surgical
Management of PMDs
JojiSekine, D.D.S., Ph.D., FIBCSOMS,
Takahiro
Kanno, D.D.S., Ph.D.,
FIBCSOMS
Professor and Chairman,
Department of Oral and
Maxillofacial Surgery, Shimane University Faculty of Medicine
89-1 Enya-cho, Izumo, Shimane
693-8501, Japan
Tel.: +81-853-20-2301
Fax: +81-853-20-2299
Oral squamous cell carcinoma (OSCC)
comprises 92-95% of all oral cancers. OSCC sometimes show the
features of oral epithelial dysplasia (OED), numerous criteria exist for the
diagnosis of epithelial dysplasia, and there is not always a clear-cut
distinction between what presents a mild dysplasia consisting only of focal
dysplasia, which may represent carcinoma in situ (CIS). OED is
usually confirmed to a single tissue compartment and may progress to cancer,
but does not always do so. CIS or oral intraepithelial neoplasia (OIN) are
lesions that have the morphologic characteristics of cancer, including atypical
cells and dysplastic tissue organization, but are confirmed to one tissue
component and do not penetrate the basement membrane. Numerous criteria exist
for the diagnosis of OED, and there is not always a clear-cut distinction of what
represents mild dysplasia— consisting of only focal atypia, moderate dysplasia,
and severe dysplasia—which may present as OIN and CIS. Recently, such
borderline lesions are called potentially malignant disorders (PMDs). This
paper presents how we distinguish PMDs and other lesions as well as surgical
management of PMDs.
The
study included 114 patients (64 men, 50 women). All participants provided informed consent to
participate, following approval of the study protocol (approval no. 996; March
26, 2012) by the ethics committee of Shimane University Hospital. In all
patients, biopsy was done, which were formalin fixed, paraffin embedded. Histopathological diagnoses was done by
specialist of Pathology in our hospital. There were 67, 10, and 37
patients with OED, CIS, and OSCC, respectively. The expressions of Nucleus
accumbens-associated protein 1 (NAC1), cytokeratine 13 and 17, human papilloma
virus (HPV) 16, 18, and p16 were examined. Furthermore, c-mic, E-cadherin,
vimentin and Ki-67 were also used for distinguishing PMDs.
NAC1 labeling indices (Lis) cut-off
values which discriminated between OED and CIS/OSCC were 50%. NAC1 was also
available for distinguishing normal and OED with LIs cut-off value of 60%.OED
and OIN was distinguished using Ki-67 and c-mic, on the other hands, OIN and
OSCC was distinguished by the expression of E-cadherin and vimentin.
In
conclusion, PMDs (borderline lesions between normal and malignancy) are very
difficult to be diagnosed by routine HE staining. Our approach by various
immunohistochemical staining would be feasible to distinguish PMDs from normal
and OSCC. Regarding the management of PMDs, surgery should be indicated as some
PMDs show features of malignancy. More detailed study would be needed for
accurate diagnoses of PMDs.
