Real time ultrasound guided fine needle aspiration cytology of intra-abdominal and intra-pelvic masses- synergistic approach of radiologist and cytopathologist for better cellular yield

Introduction

Fine needle aspiration cytology (FNAC) is relatively less painful, easily performed, rapid reporting, less expensive, highly sensitive and specific for superficial lesion as well as deep seated intra-abdominal and intra-pelvic masses.1, 2, 3, 4, 5, 6, 7 Radiological guidance helps in locating the intra-abdominal masses especially the solid component in cases with large mass with both solid and cystic components. The diagnosis given by FNAC may at times substitutes for surgical procedures like diagnostic laparotomy.5 Image guided FNAC sampling can be done by either ultrasound or computerized tomography scan (CT).7, 8 As compared to CT scan, real time imaging by ultrasound is better as there is no ionizing radiation, less complication, faster, less costly9, 10, 11 and needle tip can be easily visualized and manipulated in any direction saving the vital structures.11, 12 (Figure 1). Diagnosis from the aspirated material aids in screening benign cases and at times helps the clinician in deciding the best line of management. Despite the obvious advantages, debate and controversies continues for its use in diagnosis of ovarian neoplasms.

Figure 1

Real time ultrasound guided FNAC from liver nodule showing needle tip in the target lesion.

Aims and Objectives

The main aims and objectives of the study were-

Material and Methods

The present study is a retrospective study of 161cases reported during the period of 1^st July 2018 to 31^st December 2019 in a tertiary cancer center. The data were retrieved from diagnosed cases of intra-abdominal and intra-pelvic masses which were evaluated by cytology with real-time ultrasonography. Ultrasound guided FNAC from other sites and failure to reach the target mass due to overlying solid organs were excluded. Coagulation and screening profiles were routinely done before the procedure. FNAC were done only for patients with normal coagulation profile. Special precautions were taken for HIV, HCV and HBSAg positive cases, as per the NABH guidelines. Lumber puncture needles of various sizes were taken for various abdominal organs. For ovary and other pelvic masses-18-gauge, liver/gall bladder- 22-23 gauge and kidney-23-gauge spinal needles were taken respectively. All samples were obtained by per abdomen real-time ultrasound guided aspirations under aseptic precautions with aspiration done by 5 ml or 10 ml disposable syringes. Generally, 1-2 aspirations were done. If required, repeat aspirations were done later. Aspirations up to 4 times were done.

Aspirates were smeared on the slides and wet- fixed in 95% alcohol fixative immediately and in cases of serous or mucinous fluids, smears were made from the sediments obtained from centrifugation of fluid in cytospin. Haematoxylin and Eosin (H&E) and Pap stains were done as routine. Rapid H&E and May Grunwald Giemsa (MGG) stains were done occasionally. Special stains like Zeil Neelson stains for Acid fast bacilli were done as and when Koch's etiology was suspected. In cases of pus aspiration, collection was done in sterile containers and sent for culture and sensitivity.

Histopathological correlation was done on needle core biopsy and surgically operated cases.

Chart 1

Flow chart showing the procedure done for real time ultrasound guided FNACs of intra-abdominal and intra-pelvic masses

Results

The age group varied from 18 years to 76 years with female: male ratio of 2:1. Among 161 cases of intra-abdominal lesions- ovary- 73 cases, liver- 45 cases, kidney- 27 cases, gall bladder- 07 cases, Colon (caecum and descending colon)- 03 cases and pelvis mass- 03 cases, pancreas- 02 cases and retroperitoneal lymph node- 01 case were studied. The cases were categorized into non-neoplastic and neoplastic. The neoplastic lesions were further divided into benign and malignant. (Table 1) Ultrasound guided aspirates were conclusive for reporting in 145 cases, inconclusive for reporting in 10 cases and acellular/ haemorrhagic in 06 cases. Inconclusive cases were those neoplastic cases where definitive diagnosis of benign/ borderline/malignant could not be interpreted even after repeating the aspirations. Most inconclusive cases were from ovary- 08 cases and liver /kidney- 01 case each. All acellular/ haemorrhagic aspirates were from kidney- 05cases. (Table 2)

Kidney aspirations were done with 23 gauge spinal needles as they are highly vascular. Aspirations of these kidney masses were done with minimal negative pressure to avoid excess blood, which dilutes the cells and hinders reporting.

For tumours with solid and cystic component, localization of the solid component was done. In cases of ovarian cyst with solid and cystic component, malignant cell yield was better if aspirated from solid area. In cases of deep seated solid areas best effort was given to reach the target site. In one case of recurrent carcinoma ovary, trans-abdominal approach did not yield good sample as the lesions was located deep in pelvis. Transvaginal approach was attempted in this case for better localization of solid area and yield. (Figure 3)

Out of 73 cases of ovary, non-neoplastic- 03 cases, benign- 10 cases, malignant- 52 cases and inconclusive for benign/ malignant- 08 cases were studied. (Table 3) Three cases of non- neoplastic ovary aspirates were pus. These were collected in sterile containers and sent for culture and sensitivity. One case was treated medically. Laparotomy was done for two cases and tubo-ovarian mass were excised. These were confirmed by histopathology. Among benign cases of ovary, brown color fluid was aspirated in three cases and showed features of endometriotic cyst and were correlating with the histopathology findings. Other 06 cases of benign serous/ mucinous cystadenomas were also confirmed by histopathology. (Figure 4)

Six cases of carcinoma ovary were malignant germ cell tumour. Serum β HCG, AFP and LDH and immunohistochemistry were done for each cases. (Table 4)

In the present study liver masses were 45 cases, out of which there were chronic liver disease-01 case, benign (hemangioma)-04 cases, malignant (Hepatocellular carcinoma-16 cases and Cholangiocarcinoma- 02 cases)- 18 cases, metastatic deposits- 20 cases, inconclusive- 01 case and acellular- 01 case. (Table 3) Metastetectomy of one case with single liver deposit was done. It was a case of oligometastasis from adenocarcinoma rectum. Histopathology findings were correlating with that of cytology. (Figure 5)

In the present study kidney masses were 27 cases with malignancy in 21 cases, inconclusive in 01 case and acellular in 05 cases.(Table 3 ) Out of 27 malignant cases, 26 cases were reported as renal cell carcinoma and 01 case was reported as transitional cell carcinoma. On histopathology of nephrectomy specimens, clear cell renal cell carcinoma- 22 cases and chromophobe renal cell carcinoma- 01 case, papillary renal cell carcinoma- 01 case, and one case was reported as benign pheochromocytoma were seen. One case of transitional cell carcinoma arising from the renal pelvis and extending to renal cortex was non-operable. (Figure 6) Acellular aspirates were seen in 05 cases, where repeat aspirations also could not yield adequate material.

In the present study gall bladder masses were 07 cases. Three cases were in stage IV and four cases were in stage I. Radical cholecystectomy was done for the cases in stage I. Histopathology findings were correlating with that of cytology. (Figure 7 a).

One case of retroperitoneal lymph node was reported as Non-Hodgkin lymphoma on cytology and histopathology and was categorized as diffuse large B-cell lymphoma on immunohistochemistry. (Figure 7 b).

One old operated case of carcinoma stomach presented with pancreatic mass. Guided FNAC followed by core biopsy was reported as adenocarcinoma. It was confirmed as metastasis from stomach on immunohistochemistry. (Figure 7 c).

In the present study colon masses was aspirated in two cases and reported as adenocarcinoma on cytology. (Figure 7 d). Both cases were non-operable, stage IV disease.

One case of squamous cell carcinoma with ilio- psoas collection was aspirated under ultrasound guidance.

One case of post radiotherapy carcinoma vault, presented with pelvic mass. Real time aspiration was done and reported as recurrent squamous cell carcinoma deposit.

Out of 161 cases surgery was done for 110 cases. Histopathology and cytology diagnosis were correlated. Diagnosis for histopathology and cytology were correlating in 108 cases. One case of fibroma ovary was given as malignant on cytology and one case of renal benign pheochromocytoma was reported as carcinoma on cytology. (Table 5)

Figure 2

CT scan image showing large pelvic mass with cystic (C) and small deep seated solid component (S). Aspiration was done by transvaginal approach.

Figure 3

Cytology and corresponding histopathology from ovary; (a) Benign mucinous ovarian cystadenoma- Sheets and clusters of small, round epithelial cells and small relatively uniform nuclei. (H&E, 25x). INSAT- Microphotograph of histopathology of the corresponding ovary cyst wall,

(b) Endometriotic cyst- Haemosiderin laden macrophages in the background of altered blood. (H&E, 25x). INSAT- Microphotograph of histopathology of the corresponding ovary,

(c) Teratoma ovary- Keratin and hair follicle. (Pap, 25x). INSAT- Microphotograph showing keratinized squamous cells,

(d) Mixed Germ cell ovarian tumour (Dysgerminoma-95% and Embryonal carcinoma-05%)- Poorly cohesive malignant cells, fragile cytoplasm, vesicular nuclei with prominent nucleoli and nuclear smudging with few lymphocytes. (Pap, 40x). INSAT- Microphotograph of histopathology of the corresponding ovary, (e) Mucinous ovarian cystadenocarcinoma- Clusters of pleomorphic malignant glandular cells with a background of mucus. (Pap, 40x), (f) Serous ovarian cystadenocarcinoma- Papillary tissue fragment of crowded atypical glandular cells, scanty pale cytoplasm, large overlapping nuclei. (Pap, 40x).

Figure 4

Cytology and corresponding histopathology (if available) from liver; (a) Hepatocellular carcinoma - Cellular smears with irregular large fragments, clusters and dispersed cells with capillaries transgressing clusters of tumor cells (H&E, 25x).

(b) Hepatocellular carcinoma - Neoplastic cells forming pseudo acini (yellow arrow),

(c) Hepatocellular carcinoma - Intracytoplasmic bile pigment,

(d) Hepatocellular carcinoma - Cells with macronucleoli,

(e) Hepatocellular carcinoma - Intranuclear cytoplasmic inclusion,

(f) Liver metastasis of adenocarcinoma showing cytoplasmic vacuoles (red arrow). (H&E, 40x) and

(g) Liver metastasis of gastrointestinal stromal tumor- Cohesive cluster of haphazardly arranged spindle cells showing mild anisoncleosis and tapered cytoplasm (Pap, 40x).

Figure 5

Cytology and corresponding histopathology (if available) from kidney; (a) Renal cell carcinoma, clear cell type- Loosely cohesive cell clusters, abundant fragile, vacuolated cytoplasm, mild pleomorphic small nuclei, inconspicuous nucleoli with few endothelial cells. (H&E, 40x) and INSAT- Microphotograph of histopathology of the corresponding kidney,

(b) Renal cell carcinoma, chromophobe type- Clustered cells, majority with abundant granular and vacuolated cytoplasm, some much smaller cells, moderate anisokaryosis, cytoplasm condensed peripherally, perinuclear pale area. (H&E, 40x) and INSAT- Microphotograph of histopathology of the corresponding kidney, (c) Papillary renal cell carcinoma- Clustered small epithelial cells, mainly basophilic, with low-grade uniformly small nuclei (H&E, 40x), and INSAT- Microphotograph of histopathology of the corresponding kidney, (d) Transitional cell carcinoma, renal pelvis- Cells dispersed singly with a nucleated globular body and a unipolar non tapering cytoplasmic process the ends of which are bulbous or flattened. These cells are called CERCARIFORM cells. (Pap, 40x)

Figure 6

(a) Adenocarcinoma (gall bladder)- Well-differentiated adenocarcinoma with pleomorphic hyperchromatic nuclei and mucin in the background. (Pap, 40x), (b) Non- Hodgkin lymphoma -Diffuse large B-cell (retroperitoneum)- Large atypical lymphocytes with pale nuclei, scanty cytoplasm and multiple nucleoli (H&E, 40x),

(c) Adenocarcinoma pancreas, metastasis from stomach (H&E, 25x) and (d) Adenocarcinoma (caecum)- Tumour cells showing minimal cytoplasm, high nucleo-cytoplasmic ratio, hyperchromatic and pleomorphic nuclei. (H&E, 40x).

Discussion

Intra-abdominal and intra-pelvic masses are well visualized by radiological techniques. But these techniques fail to delineate benign and malignant lesions.10 An accurate morphological diagnosis is essential for planning definitive treatment and staging of tumours. FNAC of intra-abdominal non-palpable masses cannot be performed blindly. Radiological assistance by ultrasound/ CT is needed for these lesions. Ultrasound is preferred over CT as it is rapid, less expensive, without ionizing radiation and does not require injection of contrast medium.9, 10, 11 (Table 6) The procedure is easy to perform, easy to visualize the forwarding tip of spinal needle and easily repeated when necessary. 11, 12 The diagnostic yield of USG guided aspiration is better than CT scan guided aspiration. Comparative study of diagnostic yield was done by Lee et al.,10 Jarmakani et al.11 and Khosla R et al.13 (Table 7)

A skilled radiologist and cytopathologist is the best combination as it provides a combined consultation between the pathologist and the radiologist and acquiring better cellular yield.1, 9, 17 This is beneficial for the patient and also a very rewarding and intellectually stimulating activity for the cytopathologist.19 The outcome of combined efforts also depends on patient co-operation, sub-optimal acoustic shadow and skill developed for aspirations.

Puncture of the cystic ovarian tumours could be hazardous, due to leakage and a potential tumour-cell implantation in the case of malignant tumours. Kjellgren has suggested trans-vaginal or a trans-rectal aspiration approach to avoid the risk of such implantation.17 In the present study, though the approach was trans-abdominal in all the cases except one, no such complications were encountered. The common complications like mild pain and discomfort were seen. The vast amount of literature supports the safety of FNAC.15 No report on complications like tumour seeding of the needle tract as a result of FNAC in the 20 papers were reported on around 20,000 patients, including those of the present study. 5 No such complication of haemorrhage or needle track seeding was seen in study done by Kouli R.20

The localization is good in most of the masses but, it is really challenging in few locations. (Table 8)

Few challenging conditions faced during the study where aspirations were not satisfactory. These cases were correlated with either biopsy or serum tumour markers or radiological images. Reasons for non-targeting the lesions were as follows-

The first work-up to be done after radiological report of large masses is to exclude benign from malignant lesions. FNAC aids in the delineation of benign from malignant in most of the cases. In the present study of radiologically diagnosed cases of masses, where real time guided FNAC had excluded malignancy were as follows:

As the present study is done at tertiary cancer centre, these patients were referred from outside facility with a suspicion of malignancy. Ultrasound guided FNAC aided in an early diagnosis of these suspicious lesions as benign or infective.

The age of patients in the present study was 18-76 years. In the study by Parajuli S et al 21 and Tan KB et al 22 age of patients were between 19- 83 years and 11-82 years respectively.

Out of 161 cases, guided FNAC were conclusive in 90.03% cases, inconclusive in 6.24% cases and acellular in 3.73%. The study done by Sheikh M 14Reyaz TA 15, Tuladhar AS, 8 Vasilj A 12 and Namshiker AAN 6 also gave conclusive diagnosis in 93.4%, 90.5%, 86.6%, 82.3% and 72.0%respectively. (Table 9)

Ultrasound guided FNAC has high sensitivity and specificity with high diagnostic yield and low complication rate. The sensitivity and specificity in the present study were 90.9% and 100% respectively. The study done by Satarkar R, 16 Momota N,3 Reddy S,5 Hemalatha AL,17 Mangal N, 2 Stewart CJR, 18 and showed sensitivity as 97.1%, 95.0%, 94.1%, 94.1%, 94.0% and 86% respectively. (Table 10 )

Guided FNAC of intra-abdominal organs like liver, kidney, lymph nodes and other pelvic masses are well appreciated, with no adverse impact on prognosis. The point of controversy exists for ovary FNAC, especially cystic ovarian masses.7 Historically FNAC from ovarian masses were discouraged due to expected risk of spillage and possible upstaging.23, 24 On the other hand preoperartive pathological diagnosis is very important to plan neoadjuvant chemotherapy.25 It can be done either by FNAC or trucut biopsy of ovary. In these cases risk ofseedling or spillage into peritoneal cavity can be prevented by using thin bore needle and avoiding multiple passes.26

To ascertain the complication rate associated with ultrasound guided puncture of gynecologic lesions, Zanetta et al27 did study of 838 cases of ovarian masses. No life-threatening complications were recorded. This study concluded that complication rates depend on the type of lesion. It is low in cases of serous cysts, solid tumors, and mixed tumors of ovary.

1. The study done by Dordoni et al. show no complications, except one case of persistent hematuria.28

However, puncture induced seedling of malignant cells by FNAC of ovarian masses is not supported by adequate and conclusive literature,29, 30 although the problem appears real.31 Larger trials should be targeted to address the issue of seedling/ spillage of malig­nant cells during the procedure are needed to prove or disprove its debatable role in diagnosis. The proce­dure, on the other hand, may help in avoiding unnecessary surgery or laparotomy and making decisions. In the present study out of 03 cases of tubo-ovarian masses 01 case was treated medically. Similarly the study done by Zanetta et al. also concludes that FNAC can decrease the need for surgery in many cases.27 Preventing surgeries can also aid in preserving the reproductive ability in young females.29, 32 Specific clinical scenarios where ovarian FNAC may represent the preferred approach are:23

Despite many controversial views regarding its safety, aspiration cytology of ovarian masses has been accepted as an innocuous procedure and it can be accomplished with minimal discomfort or complications.33 Minor complications such as pain or discomfort can be alleviated by analgesics.

In the present study any major complication or tumour seedling/ spillage were not seen in any case, of ovarian FNACs. Studies done by Hemalatha A L et al.,17 Kouli R,20 Virkar M et al29 and Pranab Dey et al.30 also did not reveal any case of tumour seedling.

Conclusion

Imaging can precisely localize the masses located intra-abdominally. But, imaging cannot delineate neoplastic from non-neoplastic lesions. Pathologists are well trained in performing and reporting FNACs of palpable masses. Challenge is to get good cellular yield from non-palpable masses where ultrasound guidance is required. Good hand eye co-ordination with ultrasound probe may help to reach the target areas. Synergistic approach of ultrasound and FNAC plays a very crucial role in diagnosing and delineating non-neoplastic from neoplastic lesions, without radiation, minimal pain and minimal cost. Early detection with appropriate therapy can be initiated rapidly, thus guiding clinicians in staging and planning the treatment of intra-abdominal masses.

Source of Funding

None.

Conflict of Interest

The authors declare no conflict of interest.