This comparative cross-sectional study was carried out in the Department of Pathology at DM Wayanad Institute of Medical Science, Wayanad, Kerala, India, for over a period of 18 months from January 2016 to June 2017. Institutional Ethical Committee approval was obtained and a total of 210 patients with the indication of endometrial sampling were evaluated. Detailed clinical history inclusive of laboratory investigation reports and radiological findings were recorded from the institutional records.

The AUB patients with no obvious cervical lesions and without any haematological disorders were included in the study. Patients with lower genital tract/pelvic infections, known cases of cervical stenosis, cervicitis, premalignant and malignant cervical lesions or pregnancy were excluded from the study.

After getting informed consent pipelle endometrial sampling was performed followed by dilatation and uterine curettage. Through, undilated cervix the pipelle device was introduced into uterine cavity without anaesthesia. The piston is fully withdrawn to create suction and the device is rotated to get a sample which was collected in formalin bottle. Endometrial sample was sent for histopathology.

The endometrial samples obtained by two different methods were introduced in 10% formalin, processed by routine histopathological techniques and paraffin blocks were prepared. From each block about 3-4 μm sections were cut, mounted, dewaxed and stained with H&E. The slides were submitted to detailed microscopic examination and were evaluated independently. The microscopic findings and histopathological diagnosis in each case by pipelle aspiration techniques and curettage were separately recorded and comparative analysis undertaken.

Data analysis was performed by using IBM Statistical Package for the Social Sciences (SPSS) software version 21.0. Sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and diagnostic accuracy were calculated.

All 210 endometrial samples were evaluated in the study. The mean age of the studied population was 44.6 years (Standard deviation 7.04; age ranged between 31 and 66 years). Majority of the patients (131) were perimenopausal. Menorrhagia was the most common presenting complaint seen in 116 cases (55.24%), followed by metrorrhagia in 48 (22.86%) cases, Polymenorrhea in 28 (13.33%) cases and postmenopausal bleeding in 18 (8.57%) cases.

Pipelle sample was found inadequate for evaluation in 10 cases while all the 210 D and C samples were adequate for histopathological examination. A sample was labelled as inadequate by the histopathologist when no endometrial tissue were present [Table/Fig-1]. Comparison of histopathological findings between two endometrial sampling methods is shown in [Table/Fig-2].

In the present study, of the 85 cases reported as endometrial hyperplasia by pipelle method, 77 cases showed positive correlation with D and C [Table/Fig-3], the remaining cases turned out to be disordered proliferative (5), secretory endometrium (1), hormone related changes (1) and atrophic endometrium (1). These cases were considered as false positives for endometrial hyperplasia. Among seven cases diagnosed as atypical endometrial hyperplasia by pipelle method, D and C concurred with six cases and the case diagnosed as atypical hyperplasia with suspicion of invasion was proved to be endometrial carcinoma by D and C [Table/Fig-4]. All the seven cases diagnosed as endometrial carcinoma by pipelle method were found to be in agreement with D and C [Table/Fig-5].

[Table/Fig-3]:

Photomicrograph of pipelle sample showing endometrial hyperplasia without atypia (10X and 40X [inset], H&E staining).

[Table/Fig-4]:

Photomicrograph of pipelle sample showing endometrial hyperplasia with atypia (H&E staining, 10X).

[Table/Fig-5]:

Photomicrograph of pipelle sample showing endometrial carcinoma, villoglandular type (black arrow) (H&E staining, 10X).

Histopathological examination of D and C samples detected 37 cases of disordered proliferative endometrium while pipelle method detected 30 cases, a diagnosis of endometrial hyperplasia was made on five cases and two cases of pipelle were found inadequate for evaluation. Of the eight cases diagnosed as hormone related changes by D and C, pipelle method detected five cases, one case was diagnosed as endometrial hyperplasia and two cases were opined to be inadequate for a definite opinion by pipelle method. The diagnosis of atrophic endometrium was made on 10 cases by D and C sampling, out of which, pipelle detected six cases, three cases were found inadequate for reporting and one case was diagnosed as endometrial hyperplasia by pipelle.

In the present study, pipelle sampling had 100% sensitivity and 100% NPV in detecting endometrial hyperplasia, atypical endometrial hyperplasia and choriocarcinoma. It showed 100% specificity and 100% PPV in diagnosing endometrial carcinoma, disordered proliferative and proliferative endometrium. The sensitivity rate in diagnosing atrophic endometrium and hormone related changes were found to be 60% and 62.5% respectively. The overall diagnostic accuracy rate of pipelle sampling was 98.09% [Table/Fig-6].

Endometrial sampling is an indispensable and an outstanding tool in the assessment of underlying pathology in patients with AUB [8,9]. Pipelle endometrial sampling yields good accuracy rate when reported by an experienced pathologist. Pipelle procedure requires less than a minute to perform and produces hardly any post procedure bleeding or patient discomfort.

The main purpose of endometrial sampling is early detection of endometrial hyperplasia and carcinoma. Endometrial sampling by pipelle method is an outpatient procedure and its advantages include low cost, minimal risk for the patient, non requirement for anaesthesia and least discomfort or pain [10]. However, the procedure yields sufficient sample adequate for the interpretation by a pathologist. The probability of processing an adequate sample is even higher when the endometrial thickness is assessed by prior ultrasound imaging as more than 5 mm [11,12].

Pipelle endometrial sampling scores over D and C in its simplicity as it can be performed without anaesthesia or analgesia during routine pelvic examination. In the present study, pipelle sampling was done followed by D and C sampling in order to maintain the synchrony in sampling which is mandatory for a comparative analysis.

In the present study, despite the fact that pipelle method had low sensitivity in detecting atrophic endometrium and disordered proliferative endometrium, it showed high NPV (98.04% and 96.1% respectively) and high accuracy rate (98.01% and 96.67% respectively). These findings are in accordance with the study done by Aron T et al., which also showed that pipelle endometrial sampling method had an accuracy rate of 95.5% and NPV of 98.8% in diagnosing atrophic endometrium [13].

Chaudry A and Javaid M, and Behnamfar F et al., had concluded in their studies that pipelle technique is an accurate and a widely accepted endometrial sampling technique in comparison with sampling by D and C [14,15]. The obtained observation are in concurrence with these studies as the sensitivity, specificity and accuracy rates for pipelle sampling were almost on par with the D and C sampling in the assessment of endometrial lesions.

Clark TJ et al., recommended in their study that, due to the moderate accuracy rates observed in diagnosing endometrial hyperplasia on pipelle sampling, additional and supportive assessment should be supplemented along with pipelle sampling [16].

Dijkhuizen FP et al., and Rachamallu L et al., observed in their meta analysis that pipelle endometrial sampling is an effective diagnostic tool in diagnosing atypical hyperplasia and carcinoma [17,18]. Studies done by Chandrashekar N et al., and Patil P et al., showed that pipelle method had a specificity rate (99% and 98% respectively) and accuracy rate (98% and 99%) respectively in diagnosing endometrial carcinomas, present findings showed good congruence with these studies [6,19].

There are few limitations concerning this study. This was single hospital based study with small sample size, so results of this study cannot be generalised. Taking this study as reference point, future multicentric research with larger sample size involving higher number of postmenopausal cases can be planned.

Pipelle endometrial sampling is a non invasive outpatient procedure with diagnostic accuracy rate paralleling that of D and C sampling. Clinicians and patients find it more convenient and acceptable technique. Coupled with its additional benefits of high sampling adequacy, it is not far behind in becoming an unequivocal and indispensable tool in the diagnosis of endometrial lesions.