Context .- Urothelial carcinoma in situ (CIS) is a precursor of invasive bladder cancer, which if left untreated, will likely progress to more aggressive disease. Approximately 50% of CIS lesions are missed on routine cystoscopy owing to their flat architecture. Furthermore, many benign but abnormal-appearing areas may be biopsied owing to lack of cellular resolution of cystoscopes. Multiphoton microscopy (MPM) is an optical imaging technique that generates subcellular-resolution three-dimensional images from unfixed tissue without using exogenous dyes. Objective .- To assess the diagnostic potential of MPM in identifying and differentiating benign from malignant flat bladder lesions, especially CIS. Design .- Seventy-eight specimens (benign = 46, CIS = 23, invasive = 9, as diagnosed on histopathology) were obtained from flat bladder mucosa via transurethral resection of bladder, cold cup biopsy, or cystectomy, imaged fresh with a commercial benchtop MPM, and submitted for routine histopathology. Multiphoton microscopy and hematoxylin-eosin diagnoses were compared. Results .- In 77 of 78 specimens (99%), accurate MPM diagnoses (benign/malignant) were given on the basis of their architectural and cytologic features (nuclear to cytoplasmic ratio, pleomorphism, polarity/organization of urothelial layers, etc). The sensitivity and specificity were 97% and 100%, respectively, with positive (malignant) and negative (benign) predictive values of 100% and 98%, respectively. The interobserver agreement, κ, was 0.93. Conclusions .- Our study demonstrates the capability of MPM to identify and differentiate benign from malignant flat bladder lesions, especially CIS. With the advent of MPM endoscopes, we foresee their potential as a biopsy guidance tool for early detection and treatment of CIS, thus reducing the rate of biopsies with benign diagnoses and their associated complications.
背景 尿路上皮原位癌（CIS）是浸润性膀胱癌的前驱病变，如果不及时治疗，可能会发展为更具侵袭性的疾病。由于病变多呈扁平状，因此常规膀胱镜检查有大约50% CIS漏诊。此外，许多良性但表现异常的区域可能由于膀胱镜分辨不足而进行了活检。多光子显微镜（MPM）是一种光学成像技术，可以对未固定组织不使用外源性染料形成亚细胞分辨率的三维图像。
结果 MPM依据组织结构和细胞学特征（核浆比、细胞多形性、极性/泌尿上皮层次，等） 77/78例（99%）诊断（良性/恶性）准确。敏感性和特异性分别为97%和100%，阳性（恶性）和阴性（良性）的预测值分别为100%和98%。观察者之间具有一致性，κ值为0.93。