Objective : To clarify the cell morphological differences among low-grade squamous intraepithelial lesion (LSIL)/cervical intraepithelial neoplasia (CIN) 1, high-grade squamous intraepithelial lesion (HSIL)/CIN2, and HSIL/CIN3.

Study Design : Among the patients who underwent cervical cytology between April 2013 and March 2016 and were diagnosed as having a LSIL or HSIL, we examined 42 patients with LSIL/CIN1, 37 with HSIL/CIN2, and 24 with HSIL/CIN3 in whom the diagnosis was confirmed by histological examination of biopsy material.

Results : The cytological findings of the specimens from patients with LSIL/CIN1, HSIL/CIN2 and HSIL/CIN3 are listed below. The appearance rates (numbers) of the parabasal type of atypical cells in LSIL/CIN1, HSIL/CIN2, and HSIL/CIN3 were 0.5% (9/1948), 2.9% (77/2671), and 49.7% (804/1619), respectively (p<0.01 for each). The optimal cutoff values of the number of parabasal type of atypical cells were LSIL/CIN1 vs. HSIL/CIN2 : 2.0, HSIL/CIN2 vs. HSIL/CIN3 : 9.0. The appearance rate of suspected squamous cell carcinoma cells, characteristically observed in patients with HSIL/CIN3, was 37.5% (p<0.01 for each).

Conclusion : In this study, we estimated the number of parabasal type of atypical cells and the appearance rate of suspected squamous cell carcinoma cells.

Objective : The aim of this study was to clarify the significance of discordance between the cytological diagnosis and histopathological diagnosis in biliary tract cytology specimens obtained using the Trefle^® device.

Study Design : We investigated the results of biliary cytology in specimens obtained using the Trefle^® device from cases of biliary tract stenosis between 2014 and 2019. Specimens were collected from a total of 252 cases, including 46 cases of benign bile duct stenosis and 206 cases of malignant bile duct stenosis. Cases of mismatch between the cytological diagnosis and histological diagnosis in samples obtained at the same time using the same device were reviewed.

Results : A total of 21 cases (8.3% of all cases), including 11 cytologically negative and histologically positive (C−H+) cases, and 10 cytologically positive and histologically negative (C+H−) cases were reviewed. Among the 11 C−H+cases, 8 were cases of well-differentiated adenocarcinoma, and 2 were cases of high-grade BilIN. In contrast, among the 10 C+H− cases, 6 were cases of pancreatic cancer with submucosal invasion of the biliary tract.

Conclusion : Mismatch between the cytological diagnosis and histological diagnosis may be observed in biliary tract cytology specimens obtained using the Trefle^® device. Attention must be paid to pseudonegative results of cytology in cases of well-differentiated adenocarcinoma of the biliary tract. In addition, in C+H− cases, one must take into account the possibility of pancreatic cancer with submucosal invasion of the biliary tract.

Objective : We examined the usefulness of rapid on-site cytological evaluation (ROSE) using Cyto Quick (CQ) staining in endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) cytology performed at Osaka Habikino Medical Center.

Study Design : We evaluated 89 patients who underwent ROSE of EBUS-TBNA samples at our Department of Pathology between April 2018 and July 2019. The concordance rate of the results of CQ staining with the results of Papanicolaou (Pap) staining and also with the results of histopathology of concurrently obtained tissue specimens was determined.

Results : The concordance rate between the results of CQ staining and Pap staining was 94.3%. In addition, in the 64 patients who were labeled as positive by CQ staining, the concordance rate with the results of histopathology of concurrently obtained tissue specimens was 89.1%.

Conclusion : CQ staining was easy to perform and could be performed within a short time, and the concordance rates with the results of Pap staining and histopathological examination were also good. CQ staining is a useful staining method for ROSE.

Objective : We attempted to improve the correct cytodiagnosis rate and interobserver variation by setting criteria for MALT lymphoma.

Study Design : Twenty-three cases of MALT lymphoma and 22 cases of chronic thyroiditis who had undergone both preoperative cytological and postoperative histological examinations were included. Useful findings for differentiating between the two were selected. They were strictly defined, and cutoff values were determined. Then, the findings of MALT lymphoma were assigned the score of +1, while those of chronic thyroiditis were scored as −1. Finally, the total score in each case was rated on a scale of −2 to +5.

Results : The five findings of mountain range-like clusters, lymphoglandular bodies, stringy crushed nuclei, irregular-shaped nuclei with prominent nucleoli, and nuclear diameter were significantly more frequent in MALT lymphoma, while follicular epithelial cell clusters and fibrous tissue fragments were significantly more frequent in chronic thyroiditis. The mean score was +2.7 in MALT lymphoma and −0.8 in chronic thyroiditis. Scores of ≥2, 1 and ≤0 were considered as corresponding to the cytological category of Positive, Undetermined significance and Negative, respectively. Based on these criteria, 39 out of the 45 cases were correctly diagnosed.

Conclusion : When diagnosing MALT lymphoma, it is important to focus on the 7 findings mentioned above. The scoring criteria improve the correct diagnosis rate and interobserver variations.

Background : Follicular carcinoma, oncocytic variant (FCOV) and follicular adenoma, oncocytic variant (FAOV), included in the histological diagnosis of thyroid tumors in Japan, are also called Hürthle cell carcinoma (oncocytic carcinoma) and Hürthle cell adenoma, respectively, according to the World Health Organization classification (2017). As FCOV and FAOV are classified based on the presence on histopathological examination of capsular invasion and/or vascular invasion, cytological differentiation was considered impossible ; however, recent studies have shown cytological differences between FCOV and FAOV. We attempted to review the cytological differences between FCOV and FAOV and to evaluate the fine-needle aspiration cytology findings of a thyroid tumor that was histopathologically diagnosed as FCOV 11 years after the initial cytology.

Case : A Japanese woman in her 40s was referred to our hospital for surgical treatment of a thyroid tumor. She had been under follow-up for a thyroid nodule for 10 years at a nearby hospital, and the nodule had recently increased in size from 2 cm to 6 cm. No metastases were observed. Surgery was performed and histopathology confirmed the diagnosis of FCOV. Fine-needle aspiration cytology of the thyroid tumor performed 11 years ago at our hospital had led to the suspicion of an oncocytic neoplasm, because oncocytic cells (discohesive, multiple nuclei, distinct nucleoli, large cell dysplasia, and transgressing blood vessels) were predominantly observed. Some of these cytological features are seen more frequently in FCOV than in FAOV, according to a literature review.

Conclusion : In the present case, FCOV could have been suspected ; however, decisions on the clinical management of FCOVs should not be based on cytological evaluation alone.

Background : A case of HPV-associated poorly differentiated adenocarcinoma of the cervix, stage ⅠA1, with neuroendocrine differentiation detected by cervical cytology during a comprehensive check-up system.

Case : The patient was a woman in her 50 s. Liquid-based cytology of the cervix revealed small round or oval tall columnar multinucleated tumor cells with a high N/C ratio, that were scattered singly. The tumor cells had coarse granular nuclear chromatin and prominent nucleoli, and some cells showed mitotic figures or rosette formation. The findings were considered as being consistent with poorly differentiated adenocarcinoma. Tissue specimens obtained by cervical conization showed an early lesion measuring 6 mm in transverse diameter, with a solid growth of tumor cells containing eosinophilic cytoplasm. Gland-like structures were found in some parts. The tumor cell nuclei had increased chromatin, prominent nucleoli, and mitotic or apoptotic figures. The basement membrane at the margin of the tumor nest was partly irregular, and the depth of stromal invasion was judged to be under 3 mm. Immunohistochemistry showed positive staining of the tumor cells for INSM-1, CD56 and p16, and the Ki-67 labeling index was ≥90%.

Conclusion : The cytological/histological findings were suggestive of poorly differentiated adenocarcinoma of the cervix, stage ⅠA1, with a highly malignant morphology, that required differentiation from large-cell neuroendocrine carcinoma.

Background : We predicted a PanNET with amyloid deposition by rapid on-site cytologic evaluation (ROSE) using the rapid CytoRich^TM (CR) method in EUS-FNA cytology of the pancreas.

Case : A woman in her 60 s was detected as having pancreatic duct dilatation by abdominal ultrasonography during a health checkup. As part of further detailed evaluation, pancreatic EUS-FNA with ROSE was performed. ROSE using the CR method revealed light green-stained amorphous material, small tumor cells with naked nuclei, and branching/tortuous vessels with spindle-shaped endothelial cells. Based on these findings, the patient was suspected as having a PanNET with amyloid deposition. Sections prepared from cell blocks revealed deposits that showed orange-red staining with Congo red and apple-green birefringence under polarized light microscopy, indicative of amyloid deposition. Immunohistochemistry showed positive staining of the tumor cells for INSM-1, chromogranin-A, synaptophysin, cluster of differentiation CD56, insulin, and Amyloid-A, and the Ki-67 index was ≤1%. From these findings, we confirmed the diagnosis of insulin-producing PanNET G1 with amyloid deposition.

Conclusion : In EUS-FNA cytology of pancreatic tumors, the cytological findings of amorphous material containing small tumor cells with naked nuclei and branching/tortuous vessels should raise the suspicion of PanNET with amyloid deposition.