Intraoperative Cytology Research Articles

Diagnostic Accuracy of Tumor Imprint Cytology for Ovarian Cancer

Background: Due to the lack of ovarian cancer screening tools, the combination of clinical findings, serum tumor markers, imaging, and tumor imprint cytology have been studied with the intention of treating the disease. Thus the aim is to determine the diagnostic accuracy of tumor cytology. Methods: Cross-sectional prospective study carried out on surgically treated ovarian tumors. The participants enrolled from the routine surgery list of the Gynecology Department from August 2022 to June 2024. An intraoperative tumor cytology test was done and compared with the final histopathology report. Descriptive statistics were used and diagnostic accuracy was calculated. Results: Out of 82 ovarian tumor surgeries one-third were histopathologically proven malignant tumors and the rest were benign conditions. The most common cancers were of epithelial origin followed by stromal and germ cell origin. The diagnostic accuracy of tumor cytology was 80.5% and two-thirds of cancers were correctly detected. Tumor markers could not consistently guide to characterize the tumor's nature. Conclusion: All malignant tumors had elevated tumor markers but were not exclusive. Tumor cytology together with imaging and tumor markers could help decide the extent of surgery.

The utilization of cytology for intraoperative diagnosis of primary central nervous system lymphoma

To investigate the diagnostic value of intraoperative cytology and rapid immunocytochemistry in primary central nervous system lymphoma. 254 cases of lymphoma and 82 cases of non-lymphoma were collected from 2010 to 2023. Frozen section(FS) was using alone in 44 cases during 2010–2014, FS and intraoperative cytology(IC) were using in 251 cases during 2015 to 2022. Rapid immunocytochemical(RICC, CD20, GFAP) were using with FS + IC in 41 cases during 2021 to 2023. Method One: According to the results of archives, statistic the diagnostic accuracy of lymphoma during three time periods. Method Two: All cases were randomly renumbered, 4 neuropathologists compared the accuracy of independent histology and that of combining cytology. The archives showed the diagnostic accuracy of FS in PCNSL was 77.27%, FS + IC was 86.06%, FS + IC + RICC was 92.68%. The retrospective study demonstrated the diagnostic accuracy of FS was 79.76%, FS + IC was 87.33% and FS + IC + RICC was 92.68%. The positive predictive value, negative predictive value, sensitivity, specificity and accuracy of CD20 were 100%, 76.92%, 90.32%, 100% and 92.68%, respectively. The results of the paired χ2 test was no statistically significant difference (0.05 < P < 0.1) between FS + IC + RICC and immunohistochemical (IHC) diagnosis of paraffin sections. The integration of IC + RICC + FS diagnosis can significantly enhance the intraoperative diagnostic accuracy of PCNSL and rectify potential errors that may occurred when relying solely on FS diagnosis.

Intraoperative peritoneal cytology for cervical gastric-type adenocarcinoma: Cytopathology and clinical impact.

The objective of this study was to elucidate the frequency and cytologic features of positive peritoneal washing cytology (PWC) in cervical gastric-type adenocarcinoma (GAS) and to clarify the clinical significance of positive PWC. The authors analyzed cases from their institution between 1991 and 2023 in which patients underwent surgery and PWC. The study included 62 patients who had cervical GAS (1991-2023; including seven patients with adenocarcinoma in situ and 26, 15, nine, and five patients with International Federation of Gynecology and Obstetrics 2018 stage I, II, III, and IV disease, respectively) and 100 patients who had usual-type endocervical adenocarcinoma (2007-2023; including 65, 15, and 20 patients with stage I, II, and III disease, respectively). The frequency of positive PWC results and cytologic features was assessed, and correlations between positive PWC results and clinicopathologic factors were examined, including prognosis, in the GAS group. Positive PWC results were significantly more frequent in patients who had GAS at 24% (15 of 62 patients) compared with 7% (seven of 100 patients) in those who had usual-type endocervical adenocarcinoma. The cytologic features of GAS included distinct cellular atypia (enlarged nuclei, nuclear irregularity) and frequent formation of spherical clusters (10 of 15 cases) without the golden-yellowish mucus commonly seen in cervical smears. A positive PWC result in GAS was significantly correlated with larger tumor size, parametrium invasion, lymph node metastasis, and elevated carbohydrate antigen 19-9 levels. In patients with stage I GAS, the PWC-positive group had significantly shorter disease-free survival and overall survival compared with the PWC-negative group. Positive PWC findings are frequent in cervical GAS and are associated with pathologic factors indicative of tumor growth and progression. In patients who have stage I GAS, positive PWC results may indicate a poor prognosis, warranting further investigation.

Lavage cytology diagnosed by immunostaining may be a poor prognostic factor in pathological stage III colorectal cancer

AbstractAimTo clarify the prognostic impact of positive lavage cytology diagnosed by immunostaining on long‐term outcomes following curative resection for pathological stage III colorectal cancer (CRC).MethodWe retrospectively investigated patients who underwent radical resection and intraoperative lavage cytology (LCY) simultaneously for pathological stage III primary CRC between 2005 and 2017. All LCY specimens were evaluated by Papanicolaou staining and immunostaining for carcinoembryonic antigen and Ber‐EP4. Only Class V diagnosed by either staining method was defined as positive LCY, and patients were classified into two groups: a positive lavage cytology (LCY+) group; and a negative lavage cytology (LCY−) group. Overall survival (OS) and relapse‐free survival (RFS) were compared between groups. Multivariate analysis was performed to identify clinicopathological factors affecting OS and RFS.ResultsAmong 708 patients with pathological stage III CRC, 30 patients (4.2%) showed positive LCY. OS and RFS were significantly lower in the LCY(+) group than in the LCY(−) group. Five‐y OS rates in the LCY(+) and LCY(−) groups were 58.7% and 91.0%, respectively, and 5‐y RFS rates were 28.8% and 76.6%, respectively. Multivariate analysis revealed that positive LCY was independently associated with lower OS and RFS. In the LCY(+) group, the proportion of patients with negative Papanicolaou staining but positive immunostaining was 20.0% (6 of 30). No significant differences in OS and RFS were evident between those patients and patients with positive results for both Papanicolaou staining and immunostaining.ConclusionPositive LCY as diagnosed by immunostaining may represent a poor prognostic factor for pathological stage III CRC.

Reliable intraoperative diagnostic methods for PCNSL: utility of combining intraoperative immunohistochemistry, cytology, and flow cytometry in achieving optimal treatment

Reliable intraoperative diagnostic methods for PCNSL: utility of combining intraoperative immunohistochemistry, cytology, and flow cytometry in achieving optimal treatment

Role of Intraoperative Bone Dust Cytology for Assessing Bone Margins: A Novel Technique

Role of Intraoperative Bone Dust Cytology for Assessing Bone Margins: A Novel Technique

Peritoneal lavage cytology in patients with curative resection for stage II and III colorectal cancer: A multi-institutional prospective study.

To clarify the usefulness of intraoperative lavage cytology in patients undergoing curative resection for pStage II-III colorectal cancer in a prospective multicenter study. Patients preoperatively diagnosed with stage II-III colorectal cancer between 2013 and 2017 from 20 hospitals were enrolled. Lavage cytology was performed twice during the surgery. The primary endpoint was the effect of lavage cytology on the 5-year relapse-free survival (RFS) in patients with pStage II-III colorectal cancer. The secondary endpoint was the effect of lavage cytology on the 5-year overall survival (OS) and peritoneal recurrence. A total of 1378 patients were eligible for analysis. The number of patients with pStage II-III colorectal cancer was 670 and 708, respectively. Fifty-four patients (3.9%) had positive cytological results. In pStage II patients, the 5-year RFS rates with positive and negative cytology were 61.1% and 81.6%, respectively (p = 0.023). The 5-year OS rates were 67.1% and 91.7%, respectively (p = 0.0083). However, there was no difference in RFS or OS between pStage III patients with positive and negative cytology results. The peritoneal recurrence rates were 11.8% and 1.5% in pStage II patients with positive and negative cytology results, respectively (p = 0.032). These rates were 10.5% and 2.5% in patients with stage III disease, respectively (p = 0.022). Stage II colorectal cancer patients with negative cytology had better outcomes than those with positive cytology. Peritoneal lavage cytology is useful for predicting peritoneal recurrence after curative resection of stage II-III colorectal cancer.

Comparison of Intraoperative Imprint Cytology versus Frozen Section for Sentinel Lymph Node Evaluation in Breast Cancer. A study along with Systematic Review and Meta-analysis of literature.

Sentinel lymph node (SLN) is the first lymph node to drain the lymph from a particular region involved by cancer. The commonly performed intraoperative methods for SLN evaluation are touch imprint cytology (TIC) and frozen section (FS). The present study aimed to determine the sensitivity, specificity and accuracy of TIC and FS with histopathological diagnosis as gold standard. The nodes were bissected along their long axis and wet surface was imprinted on to clean glass slides followed by toluidine blue and rapid Papanicolaou staining. Subsequently the lymph node slices were cut at three levels using the cryostat machine and stained with Hematoxylin and eosin stain. The cytological and FS findings were compared and the specificity, sensitivity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of TIC and FS was evaluated taking histopathological diagnosis as gold standard. In addition, pooled sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for touch imprint cytology and frozen section were assessed for the studies included in the meta-analysis. The specificity, sensitivity, diagnostic accuracy, positive predictive value and negative predictive value of touch imprint cytology were 100%, 88.2%, 90%, 100% and 60% respectively. The specificity, sensitivity, diagnostic accuracy, PPV and NPV of frozen section were 100%, 94.1%, 95%, 100% and 75% respectively. The sensitivity of TIC and FS for detection of micrometastasis was 60% and 80% respectively. The pooled sensitivity and specificity for touch imprint cytology were 85.24% (95% CI, 83.46%-86.90%), and 98.99% (95% CI, 98.69%-99.23%) respectively. The pooled sensitivity and specificity for frozen section examination were 90.45% (95% CI, 85.15%-94.34%), and 100% (95% CI, 99.24%-100%) respectively. Even though the sensitivity of FS was better than imprint cytology in detection of micrometastasis, TIC is a rapid inexpensive technique which can be utilized in remote areas in absence of cryostat machine. The sensitivity of the two techniques with respect to detection of macrometastasis was comparable. This meta-analysis highlights the accuracy of the touch imprint cytology and frozen section examination in the intra-operative detection of malignancy in breast cancer.

Label‐Free Virtual Peritoneal Lavage Cytology via Deep‐Learning‐Assisted Single‐Color Stimulated Raman Scattering Microscopy

Clinical guidelines for gastric cancer treatment recommend intraoperative peritoneal lavage cytology to detect free cancer cells. Patients with positive cytology require neoadjuvant chemotherapy instead of instant resection, and conversion to negative cytology results in improved survival. However, pathologists’ or artificial intelligence's accuracy of cytological diagnosis is disturbed by manually produced, unstandardized slides. In addition, the elaborate infrastructure makes cytology accessible to a limited number of medical institutes. This work develops CellGAN, a deep learning method that enables label‐free virtual peritoneal lavage cytology by producing virtual hematoxylin–eosin‐stained images with single‐color stimulated Raman scattering microscopy. A structural similarity loss is introduced to overcome the challenge of unsupervised virtual pathology techniques that cannot accurately present cellular structures. This method achieves a structural similarity of 0.820 ± 0.041 and a nucleus area consistency of 0.698 ± 0.102, indicating the staining fidelity outperforms the state‐of‐the‐art method. Diagnosis using virtually stained cells reaches 93.8% accuracy and substantial consistency with conventional staining. Single‐cell detection and classification on virtual slides achieve a mean average precision of 0.924 and an area under the receiver operating characteristic curve of 0.906, respectively. Collectively, this method achieves standardized and accurate virtual peritoneal lavage cytology and holds great potential for clinical translation.

Diagnostic utility of intraoperative squash smear cytology of Intra-cranial lesions in a resource limited setup of central India

IntroductionIntraoperative squash smear cytology is a useful diagnostic tool in case of CNS lesions. In resource poor countries where frozen section is unavailable, cytology is the mainstay method in giving a rapid intraoperative diagnosis which helps Surgeons regarding the extent of excision. The current study aims to assess the feasibility and accuracy of intraoperative squash cytology in evaluation of CNS tumors. Definitive diagnosis is confirmed by histopathological examination. Materials and methodsThis retrospective observational study was carried out at Department of Neuropathology. All patients diagnosed with space occupying lesion (SOL) in CNS were enrolled in the study. Intra-operative cytological diagnosis was compared to histopathological diagnosis. WHO classification of CNS tumors 2021 was used to classify tumors. ResultsTotal seventy patients with intracranial SOLs were enrolled in this study who were operated for the same and their specimens were examined. Two samples were found to be inadequate and not included in final analysis. Mean age was 38.8 ± 17.85 (SD). Male–female ratio was 1.5:1 with 41 (60.3%) males and 27 (39.7%) females. 58 had neoplastic and rest 10 had non-neoplastic lesions. Complete concordance was achieved in 61 cases (Diagnostic Accuracy-88.2%). 3 (4.4%) cases showed partial concordance and 4 (5.9%) were discordant. For detection of malignant lesions through squash smear cytology overall Sensitivity was 73.9%, Specificity-97.8%, Positive Predictive Value-94.4% and Negative Predictive Value-88%. ConclusionsSquash smear cytology is a simple, rapid and cost-effective method relying solely on the expertise of pathologist. High diagnostic accuracy can be achieved with squash cytology by taking clinical and radiological findings into consideration.

Efficacy of intraoperative imprint cytology of sentinel lymph node in breast cancer.

The most important determinant of patient outcome in cases of breast carcinoma is the regional lymph node status. Intraoperative assessment of sentinel lymph nodes (SLNs) allows the surgeon to perform axillary lymph node dissection in the same sitting if required. The commonly performed intraoperative methods for SLN evaluation are touch imprint cytology (TIC) and frozen section. The present study aimed to determine the sensitivity, specificity, and accuracy of TIC with histopathological diagnosis as gold standard. The lymph nodes sent for intraoperative examination were bisected along the long axis and touched onto clean glass slides followed by Toluidine blue and rapid Papanicolaou staining. The imprints were reviewed and the interpretation was conveyed to the surgeon. Thereafter, the biopsy was fixed in 10% formalin followed by paraffin embedding with hematoxylin and eosin staining. The specificity, sensitivity, diagnostic accuracy, positive predictive value, and negative predictive value were evaluated with histopathological diagnosis as gold standard. A total of 60 patients who underwent resection surgery were included in the study. Majority (36.7%) of patients were in the age group 41-50 years with a mean age of 48.1 ± 10.6 years. There were 54 cases (90%) and 6 cases (10%) of invasive carcinoma of no special type (ductal) and lobular carcinoma, respectively. According to modified Bloom-Richardson scoring, the cases were categorized as Grade 1-6 cases (10%), Grade 2-36 (60%), and Grade 3-18 (30%). The sensitivity and specificity of TIC were 87.5% and 100%, respectively. The diagnostic accuracy of TIC in the diagnosis of metastasis in SLN was 90%. TIC is an easy-to-perform, cost-effective, rapid, and accurate technique for axillary lymph node evaluation, which also overcomes the need for a cryostat.

Peritoneal lavage cytology in patients with curative resection for stage II and III colorectal cancer: A multi-institutional prospective study.

11 Background: Although various prognostic factors in patients with colorectal cancer has been reported, the usefulness of intraoperative lavage cytology in patients with colorectal cancer is controversial. The aim of this study was to clarify the usefulness of intraoperative lavage cytology in patients with curative resection for pSage II-III colorectal cancer in a prospective multicenter study. Methods: The 20 member hospitals of the Japanese Society for the Cancer of the Colon and Rectum prospectively registered the patients diagnosed as stage II or III colorectal cancer preoperatively between 2013 and 2017. Among these patients, pStage II-III patients went through analysis. Lavage cytology was performed twice during surgery. The first procedure was performed right after laparotomy, and the second was performed right after specimen retrieval. The primary endpoint of this study was an effect of lavage cytology on 5-year relapse-free survival (RFS) in patients with pStage II-III colorectal cancer. The secondary endpoint was an effect of lavage cytology on 5-year overall survival (OS) and peritoneal recurrence in patients with pStage II-III colorectal cancer. Results: A total of 1378 patients were eligible and went through analysis. The number of patients with pStage II and III colorectal cancer were 670 and 708, respectively. Among 1378 patients, 54 (3.9%) had positive cytology. The median follow-up period of the entire cohort was 5.3 years. In pStage II patients, the 5-year RFS rate with positive and negative cytology was 61.1% and 81.6%, respectively (P = 0.023). The 5-year OS rate of pStage II patients with positive and negative cytology was 67.1% and 91.7%, respectively (P = 0.0083). However, there was no difference in RFS and OS between patients with positive and negative cytology in pStage III patients. Thirty-three patients had peritoneal recurrence. The peritoneal recurrence rate was 11.8% and 1.5% in pStage II patients with positive and negative lavage cytology, respectively (P = 0.032). That was 10.5% and 2.5% in pStage III patients with positive and negative lavage cytology, respectively (P = 0.022). In total, 11.1% of patients with positive lavage cytology had peritoneal recurrence in this cohort. Conclusions: The pStage II colorectal cancer patients with negative cytology had better RFS and OS compared to those with positive cytology. Peritoneal lavage cytology was useful in predicting peritoneal recurrence after curative resection for pStage II-III colorectal cancer. Clinical trial information: UMIN000026070 .

Cytologic features of canine melanotroph and corticotroph pituitary adenomas.

The introduction of intraoperative cytology revolutionized neurosurgical procedures in human medicine, providing real-time diagnostic guidance to surgeons and contributing to improved patient outcomes. In the realm of veterinary medicine, the understanding of pituitary tumors in dogs and cats remains limited due to challenges in obtaining antemortem samples of central nervous system lesions. The aim of this study was to describe the cytologic features of pituitary adenomas in 12 dogs that underwent hypophysectomy. The series included nine melanotroph adenomas and three corticotroph adenomas. Definitive diagnosis was based on histopathology and immunohistochemistry. Cytologically, the adenomas had high numbers of bare nuclei and intact cells that were round to polygonal and situated individually or in small clusters. The intact cells had round to oval, eccentric nuclei with finely stippled chromatin and one to three prominent nucleoli and ample to abundant lightly basophilic to amphophilic, grainy cytoplasm with distinct borders, and variable numbers of discrete vacuoles. Mild-to-moderate anisocytosis and anisokaryosis, occasional binucleation, rare and atypical mitotic figures, and nuclear molding were also observed. The results suggest that intraoperative cytology of canine pituitary adenomas holds promise as a valuable diagnostic tool, aiding swift differentiation from other sellar masses before histologic confirmation. Cytologic characterization of pituitary adenomas in dogs is exceptionally rare in the scientific literature, making this study one of the first to offer a comprehensive description of these cytologic features.

Comparative study of intraoperative cytology, Frozen section and histopathology of ovarian neoplasms

Objective: To evaluate the role of intraoperative cytology in the diagnosis of ovarian tumours. Methods: A cross sectional study of 75 cases received from January 2016 to October 2021 was conducted in the Department of Pathology for ovarian neoplasms received for imprint cytology, frozen section and histopathology. On receiving the unfixed specimen per operatively, gross examination was performed and Imprint cytology/Scrape smears were obtained followed by staining of slides with field and rapid hematoxylin eosin stain. A few representative tissue sections were taken and processed for frozen section. After frozen section and imprint cytology reporting, specimens were fixed in formalin and processed for paraffin blocks for histopathological examination. Results of imprint cytology, frozen and paraffin sections were recorded and categorized as benign, borderline malignant. Accuracy of frozen section and imprint cytology was determined by comparing them with histopathology. Results: Of 75 lesions studied by intraoperative cytology,57 lesions were classified as benign and 18 as malignant. Comparing the diagnosis of cytology smears and frozen section with histopathology,72 of 75 cases were concordant. When imprint cytology and frozen section was compared with histology, sensitivity, specificity, positive predictive value and negative predictive value were 98.2%,89.4%,96.4% and 94.4% respectively. Conclusion: Imprint cytology is a boon for resource deprived settings and frozen section complements it in tertiary care centres for intraoperative diagnosis and determining the extent of surgical intervention required.

Correlation of intraoperative squash smear and histopathology in central nervous system lesions: A 6-year retrospective study in a tertiary care hospital in Kerala

Intraoperative squash smear cytology is considered to be of great value in intraoperative consultation of CNS pathology. It is a simple and reliable tool for rapid intraoperative diagnosis of CNS tumors. The study was undertaken to assess the accuracy of intraoperative squash smear in the diagnosis of CNS lesions and to correlate the squash cytology diagnosis with histopathological diagnosis taking the latter as the gold standard. A retrospective study of 38 cases of CNS lesions from which samples were collected by surgery or biopsy for intraoperative consultations and histopathological diagnosis. Radiologically confirmed cases were only included in the study. Smears were prepared from the biopsy sample obtained at the time of operation and were stained with hematoxylin and eosin. Remaining tissue submitted for histopathology was later correlated with intraoperative cytology diagnosis. Out of 38 cases, histopathological diagnosis was compatible with cytological diagnosis in 36 cases, two cases showed discrepancies. The diagnostic accuracy of squash cytology was 94.73%. Even though two cases were diagnosed differently in cytology, it was proved to be a malignant tumor both in squash cytology and histopathological diagnosis. Hence sensitivity, specificity, positive predictive value and negative predictive value in detecting the neoplastic condition on cytology was 100% respectively. Squash smear is a rapid, self-sufficient and cost effective method for the intraoperative diagnosis of CNS tumors. It can be considered as a mirror image to histopathological diagnosis and is of great value in intraoperative consultation of CNS pathology.

Case of Metastatic Atypical Meningioma to Lung: Utility of Cytological Preparations for Intraoperative Diagnosis

Abstract Introduction/Objective Meningiomas are the most common primary intracranial and intraspinal tumors. They are typically benign with an indolent behavior but can metastasize extracranially to the skin, bone, lymph node and liver. Lung metastasis is exceptionally rare, and the diagnosis can be challenging, especially during intraoperative diagnosis without ancillary studies. We describe a metastatic atypical meningioma to the lung for which intraoperative cytology facilitated the diagnosis and guided management. Methods/Case Report A 53-year-old woman with a history of left frontal atypical meningioma and multiple surgical resections for recurrences at outside hospitals, presented with an incidental left lung nodule. A lung wedge resection was performed and submitted for intraoperative diagnosis. Gross examination revealed a well-circumscribed, tan- white, and rubbery subpleural nodule. Cytological preparations— Diff-Quik and H&amp;E stains—and frozen section were prepared. Cytologically, the nodule displayed cohesive distinctive papillary whorls of uniform eosinophilic cells with indistinct cell membranes, round to oval nuclei with central nucleoli and intranuclear pseudoinclusions. The frozen section exhibited similar cytological features, few identifiable whorls and predominantly solid sheets of tumor cells typical of non-small cell carcinoma. Based primarily on the cytological findings, the intraoperative diagnosis was a neoplasm with papillary growth pattern, and a metastasis was favored based on the whorled pattern and clinical history; no further resection was performed. Permanent sections displayed mitoses and no necrosis. Immunohistochemical analysis revealed positivity for somatostatin receptor 2a, progesterone receptor, and EMA (focal); no staining was seen with pancytokeratin, TTF-1, or p40. A diagnosis of atypical meningioma, WHO grade 2, was rendered. Subsequently, an atypical cranial and temporalis muscle meningioma at the site of the prior craniotomy bone flap was resected and had an identical molecular profile (1p36 deletion) to that in the lung, further supporting metastasis to the lung. Results (if a Case Study enter NA) NA Conclusion This case illustrates a rare presentation of metastatic atypical meningioma and highlights the distinctive intraoperative utility of cytology preparations—architectural and cytological details—for diagnosis and appropriate management. Cytology preparations can be a valuable tool and complement frozen sections, in which certain morphological features may be less obvious or confounded by freezing artifact.

Cytopathology of glioneuronal and neuronal tumours with histological correlations.

Glioneuronal and neuronal tumours constitute a diverse group of tumours that feature neuronal differentiation. In mixed glioneuronal tumours, a glial component is present in addition to the neuronal component. With a few exceptions (eg diffuse leptomeningeal glioneuronal tumour) they are well-circumscribed and slow-growing tumours, which is why their prognosis is intrinsically favourable after gross total resection. Rendering an intraoperative diagnosis of glioneuronal/neuronal tumour is therefore important-neurosurgeons should remove them to prevent the persistence of clinical symptoms and/or recurrence. In this context, cytopathological examination can be especially useful for assessing cellular details when frozen section artefacts render poor-quality preparations, as is the case for this group of tumours, which are frequently mistaken for infiltrating gliomas (eg diffuse astrocytoma infiltrating grey matter, oligodendroglioma) on frozen section slides. The aim of this article is to review the cytomorphological features of glioneuronal and neuronal tumours according to the 2021 World Health Organization classification of central nervous system tumours, 5th edition. Additionally, since interpretation in intraoperative cytology relies on intuiting tissue patterns from cytology preparations, representative histological figures of all discussed entities have been included. Clues for specific diagnoses and the primary diagnostic problems encountered during intraoperative procedures are also discussed.

Cytological features of central nervous system germ cell tumours and tumours of the sellar region.

Germ cell tumours of the central nervous system and tumours of the sellar region represent a diverse group of neoplasms. These tumours affect both paediatric and adult patients and represent some of the most common central nervous system tumours as well as rare entities. Diagnosis frequently relies on tissue sampling, and intraoperative consultation is often needed to guide surgical management. The focus of this article is to provide a reference for the intraoperative cytology of these entities. The cytological features of these tumours as well as their differential diagnoses are described.

LC-1000 flow cytometry system complements intraoperative peritoneal cytology for pancreatic and biliary tract cancer.

The exfoliative cell analyzer, LC-1000, is medical device that utilizes the principles of flow cytometry, and might provide digital diagnostic information for cytology using a different approach from conventional cytomorphology. In this study, wae examined the usefulness of the LC-1000 as a diagnostic support system for intraoperative peritoneal lavage cytology and its prognostic impact for pancreatic (PC) and biliary tract cancer (BTC). Patients with PC and BTC who underwent surgical treatment were included. First, we identified useful indicators of LC-1000 and established cutoff values to discriminate positive cytology. Next, we verified the validity of these cutoff values. In the test set (n = 48), of the LC-1000 indicators examined, only MR-CPIx was significantly different between the negative and positive cytology groups, yielding a cutoff value of 0.86. In the validation set (n = 52), the sensitivity, specificity, positive and negative predictive value of the LC-1000 for cytology results was 1.0, 0.49, 0.11 and 1.0, respectively. In patients who had undergone radical resection, recurrence-free survival rate was significantly higher in the LC-1000 negative group than in the positive group in PC, but not in BTC. The LC-1000 was useful as digital support system for peritoneal cytology, and it might have potential as a prognostic factor for PC.

Intracranial squamous papillary lesion.

Intracranial lesions with squamous differentiation raise a diagnostic challenge, which can include benign or malignant, primary and metastatic lesions. Here is the case of a 49‐year‐old woman, in which intraoperative cytology helped the differential and final diagnosis.