Dietary feeding of Flavokawain A, a Kava chalcone, exhibits a satisfactory safety profile and its association with enhancement of phase II enzymes in mice.

Flavokawain A (FKA), a major chalcone in the Kava plant, has recently demonstrated promising anti-cancer activities. A systematic evaluation of FKA's safety profile has not been reported before. In this study, male FVB/N mice were fed with an AIN-76A diet or AIN-76A diet supplemented with 0.6% (6 g/kg food) FKA or 0.6% commercial kava root extract (KRE) for three weeks. Dietary feeding of FKA did not affect food consumption and body weight. Histopathological examination of liver, kidney, colon, lung, heart, spleen, and thymus revealed no signs of FKA-induced toxicity. Biochemical serum analysis and histological examination confirmed normal organ function in FKA-treated mice. The cytotoxicity profile showed FKA had minimal side effects on bone marrow and small intestinal epithelial cells compared with Adriamycin. In addition, oral feeding of FKA increased activities of both glutathione S-transferase and quinone reductase in the liver, lung, prostate and bladder tissues of mice. In comparison, dietary feeding of 0.6% KRE increased liver/body weight ratio and decreased spleen, thymus, and testis/body weight ratios, as well as induced nodular proliferation in liver tissues. Therefore, dietary feeding FKA showed no adverse effects on major organ function and homeostasis in mice, suggesting the potential of FKA for chemoprevention study of human cancers.

Cytopathologic, histopathologic, and immunohistochemical features of intrahepatic clear cell bile duct adenoma: a case report and review of the literature.

Intrahepatic clear cell bile duct adenoma is extremely rare, with only 3 previous cases reported in the literature. The cause of cytoplasmic clearing in clear cell bile duct adenoma has not been previously investigated. Distinguishing clear cell bile duct adenoma from other clear cell tumors, particularly clear cell cholangiocarcinoma, can be challenging. Previous studies have shown loss of CD10 expression and focal CD56 expression in cholangiocarcinoma. Expressions of CD10 and CD56 have not been previously studied in clear cell bile duct adenoma. A 37-year-old morbidly obese woman was diagnosed with a 2.8 cm intrahepatic clear cell bile duct adenoma following segmental hepatic resection. Histochemical analysis of the tumor suggested the cause of cytoplasmic clearing in the neoplastic cells to be mucin and not glycogen or lipid. On immunohistochemical staining, the neoplastic cells demonstrated staining for CK7, CA 19-9, polyclonal CEA, CD10 (apical), CD56 (focal), and vimentin. Ki-67 highlighted less than 2% of tumor cell nuclei. This is the first report to study the etiology of cell clearing in clear cell bile duct adenoma. Expression of CD10 in clear cell bile duct adenoma may help distinguish clear cell bile duct adenoma from clear cell cholangiocarcinoma.

Cytologic features of lipid-rich variant of pancreatic endocrine tumor-report of two cases with literature review.

Pancreatic endocrine tumor (PET) is an uncommon neoplasm of the pancreas with distinct cytomorphologic features. Lipid-rich PET, a rare variant, histologically deviates from that of a conventional PET. There is only one case report of the cytologic features of this rare entity in the literature. We report two cases of lipid-rich PETs diagnosed by endoscopic ultrasound-guided FNA biopsy. Case 1 showed large aggregates, small clusters, and single cells with plasmacytoid appearance, small uniform nuclei, coarse chromatin, and prominent nucleoli. Abundant distinct small cytoplasmic vacuoles were present in almost all tumor cells and the background was clean. Case 2 showed flat cohesive sheets of medium-sized uniform cells with indistinct plasmacytoid appearance, uniform nuclei, fine and evenly distributed chromatin, and inconspicuous nucleoli. Distinct small cytoplasmic vacuoles were seen only focally. Immunohistochemical stains in cell blocks of both cases confirmed the diagnosis of PET. Lipid-rich PET may be misinterpreted on cytology specimens if the pathologist is not aware of this rare entity since it mimics clear cell carcinoma of the kidney, adrenal cortical neoplasm, or adenocarcinoma of the pancreas.

Bowman birk inhibitor concentrate and oral leukoplakia: a randomized phase IIb trial.

Oral premalignancy serves as an ideal model for study of chemopreventive agents. Although 13-cis-retinoic acid showed reversal of oral premalignancy, toxicity, and reversal of clinical response after cessation of therapy obviated its widespread use. A search for nontoxic agents with cancer preventive activity led us to evaluate Bowman Birk Inhibitor (BBI) formulated as BBI Concentrate (BBIC). We previously reported encouraging results in a phase IIa trial of BBIC in patients with oral leukoplakia with measurable clinical responses and favorable biomarker changes. On the basis of these results, we undertook a randomized, placebo controlled phase IIb trial with patients receiving BBIC or placebo for 6 months, with assessment of clinical response and change in lesion area as primary end point and an intent-to-treat analysis. One hundred and thirty two subjects were randomized; and 89 subjects completed six months on study drug or placebo. Both placebo and BBIC showed a statistically significant decrease in mean lesion area of 17.1% and 20.6%, respectively, and partial or greater clinical responses of 30% and 28% respectively. No significant difference between placebo and study drug arms was observed. Histologic review, review of photographs of lesions, and comparison of serum neu protein and oral mucosal cell protease activity also did not show significant differences between study arms. Probable reasons for these negative results were considered, are discussed, and include a placebo with non-BBIC clinical activity and reduced pharmacokinetic availability of the second batch of BBIC. This experience should be a strong cautionary note to those considering "Green" chemoprevention.

High single-pass diagnostic yield of a new 25-gauge core biopsy needle for EUS-guided FNA biopsy in solid pancreatic lesions.

BACKGROUND: Current limitations of EUS-guided FNA include the need for multiple passes and on-site cytology assessment and lack of core specimen. Recently, a new 25-gauge core biopsy needle (PC25) was developed to overcome these limitations. OBJECTIVE: To determine the diagnostic yield of EUS-guided FNA aspiration biopsy (FNAB) when using the PC25 needle among patients with solid pancreatic lesions. DESIGN: Retrospective analysis. SETTING: Academic tertiary referral center. PATIENTS: Fifty consecutive patients with a solid pancreatic lesion underwent EUS-guided FNAB with PC25. INTERVENTIONS: EUS-guided FNAB with PC25. MAIN OUTCOME MEASUREMENTS: The primary outcome was the diagnostic yield in single and overall passes of EUS-guided FNAB when using the PC25 needle for pancreatic solid lesions. RESULTS: Cytologic analysis showed malignancy in 38 patients on the first pass, with a cumulative sensitivity of 83%, 91%, and 96% on passes 1, 2, and 3, respectively. Although visible core was reported in 46 patients (92%), histologic core was seen in 16 patients (32%). Histologic analysis showed malignancy in 29 patients on the first pass, with a cumulative sensitivity of 63% and 87% on pass 1 and passes 1 to 4, respectively. The sensitivity, specificity, and accuracy in combined cytologic and histologic results were 85%, 100%, and 86% for single pass and 96%, 100%, and 96% on multiple passes, respectively. No complications were seen. LIMITATIONS: A retrospective study design at a single center using a single arm. CONCLUSION: EUS-guided FNAB with the PC25 needle showed excellent single-pass and overall diagnostic yields. This needle appears to maintain a high cytologic yield, similar to standard 25-gauge FNA needles, while also providing some histologic core tissue.

Endoscopic ultrasound-guided paracentesis of ascitic fluid: a morphologic study with ultrasonographic correlation.

BACKGROUND: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been widely used for the diagnosis of primary and metastatic gastrointestinal (GI) and non-GI malignancies. Few studies have been published to evaluate the accuracy and the cytologic features of EUS-guided paracentesis in the diagnosis and staging of malignant neoplasms. METHODS: All EUS-guided paracenteses of ascitic fluid performed at the University of California Irvine Medical Center (UCIMC) from January 2003 to February 2006 were retrospectively retrieved. Corresponding EUS findings, cytology and histology slides, and follow-up information were reviewed. RESULTS: One hundred one (101) cases were found. Two smears were submitted in 11 cases because of the scanty amount of fluid aspirated. In the remaining cases, 5 mL or less of fluid were aspirated in 56 patients, and, of 9 who had prior computed tomography (CT), ascitic fluid was not seen in 6. The cytologic diagnoses were as follows: 17 were positive for adenocarcinoma, 1 positive for metastatic small-cell carcinoma of the lung, 1 positive for diffuse large-cell lymphoma, 3 suspicious for adenocarcinoma, 1 suspicious for plasmacytoma, 4 atypical epithelial cells, and 74 negative. Cell block was available in 80 cases and immunohistochemical stains were performed in 71 cases to confirm the diagnosis. Six patients had peritoneal biopsy. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were 80%, 100%, 100%, 95%, and 96%, respectively. CONCLUSIONS: EUS-guided paracentesis is a valuable aid in the cytologic diagnosis of malignant ascites. It is particularly useful when no abnormality is identified by CT.

An immunohistochemical and fluorescence in situ hybridization-based comparison between the Oracle HER2 Bond Immunohistochemical System, Dako HercepTest, and Vysis PathVysion HER2 FISH using both commercially validated and modified ASCO/CAP and United Kingdom HER2 IHC scoring guidelines.

Immunohistochemistry (IHC) is used as the frontline assay to determine HER2 status in invasive breast cancer patients. The aim of the study was to compare the performance of the Leica Oracle HER2 Bond IHC System (Oracle) with the current most readily accepted Dako HercepTest (HercepTest), using both commercially validated and modified ASCO/CAP and UK HER2 IHC scoring guidelines. A total of 445 breast cancer samples from 3 international clinical HER2 referral centers were stained with the 2 test systems and scored in a blinded fashion by experienced pathologists. The overall agreement between the 2 tests in a 3×3 (negative, equivocal and positive) analysis shows a concordance of 86.7% and 86.3%, respectively when analyzed using commercially validated and modified ASCO/CAP and UK HER2 IHC scoring guidelines. There is a good concordance between the Oracle and the HercepTest. The advantages of a complete fully automated test such as the Oracle include standardization of key analytical factors and improved turn around time. The implementation of the modified ASCO/CAP and UK HER2 IHC scoring guidelines has minimal effect on either assay interpretation, showing that Oracle can be used as a methodology for accurately determining HER2 IHC status in formalin fixed, paraffin-embedded breast cancer tissue.

Cytologic diagnosis of chordoma in a peritoneal effusion: a case report.

BACKGROUND: Chordoma, a distinct malignant neoplasm arising from the remnants of the notochord, occurs mostly in patients in the fifth to seventh decade of life. Metastasis occurs in 20-30% of cases. The most common metastatic sites are lungs and, less commonly, other bones and visceral organs. The cytologic features of chordoma in both primary and metastatic foci have been described for specimens obtained by fine needle aspiration biopsy. A few cases have been reported in the sputum and the cerebrospinal fluid. CASE: A 57-year-old man presented with metastatic chordoma diagnosed in a peritoneal effusion. Cytospin slides of the effusion showed numerous individual and clusters of polygonal, round epithelial cells with a background of myxoid chondroid substance, which stained metachromatic on Diff-Quik slides. Many diagnostic physaliphorous cells were present and characterized by abundant intracytoplasmic vacuoles of various sizes. The nuclei were monotonous, with minimal anisonucleosis. The nuclei had evenly dispersed chromatin with occasional small, eosinophilic nucleoli. The nuclear membranes were smooth, with focal indentation. The differential diagnosis included an adenocarcinoma and metastatic chordoma. Immunohistochemistry applied to the cell block showed that the neoplastic cells were positive for cytokeratin and S-100 protein. CONCLUSION: The clinical history with immunohistochemical profiles helped confirm the diagnosis of metastatic chordoma.

Follicular neoplasm of the thyroid gland: unique cytologic appearances in a fine-needle aspiration biopsy.

Fine-needle aspiration (FNA) biopsy has become a standard first-line diagnostic procedure for palpable and nonpalpable nodules of the thyroid gland. Six cytologic diagnostic categories have recently been proposed to unify the terminology that is linked to proper clinical management. We report a case of follicular neoplasm diagnosed on FNA specimen that had a very artistic appearance of the microfollicle formation on both Diff-Quik and Papanicolaou-stained slides.

Atypical lipomatous tumor/well-differentiated liposarcoma of the parotid gland: case report and literature review.

Although liposarcoma is the second most common soft-tissue sarcoma in adults, it is exceedingly rare in the head and neck. According to our MEDLINE search, only 11 cases of liposarcoma of the parotid gland have been reported since 1968. We report a new case of primary atypical lipomatous tumor/well-differentiated liposarcoma of the parotid gland in a 77-year-old man. Because only a very limited number of case reports and small series have been published on liposarcoma in the head and neck, we also provide a review of the literature on this uncommon disease entity.

Radical surgical cytoreduction of progressive leiomyomatosis peritonealis disseminata: a case report.

BACKGROUND: Leiomyomatosis peritonealis disseminata (LPD) is an uncommon, benign smooth muscle condition of the peritoneal cavity that appears clinically as a metastatic malignant neoplasm. Generally, radical surgery is not recommended. This unique case involves curative radical surgery after disease progression during depo-medroxyprogesterone acetate therapy. In vitro assays and future implications are discussed. CASE: A 31-year-old woman presented with abdominal pain and uterine leiomyomas. During exploratory laparotomy, she had gross evidence of LPD. Despite initial surgery and hormonal therapy, she had progression of disease. She then underwent optimal cytoreductive surgery. Tumor response to megestrol acetate in vitro was evaluated and noted to be heterogeneous; therefore it was not given as adjuvant therapy. Five years after radical surgery, she was without evidence of disease, CONCLUSION: Radical secondary cytoreductive surgery can achieve a durable remission for LPD refractory to primary surgical castration and depomedroxyprogesterone acetate therapy.

Cytologic diagnosis of hemophagocytic lymphohistiocytosis in ascitic fluid: a case report.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH), also known as macrophage activation syndrome, is a rare, fatal hematopoietic disease. Its cytologic features may be subtle because the abnormal histiocytes may not be recognized if one is not aware of this entity. We report a case of HLH involving the ascitic fluid. CASE REPORT: A 73-year-old man developed weakness, lethargy, decreased appetite and progressive shortness of breath after a cholecystectomy. Physical examination revealed hypotension, tachycardia and chest dullness with decreased breath sounds bilaterally. Radiologic examination revealed bilateral pleural effusions. The patient accumulated fluid in the peritoneal cavity, lungs, retroperitoneum and mediastinum. Bone marrow biopsy showed abundant histiocytes infiltrating the marrow cavity, and many of these histiocytes contained cellular debris. A diagnosis of HLH was therefore made. The abdominal paracentesis specimen contained many similar histiocytes exhibiting erythrophagocytosis and lymphophagocytosis. These abnormal histiocytes were positive for CD68 and negative for AE1/AE3, confirming the diagnosis of HLH. The patient died soon after from disseminated aspergillosis. CONCLUSION: HLH is cytologically characterized by the presence of abnormal histiocytes with ingested cellular debris. In serous effusions they should not be confused with mesothelial cells. Immunohistochemical studies may help confirm the diagnosis.

Cytologic diagnosis of mastocytosis by fine needle aspiration biopsy: a case report.

BACKGROUND: Mastocytosis is an abnormal proliferation of mast cells and their subsequent accumulation in various organs. Diagnosis of mast cell disease relies on proper identification of abnormal mast cells. CASE: A 55-year-old man presented with a history of fever for several months, associated with night sweats, involuntary 20lb weight loss, progressive fatigue, weakness, worsening abdominal distention, shortness of breath, and diffuse lymphadenopathy. Physical examination and computed tomography (CT) showed hepatosplenomegaly, massive ascites, and generalized lymphadenopathy. Bone marrow biopsy with immunohistochemistry (ICH) studies revealed mastocytosis. CT-guided fine needle aspiration biopsy (FNAB) of the retroperitoneal lymphadenopathy was performed. The smears were cellular for a mixed population of mature plasma cells, eosinophils, left-shifted granular and lymphoid cells, and abundant abnormal mast cells. The mast cells had round to oval lobulated nuclei, some of which were binucleated or eccentrically located, with coarse, evenly distributed chromatin. Abundant pale cytoplasm contained numerous metachromatic granules. IHC studies and flow cytometry confirmed the cytologic diagnosis of mastocytosis. CONCLUSION: This case highlights the cytologic features of mastocytosis in FNA specimens. IHC stains and flow cytometry are helpful to confirm the cytologic diagnosis. To the best of our knowledge, this is the second case that describes the cytologic characteristics of mastocytosis.

Burkitt's lymphoma of the base of the tongue: a case report and review of the literature.

Burkitt's lymphoma is a highly aggressive, mature B cell non-Hodgkin's lymphoma that is rare outside Africa. We report a case of Burkitt's lymphoma presenting as a rapidly expanding tongue-base mass that caused airway obstruction in an 80-year-old Palestinian man living in California. According to our review of the literature, this is only the third reported case of Burkitt's lymphoma arising in the base of the tongue. We also discuss the incidence, epidemiology, genetics, prognosis, and treatment of this malignancy. Because Burkitt's lymphoma is one of the fastest-growing tumors in humans, rapid diagnosis and treatment are important. Treatment involves brief-duration, high-intensity chemotherapy and central nervous system prophylaxis. It is important for the otolaryngologist to recognize this disease and to understand the steps necessary to treat this aggressive tumor.

Endoscopic ultrasound-guided fine-needle aspiration of undifferentiated carcinoma with osteoclast-like giant cells of the pancreas: a report of 2 cases with literature review.

Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas is rare. Histologically it mimics the giant cell tumor of the bone and may be associated with a ductal adenocarcinoma. We recently encountered two such cases, both of which were biopsied by EUS-guided FNA. Abundant multinucleated osteoclast-like giant cells and many uniform mononuclear cells were present in case 1 so that the diagnosis was made. In case 2, many mononuclear tumor cells with vacuolated and basophilic cytoplasm were present, and rare osteoclast-like giant cells were seen. A diagnosis of adenocarcinoma was made. In both cases, no conspicuous nuclear pleomorphism was noted in the mononuclear cells or the multinucleated giant cells. The histology of case 2 revealed a pure undifferentiated carcinoma with osteoclast-like giant cells. In addition, a liver biopsy revealed globular amyloidosis. To our knowledge, this is the first report of pancreatic undifferentiated carcinoma with osteoclast-like giant cells sampled by EUS-guided FNA and the first case of hepatic globular amyloidosis associated with this tumor.

Margin distance and other clinico-pathologic prognostic factors in vulvar carcinoma: a multivariate analysis.

OBJECTIVES: To determine the importance of margin status and other prognostic factors associated with the recurrence and survival of patients with squamous cell vulvar carcinoma. METHODS: Data were analyzed using Kaplan-Meier methods and Cox proportional hazards regression. All slides were re-reviewed by two gynecologic pathologists. RESULTS: Ninety patients (median age: 69) were treated for vulvar carcinoma from 1984 to 2002, including 28 FIGO stage I, 20 stage II, 26 stage III and 16 with stage IV disease. Sixty-three (70%) patients underwent complete radical vulvectomies and 27 (30%) had modified radical vulvectomies. Nineteen (20%) patients received adjuvant radiotherapy. Five-year disease-specific survival rates were 100%, 100%, 86% and 29% for stages I-IV, respectively. None of the 30 patients with a pathologic margin distance >8 mm had local recurrence. Of the 53 women with tumor-free pathologic margin of <8 mm, 12 (23%) had a local recurrence. Moreover, women with >2 positive groin nodes had significantly higher recurrence risk compared to those with <2 metastatic groin nodes (p<0.001). On multivariate analysis, positive groin nodes and margin distance were important prognostic factors for recurrence. Moreover, stage, tumor size, margin distance, and depth of invasion were significant independent predictors for disease-specific survival. The median follow-up was 58 months (range: 2-188). CONCLUSIONS: Pathologic margin distance is an important predictor of local vulvar recurrence. Our data suggest that a > or =8-mm pathologic margin clearance leads to a high rate of loco-regional control.

In vivo optical coherence tomography of the human oral cavity and oropharynx.

Optical coherence tomography (OCT) is an evolving imaging modality that combines interferometry with low-coherence light to produce high-resolution tissue imaging. Cross-sectional in vivo images were obtained using an OCT device consisting of a Michelson interferometer, 1.3-microm broadband light source, and a handheld fiberoptic imaging probe. Image pixel resolution approached 10 microm. The mucosa of the oral cavity and oropharynx were examined in 41 patients during operative endoscopy. Optical coherence tomographic imaging was combined with endoscopic photography for gross and histologic image correlation. Optical coherence tomographic images of the oral cavity and oropharynx provided microanatomical information on the epithelium, basement membrane (BM), and supporting lamina propria (LP) of the mucosa. Normal microstructures identified in these tissues included an overlying keratin layer, papillae, ducts, glands, and blood vessels. Regions of pathologic features studied included mature scar, granulation tissue, mucous cysts, leukoplakia, and invasive cancer. Optical coherence tomographic imaging showed distinct zones of normal, altered, and ablated tissue microstructures for each pathologic process studied. Abnormal findings were directly compared with regions of normal tissue or conventional histopathologic features when tissue for analysis was available. This study provides a composite series of in vivo OCT images of the oral cavity and oropharynx in a variety of normal regions and pathologic states as well as outline future applications of OCT technology.

Eccrine porocarcinoma: Report of a case with fine needle aspiration cytology, histopathology and immunohistochemistry.

BACKGROUND: Although relatively rare, eccrine porocarcinoma (EP) is widely recognized in the literature as the most common of the sweat gland adenocarcinoma types. EP is an adenocarcinoma of the eccrine sweat gland with a propensity to recur locally and metastasize to regional lymph nodes. This paper presents the second case of fine needle aspiration (FNA) cytology of an EP along with histopathology and immunohistochemistry. CASE: A 64-year-old Filipino woman had a history of EP of the right eyebrow and presented with a right preauricular mass. The cytopathologic features of the case included: (1) clusters and sheets of polyhedral epithelial tumor cells with abundant, cyanophilic, vacuolated cytoplasm; round to oval, hyperchromatic nuclei; and occasional prominent nucleoli; (2) multinucleated tumor cells; (3) singly dispersed and relatively large aggregates of parakeratotic squamous cells; and (4) a background of necrotic debris. CONCLUSION: EP is crucial to developing an effective (curative) surgical plan. FNA cytology potentially provides a convenient, safe and effective approach to solving a challenging differential diagnosis. The constellation of cytologic findings probably is distinctive and, in the proper clinical setting, may be diagnostic. History is important in making an accurate diagnosis.

Optical coherence tomography of laryngeal cancer.

OBJECTIVES: Optical coherence tomography (OCT) is a high-resolution optical imaging technique that produces cross-sectional images of living tissues using light in a manner similar to ultrasound. This prospective study evaluated the ability of OCT to identify the characteristics of laryngeal cancer and measure changes in the basement membrane, tissue microstructure, and the transition zone at the edge of tumors. MATERIALS AND METHODS: One hundred thirty-three patients underwent OCT examination during surgical endoscopy of the head and neck. Twenty-two patients with laryngeal cancer or a history of laryngeal cancer were imaged with a fiberoptic OCT system. Tumor and adjacent transition zones were imaged along with uninvolved subsites. OCT images were correlated with histopathology. RESULTS: Twenty-six OCT examinations were performed in 22 patients. Basement membrane disruption was seen in 18 subjects, all of whom had histology showing classic features of cancer. A transition zone to uninvolved epithelium at the tumor periphery was also often observed. In six studies, benign or premalignant processes were histologically confirmed. In three thin, superficial lesions, an intact basement membrane was observed. The basement membrane could not be identified in three other bulky exophytic, premalignant lesions, primarily because of increased superficial signal backscattering observed in pathologic tissues. CONCLUSIONS: OCT clearly identifies basement membrane violation from laryngeal cancer and can identify transition zones at the cancer margin. In bulky exophytic lesions, OCT signal may not penetrate deeply enough to show the basement membrane, but for many suspicious lesions that require exclusion of cancer, OCT shows potential for assisting in diagnostic assessment.

In vivo optical coherence tomography of the human larynx: normative and benign pathology in 82 patients.

OBJECTIVES: Optical coherence tomography (OCT) is an emerging imaging modality that combines low-coherence light with interferometry to produce cross-sectional images of tissue with resolution about 10 mum. Patients undergoing surgical head and neck endoscopy were examined using a fiberoptic OCT imaging probe to study and characterize microstructural anatomy and features of the larynx and benign laryngeal pathology in vivo. STUDY DESIGN: Prospective clinical trial. MATERIALS AND METHODS: OCT imaging of the larynx was performed in 82 of 115 patients who underwent surgical endoscopy for various head and neck pathologies. The OCT device employs a 1.3 microm broadband light source (FWHM, 80 nm). The frame rate is 1 Hz. Imaging was performed using a handheld probe placed in near contact with the target site. The maximum axial and lateral dimensions for the region of interest imaged were 2.5 mm x 6 mm, with resolutions of 10 microm. Simultaneously, conventional endoscopic images were obtained to provide anatomic correlation with OCT images and histology. Optical micrometry was performed to measure the epithelium thickness. RESULTS: Systematic OCT imaging of laryngeal structures and subsites provided information on the thickness of the epithelium, integrity of the basement membrane, and structure of the lamina propria. Microstructural features identified included glands, ducts, blood vessels, fluid collection/edema, and the transitions between pseudostratified columnar and stratified squamous epithelium. The mean epithelial thickness of laryngeal subsites was calculated: true vocal cord (129 microm), false vocal cords (124 microm), aryepiglottic fold (177 microm), subglottis (98 microm), and epiglottis (185 microm). True vocal cord pathology imaged included Reinke's edema, papillomatosis, polyps, mucous cysts, and granulation tissue. Subglottic imaging identified boundaries between epithelium, lamina propria, and cartilage. The OCT images compared favorably with conventional histopathology. CONCLUSION: OCT has the unique ability to image laryngeal tissue microstructure and can detail microanatomic changes in benign, premalignant, and malignant laryngeal pathologies. OCT holds the potential to guide surgical biopsies, direct therapy, and monitor disease, particularly when office-based systems are developed. This is a promising imaging modality to study the larynx.