Application of direct oral microscopy in evaluating mucosal margins around invasive oral squamous cell carcinoma

Abstract

Introduction: Direct oral microscopy constitutes a novel, non-invasive diagnostic technique, which aids clinical examination of the oral cavity. The oral mucosa is examined at multiple magnifications and features such as sub-epithelial mucosal vessels, surface patterns, colour tone, transparency and the exact demarcation of mucosal lesions are estimated. The incidence of oral squamous cell carcinoma (OSCC) oscillates between 1.9% and 3.5%, which makes it the eighth most common carcinoma occurring around the world and in Poland. The 5-year survival rates oscillate between 20% and 30%.

Aim: The aim of the study was to evaluate clinically unchanged mucosal margins around OSCC by direct oral microscopy. The authors approached the question whether the borders of mucosal margins around OSCC established via direct oral microscopy differ from those established based on clinical examination.

Material and methods: Fifteen patients diagnosed with OSCC were enrolled. Patients were first clinically examined to evaluate the extent of the tumour and to plan resection margins. Eventually, direct oral microscopy was performed to establish the width of the subclinically unchanged mucosal margins based on a standard picture of healthy oral mucosae, followed by comparison with those established by clinical evaluation.

Results: Histopathologic results of biopsies from areas indicated by direct oral microscopy revealed dysplasia in 86.7% of patients, whereas biopsies from areas indicated by clinical examination revealed dysplasia only in 40% of individuals, resulting in the need for widening of mucosal margins.

Conclusions: Direct oral microscopy enables detection of dysplasia within clinically unaltered mucosal margins around OSCC, which results in more precise establishing of resection boundaries, contributing to improvement of resection totality.

Keywords: direct microscopy; oral cavity; squamous cell carcinoma.

Figure 1

The arrows indicate punctation capillaries within clinically unchanged oral marginal mucosae around lingual cancer, seen with a green filter (magnification 15×)

Figure 2

Branched pathologic vessels of the first degree according to Madej (arrows) visible within the margins of invasive buccal cancer (magnification 30×)

Figure 3

Smooth surface of marginal mucosae around invasive oral floor cancer. The moisture and gloss of the surface are similar to healthy oral mucosae (magnification 30×)

Figure 4

Mandibular gingival cancer (arrow). Rosy colour of marginal oral mucosae (magnification 30×)

Figure 5

Lateral tongue cancer developed on the basis of long-term leucoplakia. The arrow indicates the redness of the marginal mucosa (magnification 7.5×)

Figure 6

Total transparency of marginal mucosa around invasive buccal cancer. Sub-epithelial capillaries (arrow) visible without applying a green filter (magnification 15×)

Figure 7

Partial transparency of marginal mucosa around invasive cancer of the ventral tongue. Sub-epithelial capillaries (arrow) within marginal mucosa as seen with a green filter (magnification 30×)

Figure 8

Local recurrence of lateral tongue cancer. Irregular boundaries of marginal mucosa around the tumour in the lower portion (arrow). Two foci of abnormal redness in the mucosa around the tumour (arrowheads) project to an unclear extent into the unaltered lingual mucosa. The violet line indicates the extent of resection (magnification 15×)

Figure 9

Lateral tongue cancer. A biopsy obtained from the site indicated by the black arrow revealed moderate dysplasia, while under clinical examination the site seemed healthy. Magnification 15× depicts focal redness of the mucosa in the biopsy site (grey arrow)

Figure 10

Numerous small punctation capillaries seen in the lower margins of a lesion diagnosed as homogenous leucoplakia, seen with a green filter (magnification 15×)

Figure 11

Extensively branched, pathologic vessels of the first degree according to Madej (arrows), seen within the mucosal margins around oral floor cancer (magnification 30×)

Figure 12

Arrows indicate sub-epithelial punctation capillaries within marginal mucosae around lateral tongue cancer (magnification 15×)