Use of parallel fluorescent confocal microscopy for detection of prostatic adenocarcinoma

OBJECTIVE: To provide a histological catalogue and defined criteria for the diagnosis of prostatic adenocarcinoma and its variants using the fluorescent confocal microscope (FCM) platform. METHODS: A total of 22 radical prostatectomy specimens were serially sectioned and scanned with the FCM. The prostatic tissue then underwent routine histological preparation. The FCM images were assessed against traditional haematoxylin and eosin images to document FCM prostatic histology. RESULTS: We first comprehensively catalogued FCM images of a wide range of benign and malignant prostate tissue. We then analysed and identified FCM features characteristic of cancer glands. They include fused or connected solid glands, lack of lumens, heterogeneous nuclear signals and lack of three-dimensional depth on greyscale imaging. Gleason patterns 3 and 4 cancer glands were morphologically different on FCM. The smallest focus of cancer detected on FCM was 0.7 × 1.2 mm Gleason score 3 + 3 = 6 cancer. CONCLUSION: The image atlas and the diagnostic criteria presented in this study will help train pathologists to proficiently use FCM for rapid intraoperative evaluation of surgical margins during radical prostatectomy.