Ademar Takahama

Time-resolved fluorescence spectroscopy for clinical diagnosis of actinic cheilitis.

Actinic cheilitis is a potentially malignant disorder of the lips. Its first cause is believed to be UV sun radiation. The lesion is highly heterogeneous, making the choice of area to be biopsied difficult. This study exploits the capabilities of time-resolved fluorescence spectroscopy for the identification of the most representative area to be biopsied. A preliminary study was performed on fourteen patients. A classification algorithm was used on data acquired on nine different biopsies. The algorithm discriminated between absent, mild, and moderate dysplasia with a sensitivity of 92.9%, 90.0%, and 80.0%, respectively. The false positive rate for healthy tissue (specificity) was 88.8%.

Chondrosarcoma of the maxilla: Report of two cases with different behaviours

Head and neck chondrosarcomas are rare and potentially lethal tumours, which are even more uncommon in the head and neck region. The diagnosis of chondrosarcoma is based on the histopathological pattern of malignant chondroid tissue proliferation. The grade of malignancy and the histological surgical margins are some of the most important prognostic factors for this group of tumour. In the present report we described two cases of chondrosarcoma affecting the maxilla, which presented different behaviours. The first patient, with a high-grade tumour, died of local recurrence and the second patient, with a low-grade tumour, is alive and free of disease 60 months after the treatment. These two cases emphasize the importance of histological tumour grade and appropriate treatment for the prognosis.

Automated algorithm for actinic cheilitis diagnosis by wide-field fluorescence imaging

Abstract. Actinic cheilitis (AC) is a disease caused by prolonged and cumulative sun exposure that mostly affects the lower lip, which can progress to a lip squamous cell carcinoma. Routine diagnosis relies on clinician experience and training. We investigated the diagnostic efficacy of wide-field fluorescence imaging coupled to an automated algorithm for AC recognition. Fluorescence images were acquired from 57 patients with confirmed AC and 46 normal volunteers. Three different algorithms were employed: two based on the emission characteristics of local heterogeneity, entropy and intensity range, and one based on the number of objects after K-mean clustering. A classification model was obtained using a fivefold cross correlation algorithm. Sensitivity and specificity rates were 86% and 89.1%, respectively.

Widefield fluorescence imaging as an auxiliary tool to select the biopsy site for actinic cheilitis diagnosis

Actinic cheilitis (AC) is considered a potentially malignant disorder that mainly affects the lower lip, and it is caused by prolonged sun exposure. Clinical diagnosis relies on visual inspection by a trained clinician, when suspected of dysplasia changes, a biopsy is required. The heteregenous characteristics of the AC, makes the choice of the biopsy site a difficult task. Fluorescence detection has been presented as a useful tool to to detect biochemical and morphological tissue features related to cancer diagnosis, but still its effectiveness to discriminate premalignant lesion is not completely defined. In this clinical study, 57 AC patients were investigated using widefield fluorescence imaging (WFI) to evaluate the efficacy of this technique as an auxiliary tool to biopsy site location. A handheld fluorescence system based on 400-450 nm LED illumination Distinct trained clinicians evaluate the patient either with the conventional examination or the WFI, and were blinded to the other evaluation. A biopsy site was chosen based on the clinical examination, and another site was chosen using the fluorescence visualization. A total of 114 punch biopsies were performed, and 93% of the tissue samples presented epithelial dysplasia. The majority of the sites that presented moderate or severe dysplasia were sites chosen by WFI, showing its efficiency to improve the diagnosis of AC.