Role of intraoral ultrasound in evaluating tumor depth and thickness: case report

Aim: The management of patients affected by early stage (T1-T2) of oral squamous cell carcinoma (OSCC) clinically N0 is still controversial. In fact, even if in 30% of cases the post surgical follow up has shown the presence of occult metastases in latero-cervical lymph-nodes; on the other hand, in 70% of patients with OSCC clinically and radiographically N0, the selective latero-cervical lymph-nodes dissection proved to be an overtreatment. Tumor depth of invasion (DOI) is the extent of tumor growth beyond lamina propria; it is different from tumor thickness that includes exophytic and endophytic growth. The Literature considers DOI as the most important prognostic factor in prediction of local recurrence and occult lymph-node metastases; nevertheless a precise cut-off value of DOI, indicating the need of a neck selective surgical treatment is still uncertain. Moreover, in OSCC cases with DOI≤4mm or close to implant-prosthetic rehabilitations, Computed Tomography and Magnetic Resonance (MRI) are unable to detect the tumor. The question is whether an alternative diagnostic method could detect reliable values of DOI, in order to provide a preoperative indication to latero-cervical lymph nodes selective dissection in stage cT1-T2 N0 M0 patients. Ultrasonography is a non-invasive, radiation free, easy-to-use and inexpensive exam used in oral pathology for the diagnosis of: mucoceles, salivary glands diseases, lipomas and vascular lesions. This case report describes an intraoral ultrasound (IUS) application in the evaluation of oral cancer parameters that influence therapy and prognosis and the proposal for its inclusion in OSCC diagnostic flowchart. Methods: A 80-year-old male patient with negative history for risk factors associated with oral cancer, presents an OSCC on the left side of tongue. The patient brought at the first visit, an head and neck MRI with/without constrast agent. The IUS of the lesion was performed by E-CUBE 15 EX scanner (Alpinion, Seoul, Korea) with linear intraoperative “hockey stick” probe with 8-17 transducer MHz, while the neck ultrasonography was performed by a 3-12 MHz transcutaneous linear probe at the Operational Simple Unit of Diagnostic and Ultrasonographic Innovations. The DOI was calculated by intraoral ultrasound device and it was matched with the correspondent parameter derived by post-operative histological specimen examination and with the tumor total thickness measured also by the IUS. The procedure was done to investigate a correlation between the two types of growth. It was also verified whether the aspecific lymphadenopathy detected by ultrasound corresponded to lymph-node metastasis, then confirmed by TNM. Result: The DOI calculated by the IUS was 4mm while it was 3mm at the histological examination. So the IUS seemed not to underestimate DOI. MRI reported one pathological lymph node in left laterocervical region appearing as a non-specific lymphadenopathy on neck ultrasonography; this has been confirmed as metastasis by the TNM. The total histological thickness was 5mm. Conclusion: The IUS seems not to underestimate DOI, then it could be considered a diagnostic support for OSCC surgery and especially for targeting those patients who need selective treatment of the neck. Difference between DOI and thickness 429 Abstracts of poster presentations © ARIESDUE June 2019; 11(2) values confirm that thickness could be a misleading parameter in predicting disease biological behavior. Ultrasonography of neck lymph nodes, performed contemporarily to IUS, could be used as a first step to formulate a diagnostic suspicion of nodal metastasis in OSCC N0 clinical staged patients.