To retrospectively investigate the diagnostic accuracy of FDG-PET/CT relative to CT for detection of cervical node metastases in patients with oral squamous cell carcinoma (OSCC), using histologic evaluation of dissected cervical nodes as the reference standard. Thirty-six patients with OSCC who underwent neck dissection (4 bilateral, 32 unilateral; 250 nodal levels) after FDG-PET/CT. Two observers consensually determined the lesion size and SUVmax of visible cervical nodes and compared the results with pathologic findings at the nodal level. Histopathology revealed nodal metastases in 13 (36.1 %) of 36 patients and 28 (11.2 %) of 250 nodal levels. Using a best discriminative SUVmax cut-off of 3.5 for the node, the sensitivity, specificity and accuracy of FDG-PET/CT for identification of nodal metastases on a level-by-level basis were 67.9, 94.6, and 91.6 %, respectively. The corresponding figures for CT were 42.9, 96.8, and 90.8 %, respectively. The sensitivity of FDG-PET/CT was significantly better than CT (p = 0.023). Moreover, using the level-based modified SUVmax cut-off, the respective figures for FDG-PET/CT were 71.4, 95.9, and 93.2 %, with significantly higher sensitivity (p = 0.013) and accuracy (p = 0.041) than CT. FDG PET/CT with SUVmax is a useful modality for preoperative evaluation of cervical neck lymph node metastases in patients with OSCC.

The current Food and Drug Administration-approved standard treatment for non-small cell carcinomas consists of carboplatin/taxol/avastin. However, nowadays more specialized protocols, depending on tumor subtype, are being used for lung cancer patients. Therefore, accurate differentiation between adenocarcinoma and squamous cell carcinoma is essential for the selection of appropriate therapies. We designed a rapid multiplex immunostaining method using a novel 4-antibody cocktail, YANA-4. This antibody cocktail consists of the following monoclonal antibodies: rabbit for thyroid transcription factor 1(TTF-1), mouse for napsin A, mouse l for p63, and rabbit for CK14. All procedures can be completed within 3 hours. This method labels the nuclei of adenocarcinomas as brown with TTF-1, and cytoplasm as blue with napsin A. Squamous cell carcinomas could be differentiated from adenocarcinomas with an inverse staining pattern: blue nuclei with p63 and brown cytoplasm with CK14. In this study, 97.4% (38 of 39) of adenocarcinomas showed brown nuclei (TTF-1) and/or blue cytoplasm (napsin A), with 4 cases showing positivity only for brown nuclei (TTF-1) and 1 case only for blue cytoplasm (napsin A). None of the squamous cell carcinoma cases showed these staining patterns. Positivity for blue nuclei (p63) and/or brown cytoplasm (CK14) was detected in 100% (25 of 25) of squamous cell carcinomas, with 1 case showing positivity only for brown cytoplasm (CK14) and 2 cases only for blue nuclei (p63). None of the adenocarcinoma cases showed these patterns. This rapid immunohistochemical method can thus be considered highly specific and sensitive for differentiating adenocarcinomas and squamous cell carcinomas.