Evaluating intraoperative cytology with histopathology diagnosis and its importance in ovarian tumors

Results: Both touch / imprint cytology were able to diagnose benign and malignant ovarian neoplasm. Out of 103 cases, in cytology showed 89.1% patients were negative and 10.9% patients were positive. Histopathology shows 84.2% of benign ovarian neoplasm, 3.9% borderline neoplasm and 11.9% of malignant. Diagnostic accuracy of touch/ imprint was 99% with sensitivity 100% and specificity was 91.67%. Positive predictive value was 98.89% and negative predictive value was 100%.


INTRODUCTION
Dudgeon and Patrick from London developed a simple method to obtain rapid diagnosis of freshly cut specimens, in 1927. 1 Popularity of touch imprint has increased in cytopathology practice after increase of hematopathology case and frozen section. Intraoperative cytology (IC) is performed by taking imprint smears from the cancerous tissue and establishing an early diagnosis at the operation site. 2 Ovarian cancer is eight most common cancer among women, and it includes about 4% of all women's cancer. 3 Lifetime risk of ovarian cancer in women is one in 71, and the chance of dying from the disease is 1 in 95. 4 Malignant epithelial tumors of ovary are usually aggressive and they 1634 DOI : 10 need extensive surgery that at times requires bilateral saplingo-oophorectomy and total abdominal hysterectomy; mostly followed by chemotherapy. Patients with benign epithelial tumors may present with features mimicking malignancy like large abdominal-pelvic mass in case of mucinous cystadenoma, however if correctly diagnosed on IC, requires cystectomy only. 5 Intraoperative cytology diagnosis helps to manage patient during the operative procedure and process further in the benefit of the patient management. Preliminary diagnosis helps to provide the specific therapy in time, reducing morbidity and mortality. Histopathology is the gold standard and definitive pathology diagnosis, whereas touch imprints are used for detecting preliminary diagnosis for malignant and benign condition. Touch imprint cytology has got definite role in Intra operative diagnosis that would guide the Surgeon's hand. 6 Imprint is a touch preparation in which tissue is touched on the slide and leaves behind its imprint in the form of cells on the glass slide. 7 The literature suggests that intraoperative touch imprint cytology can be useful in evaluation of margin. 8 Thus, in an intraoperative consultation, the application of both imprint cytology and histological diagnosis of frozen sections has been recommended for ovarian tumors. [9][10][11] We underwent this study to evaluate the accuracy of imprint cytology/ touch preparation in the diagnosis of ovarian neoplasms and correlate it with histopathological diagnosis.

MATERIALS AND METHODS
We conducted a prospective study of total 103 resected ovarian neoplasm in our Pathology department of Paropakar Maternity and Women's Hospital over a period of 10 months (2018 June 1st-2019 to March 31). The entire sample operated in Gynecology surgery with solid and cystic ovarian mass was included. Insufficient cellularity in touch imprint and emergency operation for ovarian mass were excluded from the study. The lesions were cut when fresh and tissue was obtained from representative area from solid and cystic component. Samples for cytology were obtained from several parts of tumors presenting different gross morphology. Tissue was firmly touched or representative samples were cut and firmly pressed on the clean dry leveled frosted glass slides and wet smear were immediately fixed in 95% ethanol or 80% isopropyl alcohol. Air dried smear were stained with rapid Giemsa stain. Wet smear were processed for rapid Papanicolaou method. The slides were immediately dipped in hematoxylin for 1 min, rinsed rapidly with distilled water, differentiated with ammonium hydroxide, counterstained with eosin by three slow dips, washed in tap water, dried, mounted on glass slides and covered with a coverslip. The time consumed for taking imprints, staining and reporting was 20 minutes. 12 The smears were evaluated for cellularity, arrangement of epithelial cells, cellular features of malignancy, necrosis and background. All benign and borderline lesions were reported as negative for malignancy. And malignant lesions were reported as positive for malignancy. Histopathology diagnosis was considered as the gold standard for statistical evaluation. All surgical resection specimens were fixed in 10% formalin were routinely processed. Histopathology diagnosis of paraffin embedded tissue sections was made by H.E staining and compared with the results of Imprint Cytology. The histopathology diagnosis of ovarian tumor was made according to WHO classification. 13 The results were statistically evaluated for sensitivity, specificity, positive predictive value and overall accuracy of diagnosis. The statistical analysis of data was performed by Microsoft Excel 2013.

RESULTS
All together the study included 103 patients with ovarian mass diagnosed by clinical examination, ultrasonography and CT scan examination. Imprint cytology smears were performed in all patients. Out of which two were excluded from the study due to in sufficient material. The age ranged from 12 years to 68 years with mean age of 34 year. The malignant ovarian tumor was among patient with age of 12 year to 57 years with mean age of 35.7 years (Table. 1   benign imprint cytology report turns out to be malignant in histopathology diagnosis, thus giving one false negative case in our study. Correlation between imprint cytology with that of histopathology diagnosis was shown in Table  2. We found a satisfactory diagnostic accuracy of the intraoperative imprint cytology (99%) in our study. The imprint cytology does not match with 1% cases with the histological diagnosis.
Based on above findings sensitivity of imprint cytology in our study was 91.67% and specificity was 100.0%. Positive predictive value was 100.0% and Negative predictive value was 98.89%.
Positivity of tumor markers was seen in benign, borderline, and malignant ovarian neoplasm are shown in figure 3.
Among the malignant ovarian tumors, tumor markers were not performed in one case of serous carcinoma. CA125 was increased in four cases of serous carcinoma and in two cases LDH was increased. One case each of mucinous carcinoma showed increased levels of CA125, LDH, CEA and AFP. AFP was also raised in one case of clear cell carcinoma and one of immature teratoma, however, the level of AFP was markedly elevated (more than 1000) in the case of Yolk sac tumor only. The case of immature teratoma also showed increase in LDH.

DISCUSSION
Intraoperative imprint cytology is one of the important diagnostic tools for any suspicious of doubtful ovarian neoplasm, which can help surgeon how to proceed for further surgery. In the places where there is limitation to acces other means of diagnosis tools it play very important role. Michael C et al. and Khalid A et al. also mentioned in their articles that imprint cytology is probably the only means of rapid intraoperative consultation where acces to intraoperative histological diagnosis is limited. 14,15 This study is to describe intraoperative accuracy of imprint cytology with that of histology diagnosis in case of Ovarian Neoplasm . As there are only a few reports describing its accuracy and validity of intraoperative cytology. [16][17][18] The present study shows touch/ imprint cytology consists Negative for malignancy 89.1% and Positive for malignancy 10.9%. Whereas, Melies M et al. in their study showed 81.8% patients were negative and 18.2% patients were positive while in border line all cases were positive and in malignant group 11.9% patients were negative and 88.1% patients were positive. 16 Nagai et al. examined the imprint cytology and reported that the accuracy of intraoperative imprint cytology was 87.1% for benign, 30% for borderline, and 83.6% for malignant tumors. 19 Jain R et al. in the study about role of intraoperative cytology showed diagnostic accuracy of 95.60%. 20 Sushma and Panicker in their study showed 96.4% diagnostic accuracy in surface epithelial lesions, almost 100% accuracy in identifying germ cell tumors and 98.5% accuracy in categorizing sex cord stromal tumors. 21 Melies et al. in 2018 intraoperative imprint cytology study found sensitivity was 84.85% and specificity 100%. 16 In the study of imprint cytology of ovarian neoplasms done by Tushar, et al. the sensitivity and specificity were 93% and 92% respectively. 22 Nadji, et al. had a sensitivity and specificity of 96.4% and 92% respectively in their study on cytology of ovarian neoplasms. 23 In our study, overall diagnostic accuracy of touch imprint was 99% with sensitivity 100% and specificity was 91.67 percent.  16 Mature cystic teratoma, Immature teratoma and Yolk sac tumor are the germ cell tumors that we came across in our study. Diagnostic accuracy is 100% in our study and our findings are supported by the study done by Shahid et al. 24 , Khunamornpong and Siriaunkgul 26 and Jain R et al. 20 which also showed 100% diagnostic accuracy of cytological examination in detecting germ cell tumors.
Clear cell carcinoma was another epithelial malignant tumor that we came across in our study. Most of the comparing cytology studies with histopathology showed 100% accuracy like in study done by Azami S et al. 25 also showed 100% accuracy in their study.
Metastasis adenocarcinoma was one of the false negative cases in imprint cytology in our study, whereas in the study of Azami S, Aoki Y, Iino M, et al. 25 and Sardar K et al. 27 showed true positive in their study for the metastasis malignant tumor.
The touch/ imprint cytology is a good compliment to histopathology. Facility where advanced rapid intraoperative technology is not available, IOC plays very important roles in rapid preliminary diagnosis.

CONCLUSIONS
Imprint cytology plays a significant role in the quick diagnosis of the lesion. It is less expensive, simple, fast and reliable method for diagnosis of malignant ovarian neoplasms. And it is better option where there is no available facility of technology like frozen sections. It can act as a good complement to histopathology and can be of benefit for rapid preliminary diagnosis and surgical management planning.