Diagnostic Utility of Ultrasound-Guided Fine-Needle Aspiration Cytology in Gall Bladder Lesions: An Experience from a Tertiary Care Cancer Center in Eastern India.

INTRODUCTION: Gallbladder cancer (GBC) is the most common malignancy, representing 80-95% of biliary tract cancers. Although ultrasonography-guided fine-needle aspiration cytology (USG-FNAC) has emerged as an effective diagnostic the tool for the precise diagnosis of gallbladder lesions, data on its diagnostic utility and cytomorphological categorization of gallbladder lesions are lacking. AIMS: To study the diagnostic utility of USG-FNAC in gallbladder lesions.
MATERIALS AND METHODS: This study was the conducted prospectively on patients who came with clinical and radiological evidence of gallbladder space-occupying lesion and then advised to USG-FNAC over 2 years and 6 months from January 2018 to June 2020.
RESULTS: A total of 314 cases were included. The mean age was 56 years, with a range of 17-88 years. Women predominated over men (Male:Female = 1:2.3). Primary adenocarcinoma of the gallbladder was most common. On cyto-histological correlation, the sensitivity, specificity, and diagnostic accuracy of USG-FNAC of gallbladder lesions were found to be 98.82, 87.23, and 96.3%, respectively.
CONCLUSION: The USG-FNAC of gallbladder lesion was found to be an easy, quick, cost-effective, and presumptive diagnostic procedure. It should be opted as an initial preoperative diagnostic modality in high incidence areas to avoid inappropriate management with unnecessary morbidity and cost. Moreover, a close cytological examination of the architectural pattern and the cytomorphological features would help in the sub-typing and prognosticating the tumor. Copyright:

INTRODUCTION

Gallbladder cancer (GBC) is the most common malignancy, representing 80–95% of biliary tract cancers.[1] According to the Globocon 2018 data, the rate of new gallbladder cancer cases were found to be 2, 19,420 and death 1,65,087.[2] The high frequency of similar mortality rates were reported from Chile, Peru, Nepal, India, Bolivia, Bangladesh, Japan, Korea, and the Czech Republic.[3] Despite its first description by Maxmillan de Stol in 1777, the overall prognosis has remained dismal with 5-year survival rate of 5–10% due to late diagnosis and ineffective treatment of this disease.[45] The radical resection approach is the best available therapeutic option for long-term survival, but the majority of patients presenting in an advanced stage are inoperable.[6] Although radiological assessment including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) are being used as an initial preoperative diagnostic modality, in some cases, they create problems leading to inappropriate surgery.[7] In this regard, the USG-FNAC approach is a safe, quick, and cost-effective preoperative diagnostic tool for precise diagnosis of gallbladder lesions.[8910111213] However, this the procedure is still avoided as a first-line diagnostic tool at many health care centers due to lack of facilities, expertise, and the reluctance of the concerned clinician because of fear of procedure-related complications and low diagnostic accuracy. Hence, the diagnostic utility, standard cytological terminology, and nomenclature systems used for gallbladder lesions on FNAC are lacking.[14] The purpose of this study was to find out the diagnostic utility of USG-FNAC in patients with gallbladder lesions as significant number of GBC cases are reported as late-stage presentation in Odisha and no study has been systematically conducted on it. We also attempted to find out the geographical and seasonal variation of gallbladder cancer in Odisha.

MATERIALS AND METHODS

This study was conducted prospectively in patients who presented with clinical and radiological evidence of gallbladder space-occupying lesions and were subsequently subjected to USG-FNAC over a period of 2 years and 6 months from January 2018 to June 2020.

Inclusion criteria

Patients of all ages and sex with pathological (Cytology and/histopathology) evidence of primary gallbladder diseases were included.

Exclusion criteria

Patients having altered PT and aPTT (double than normal), secondary gallbladder carcinoma cases, and inadequate aspirate cases were excluded from this study.

The Institutional ethics (IEC) committee approved this study protocol. Patient consent was taken prior to the aspiration.

During aspiration, the 22-gauge, 90-mm spinal needle was inserted into the abdomen at the appropriate site followed by constant monitoring of the needle tip under real-time ultrasound guidance. Once the needle tip hit the target area, a 10-mL syringe was mounted on the needle. The needle was quickly moved back and forth multiple times in different directions with continuous suction of the syringe until the requisite sample was collected. The needle was withdrawn and the aspirated material was smeared on pre-cleaned glass slides and air-dried. The remaining aspirates were subjected to cell block preparation. One of the smear was wet fixed with alcohol for pap staining. A post - procedure scan was performed to detect any immediate complications.

At the time of microscopic observation, the smears were categorized into two group with adequate and inadequate or nonconclusive. The presence of five or six groups of cells deemed to represent the lesion was considered as adequate for reporting. Cases with inadequate sampling were subjected to second USG-FNAC in another setting. The microscopic examination was done by two independent pathologists as per WHO guidelines (2010).[15] Cytodiagnosis was confirmed by laparoscopic or open biopsy diagnosis but in advanced stage cases where the disease had invaded the liver tissue, duodenum, omentum and regional lymph nodes with a clinical presentation of jaundice, gross ascites and those who were unfit for surgical resection, cell block diagnosis was considered as an adjunct to cyto- diagnosis.

To understand the geographical variation in GBC, a district-wise distribution of cases was done. Similarly, on seasonal variation, the months were grouped according to seasons such as pre-monsoon (March, April, May), monsoon (June, July, August, September), post-monsoon (October, November), and winter (December, January, February).

Statistics

The results were presented in numbers and percentages. The sensitivity, specificity, and diagnostic accuracy of adequate aspiration were calculated. All the analyses were carried out by using Microsoft excel 2007.

RESULTS

A total of 314 cases underwent USG-FNAC, among which females predominated over male with male-to-female ratio 1:2.3 but in GBC the male to female ratio was 1:1.9.The mean age in GBC was 55.43 years.

While for analyzing geographical distribution, it was observed that maximum number of cases [117 (37.26%)] were from coastal districts rather than hilly districts [32 (10.19%)] [Figure 1]. Seasonal variation in gallbladder cases showed two peaks-one in pre-monsoon followed by winter [Figure 2].

Figure 1

Geographical distribution of gallbladder carcinoma cases in Odisha

Figure 2

Seasonal variation of gallbladder carcinoma cases in Odisha

The majority of cases were found to be neoplastic lesions of which adenocarcinoma of the gallbladder predominated [261 (97.75%)] [Table 1].

Table 1

Age and sex-wise distribution of gallbladder neoplastic and nonneoplastic lesions

Final Diagnosis	Mean ± SD (Age)	Total Numbers (%)	M:F
Adenocarcinoma gallbladder	55.47 ± 11.97	259 (82.48)	1:2
Squamous cell carcinoma gallbladder	56.66 ± 14.22	6 (1.91)	1:1
Mucinous adenocarcinoma gallbladder	55.43 ± 9.39	2 (0.63)	1:1
Acute cholecystitis	56.06 ± 11.13	16 (5.09)	1:1
Chronic cholecystitis	58.66 ± 10.45	19 (6.05)	1:1
Xanthogranulomatous cholecystitis	58.08 ± 9.41	12 (3.82)	1:3
Total (%)	56 ± 9.54	314 (100)	1:2.3

M:F = Male:Female

The mean age of malignant cases in male was found to be 58.32 ± 10.05 years, whereas, in females, it was found to be 53.92 ± 8.79 years.

During an ultrasonographic evaluation, the lesions of the gallbladder presenting with growth was 228 (72.61%) cases while focal or diffuse wall thickening without mass lesions was observed in 86 (27.38%) cases. In 144 (45.85%) cases, the radiological features were suggestive of gallbladder carcinoma with liver metastasis.

In this study, adequate smears were obtained in 286 (91%) cases. Repeat FNAC was done in 28 (8.91%) cases, which were inadequate in the first puncture. Out of these repeat cases, chronic cholecystitis, acute cholecystitis, xanthogranulomatous cholecystitis, and adenocarcinoma were found in 13, seven,two and six, respectively. No major complications were observed during aspiration or post-aspiration period. The Cytomorphological diagnosis of 314-gallbladder lesion shown in [Figure 3].

Figure 3

Distribution of gallbladder lesions diagnosed by USG-FNAC

In cytology, there were 131 (41.71%) cases found to be primary gallbladder carcinoma with liver metastasis among which cell block adjunct to cytodiagnosis was observed in 33 (25.19%) cases. In 98 (74.8%) cases, the diagnosis was confirmed based on clinical presentation with radiological and cytomorphological features as histopathological confirmation was not possible. These cases were subjected to neoadjuvant chemotherapy and palliative procedures like stenting to relieve the jaundice. Cyto-histo diagnosis correlation was done in 216 (68.78%) cases among which surgical resection was done in 183 cases (84.72%) [Table 2].

Table 2

Cyto-histo diagnosis correlation of gallbladder lesion

USG FNAC Diagnosis	No	Histopathology	Diagnosis
Adenocarcinoma	139	137	Adenocarcinoma
		2	Xanthogranulomatous cholecystitis
Squamous cell carcinoma	6	6	Squamous cell carcinoma
Mucinous adenocarcinoma	2	2	Mucinous adenocarcinoma
Acute cholecystitis	17	16	Acute cholecystitis
		1	Xanthogranulomatous cholecystitis
Chronic cholecystitis	22	18	Chronic cholecystitis
		2	Adenocarcinoma
		2	Xanthogranulomatous cholecystitis
Xanthogranulomatous cholecystitis	4	4	Xanthogranulomatous cholecystitis
Suspicious of carcinoma	26	19	Adenocarcinoma
		2	Adenocarcinoma with low-grade dysplasia
		1	Adenocarcinoma with xanthogranulomatous
		3	Xanthogranulomatous cholecystitis
		1	Chronic cholecystitis

The true positive, true negative, false positive, and false negative values of cytology was found to be 167, 41, six, and two respectively. Therefore, the sensitivity, specificity, and diagnostic accuracy of USG-FNAC of gallbladder lesions were 98.82, 87.23, and 96.3%, respectively.

DISCUSSION

GBC is less common in developed countries, while its incidence is found to be the highest in India with a striking geographical variation. Cachar, Delhi, Kamrup, Dibrugarh, Kolkata, and Sikkim were found to be the high-risk regions. The time trends and pattern of GBC have striking differences even within the state. In states with low risk of GBC, the rates of GBC were higher only in metro cities (Mumbai, Pune, and Bangalore).[15]

The basis of geographical variance possibly resides in differences in environmental exposure, lifestyle factors, diet, intrinsic genetic predisposition, and limited access to health care.[1516]

Unlike other regions, in Odisha, a significant numbers of gallbladder cancer were reported with late-stage presentation.

As significant geographical variation was observed in this study showing more cases in coastal districts, a large-scale study in our high- and low-risk regions of GBC could be useful to understand its etiology by which preventive measures of this fatal disease can be established.

Previous studies present the seasonal variation in different types of cancer mortality which might be related to season specific factors such as infections, cold, diet, and environmental pollutants.[17181920]

We observed a seasonal variation in gallbladder diseases and observed a higher incidence in pre-monsoon and winter, but we could not identify the exact reason. However, since majority of patients were from coastal areas and were dependent on agriculture for their livelihood and relatively free from agricultural activities during this time, they might have concentrated their attention for their health and came for evaluation during this period. Further descriptive studies in relation to seasonal variation may be useful for elucidating, how the seasonal factors impact gallbladder diseases.

GBC is the only digestive system cancer that is more common in women than men.[21] In this study, the male to female ratio of GBC was 1:1.9, whereas in other Indian studies, it was found to be 1:4.2.[8]

The female hormone estrogen is found to be the main factor contributing to increasing GBC in women as it increases the saturation of cholesterol in bile, thus increasing the risk of gallstone formation, which is believed to be the primary culprit behind the greater risk of gallbladder cancer.[22]

In our study, the mean age of GBC was found to be 55.43 years, whereas in other studies, the mean age was found to be 45 years.[13] In India, GBC usually affects younger patients in the fifth and sixth decade of life in contrast to the west.[16]

In this study, the lesions of the gallbladder presenting with growth was 228(72.61%) cases while focal or diffuse wall thickening without mass lesions were observed in 86(27.38%) cases.[23] Unlike other previous studies, the primary indication of USG-FNAC of gallbladder was diffuse mural thickening/single/multiple lesions detected by USG [Figure 4a]. During or post-aspiration, no major complications were reported in any of the 314 cases, which were consistent with the previous studies.[1124]

Figure 4

(a) Growth in the lumen of gallbladder and wall thickening. (b) Adenocarcinoma of gallbladder (H and E, ×400). (c) Squamous cell carcinoma of gallbladder (PAP, ×400). (d) Xanthogranulomatous cholecystitis (H and E, ×400)

In this study, from a single puncture, the adequate smears comprised of 91%, which was similar to the study done by Rana et al.[10], while in another study, the adequacy rate was comparatively low (62.7%).[12]

The rate of inadequacy was 8.91%, which was almost comparable to other studies in which the inadequacy rate ranged from 7.8 to 10.2%.[91013]

In another study done by Handa et al.[25] the maximum number of inadequate smears (70%) were reported to cases of focal or diffuse wall thickening without an obvious mass lesion. In our study, all inadequate smears obtained from the first puncture (8.91%) were found to be adequate during repeat USG-FNAC.

Unlike other studies, adenocarcinoma was found to be the most common malignant type (83%) on cytosmear analysis as the smears show mostly acini and sheets with columnar to rounded cells showing nuclei with vesicular chromatin and prominent nucleoli in the inflammatory background [Figure 4b].[891113]

Papillary adenocarcinoma has been considered a good prognostic subtype as described previously by Armed Forces Institute of Pathology.[8]

In this study, none of the cases showed, predominantly true papillary fragments either in cytomorphology or histomorphology. So, these cases were included in adenocarcinoma not otherwise specified, whereas in other studies done by Yadav et al.[13] and Bhartiya et al.[8], the incidence of cytological diagnosis of papillary adenocarcinoma cases were found to be 8% and 3.38%, respectively.

Similarly, mucinous adenocarcinoma is a rare histological subtype of gallbladder carcinoma and presents at an advanced stage with a poor prognosis compared to the conventional gallbladder carcinoma. It comprised of 0.76% in our study, whereas in other studies, it was found to be 3.3–6.1%.[891326]

In this study, pure squamous cell carcinoma (SCC) comprised of 1.91%. Other authors also observed similar trends.[8913]

According to the literature review, it was observed that SCC of gallbladder most often clinically mimics acute cholecystitis; preoperative diagnosis is often missed and, most often, it presents in advanced stage with infiltration into the liver or adjacent structures.[27]

In our study, all pure SCCs of gallbladder cases were diagnosed presumptively in cytology as the smear showed polygonal cells with a hyperchromatic-elongated nucleus with good number of dyskeratotic cells [Figure 4c]. None of the cases presented with liver or adjacent organ infiltration.

Cytological features were suspicious or suggestive of carcinoma in 26 (8.28%) cases, that was consistent with the study done by Kumar et al.[11] In this study, suspicion of malignant gallbladder cancer cases were considered as positive in cytology as cytomorphology demonstrated mild cellular pleomorphism among groups of epithelial cells and occasional atypical cells along with inflammatory cells. In these cases, radiological diagnosis also supported the cytodiagnosis. Histopathological correlation was done in all the cases.

Among suspicious of malignancy on USG-FNAC, xanthogranulomatous cholecystitis was found to be false positive. This finding was in agreement with the study done by Rana et al.[10]

Yoshida et al.[28] had also studied the clinical factors in order to differentiate xanthogranulomatous cholecystitis from carcinoma. They found that findings of a non-visualized gallbladder on cholangiography and cholelithiasis in combination with an operative aspirate of pus or nothing from within the gallbladder favour the diagnosis of an xanthogranulomatous cholecystitis over carcinoma.

In this present study, four xanthogranulomatous cholecystitis were correctly diagnosed by cytomorphology as the smear showed a regular arrangement of epithelial cells in sheets and mixed inflammatory cell component with a large number of foamy histiocytes and surrounding capillary blood vessels [Figure 4d].

In our study, cyto-histo concordance between malignant cases was found to be 96.53%, whereas in other studies, it was reported to be 94.4%.[9]

In our study, two chronic cholecystitis cases turned out to be adenocarcinoma in histology. So, the overall false-negative case was 4.65%, whereas in other studies done by Krishnani et al.[12], 12.01% of carcinoma cases were missed.

In this study, the diagnostic accuracy of USG-FNAC was in agreement with other studies like Kumar et al.[11] (95.3%), and Yadav et al.[13] (96.8%).

The USG-guided FNAC of gallbladder lesions was found to be an easy, quick, cost-effective, and presumptive diagnostic procedure. It should be opted as an initial preoperative diagnostic modality in a high-incidence area to avoid inappropriate management with unnecessary morbidity and cost. Moreover, a close cytological examination of architectural pattern and the cytomorphological features would help in sub-typing and prognosticating of the tumor. Working coordination between clinicians, sonologists, and cytopathologists with adequate sampling, experience, caution in interpreting the aspirate, and a close working relationship is essential for its success.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.