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Intra-abdominal masses always remain an enigma in surgical practice. A documentary evidence of nature of pathology before institution of therapy is mandatory and for prognosis. FNAC is a substitute for surgical procedures like diagnostic laparotomy.
Aims: To assess utility of FNA in the diagnosis of intra-abdominal lesions.
Objectives: To study the cytomorphological features, age and sex distribution of intra-abdominal lesions and categorize them organwise and as inflammatory, benign and malignant lesions. To classify malignant lesions according to cell type . To evaluate the sensitivity, specificity and diagnostic accuracy .
Meterials and methods: The study included 245 intra-abdominal lesions detected clinically or radiologically. Lesions were divided clinically into palpable and non-palpable lumps. USG or CT used for all non-palpable lesions and few palpable lesions and direct in selected palpable lesions. Giemsa and papanicolaou's stains were used.
Results: Mean age was 45.16 years with M:F of 1:1.3. Diagnostic yield was 92.1% in USG guided, 100% in CT guided and 95% in direct aspiration. There were 148 (60.3%) malignant, 55 (22.4%) benign, 25 (10.2%) inflammatory , one (0.6%) suspicious lesions and 16 (6.5%) unsatisfactory smears. Liver and ovary were most common sites . Adenocarcinomas and Hepatocellular carcinomas were most common malignant lesions. Study showed 94.1% sensitivity, 100% specificity, 100% positive predictive value, 92.3% negative predictive value and 96.5% diagnostic accuracy .
Conclusion: Intra-abdominal FNA is simple, economical, safe procedure with high sensitivity, specificity and diagnostic accuracy and can be utilized as pre-operative procedure in the management of intra-abdominal lesions.
Keywords: Intra-abdominal, FNA.
Intra-abdominal masses always remain an enigma in surgical practice. A documentary evidence of nature of pathology before institution of therapy is mandatory and also for prognosis. In majority of cases diagnosis obtained by FNAC is the substitute for surgical procedures like diagnostic laparotomy 1,2 Most intra abdominal masses are non - palpable and even if palpable the idea of size, shape and extent of lesion is not possible. Therefore various imaging modalities like fluoroscopy, CT, USG are used as a guide for fine needle aspiration.2 Most studies have shown it as highly sensitive, highly specific, accurate, cost effective diagnostic procedure with negligible complication rate.2-16 Uncorrectable severe coagulopathy is an absolute contraindication.17 FNA cytology was shown to be 100% specific for malignant diagnosis.4,8 The non -availability of CT, coupled with the higher incidence of advanced malignancy due to public awareness, overburdened surgical units with meagre resources requires USG - guided FNAC procedure for cancer management in developing countries like India.6,18 The aim of our study was to asses its usefulness as a pre-operative diagnostic procedure in the management of intra-abdominal lesions . Our objectives were to asses the cytomorphological features ,age and sex distribution and to classify malignant lesions according to cell type and evaluate sensitivity, specificity and diagnostic accuracy in different lesions wherever possible.
MATERIALS AND METHODS
Study was carried out in the Department of Pathology for a period of three years (36 months) from June - 2005 to May 2008. Patients with intra-abdominal lesions detected clinically or under radiological guidance presenting to Department of Cytology.
Intra-abdominal organs including liver, spleen, pancreas, stomach, gallbladder, small and large intestine, omentum, mesentery, retroperitoneum, kidney, adrenals, lymphnodes, soft tissues, ovary were included in the study. Parietal swellings arising from skin and abdominal wall, uterus, cervix, prostate and bone were excluded from the study.
After thorough clinical examination consent was obtained from the patient after explaining the procedure. Cases were divided clinically into palpable and nonpalpable lumps. Selected palpable lesions were subjected for direct aspiration and USG guidance in nonpalpable and deep seated lesion and few selected palpable lesions. The puncture site was marked. With aseptic precautions 22-23G needle for superficial lumps and lumbar puncture needle of same thickness for deep seated lumps fitted with 10ml syringe was introduced immediately under radiological guidance and aspiration was done under negative pressure. On an average two to three needle passes were made in each case to obtain adequate material. Sample was expelled on slides, air-dried and stained with Giemsa or fixed in 95% ethanol and stained with Papanicolaou's stain. Special stains were used wherever required.
The cases were analyzed based on cytological features. Final diagnosis was arrived on corroboration with clinical and radiological features. The smears were classified as inflammatory, benign, malignant, suspicious of malignancy and unsatisfactory for interpretation.
During study period 2624 fine needle aspirations were performed of which 234 cases were intra abdominal, accounting for 8.9% of the total cases. There were 245 lesions in 234 patients. There were 147 palpable and 98 non-palpable lesions. Histopathological correlation and confirmation was available in 29 cases.
Out of 234 cases there were 101 males and 133 females with a male to female ratio 1:1.3. The youngest patient in the study was 20 days old and the oldest 88 years. Majority of patients i.e., 146 (59.6%) were in the age group of 30-60 years out of 245 lesions. Mean age was 45.16 years (Standard deviation - 18.48). Among 104 lesions in male patients majority were malignant accounting for 76 (73.1%) and 12 (11.5%) lesions were inflammatory lesions, eight (7.7%) lesions were benign and one (0.9%) was suspicious for malignancy. In seven(6.8%) cases smears were unsatisfactory for evaluation. Among the 141 lesions in female patients 72 (51.1%) were malignant, 47 (33.3%) were benign and 13 (9.2%) were inflammatory. In nine (6.4%) cases smears were unsatisfactory for evaluation. Out of 245 lesions in 234 patients 148 (60.3%) were malignant, 55 (22.4%) were benign, 25 (10.2%) were inflammatory and one (0.6%) was suspicious lesion. There were about 16 (6.5%) unsatisfactory smears. Benign lesions were more common in females than in males, where as malignant lesions had slight male preponderance. The incidence of lesions in both increased after 30 years [Table. 1,3].
Out of 245 lesions, 164 were aspirated under ultrasonographic guidance and one was aspirated under computed tomographic guidance. In 80 cases which were properly selected palpable cases were aspirated directly without any guidance technique. The diagnostic yield of USG was 92.7% i.e., out of 163 USG guided procedures, adequate material was obtained in 152 cases. In CT guidance procedure the diagnostic yield was 100%. It was 95% in direct unguided procedure which is higher than that of USG guided procedure. Overall diagnostic yield was 93.5% in 245 lesions. [Table. 2].
In the present study, most of the aspirates were cellular (41.6%) and hemorrhagic cellular (28.6%). It was fluid aspirate in 11.8% lesions followed by necrotic in 6.5% lesions, purulent in 2.9% lesions and acellular hemorrhagic in 8.6% lesions. Out of 21 hemorrhagic and acellular hemorrhagic aspirates most were (16 cases) unsatisfactory for evaluation and five were interpreted as hemangiomas. Out of 245 lesions aspirate was satisfactory in 229 (93.5%) lesions. Unsatisfactory aspirate was obtained 16 (6.5%) lesions. [Table. 3].
Majority of lesions were located in liver and malignant lesions constituting most of them. Most common malignant lesion in liver was hepatocellular carcinoma (34) [Figure-1a,b] followed by metastatic carcinoma (25). In seven cases we could not differentiate between primary HCC and metastatic lesions and were labeled as poorly differentiated carcinoma. One case was diagnosed as cholangiocarcinoma [Figure-2] in a 50 years old female. Next most common site was ovary (48) where most were benign lesions (33). Other common organs involved were lymphnodes (18), kidney (12), gallbladder (6) and pancreas (6).There were two cystic lesions of pancreas and four adenocarcinomas of pancreas. In gall bladder all were adenocarcinomas.
Abscess constituted most common inflammatory lesion. Out of eight abscess six were located in liver, one in lymphnode and one in appendix. There were five tubercular lymphadenitis [Figure-3] and three reactive lymphadenitis cases. Four cases of diffuse parenchymal lesion of liver were seen.
Most of the benign lesions i.e., 33 lesions were located in ovary and most of them (11) were diagnosed as cystadenoma,. Among remaining benign lesions nine (16.5%) lesions were diagnosed as cyst contents, six (10.9%) as serous cystadenoma, three (5.4%) as mucinous cystadenoma, one as simple serous cyst, one as twisted ovarian cyst, three (5.4%) as benign teratoma, one ovarian fibroma and one as benign mixed epithelial stromal tumor [Figure-4]. Two cystic lesions were in pancreas and one in liver (calcified cyst content). There were five hemangiomas all located in liver out of 55 cases i.e. 9.1% of benign lesions. There was one angiomyolipoma, one adrenal cortical adenoma, one benign trophoblastic lesion and one mucinous cyst of mesentery and colon each.
Adenocarcinomas [Figure-6] were most common malignant lesions followed by hepatocellular carcinomas. Adenocarcinomas were more common in females (23) than in males (16). Hepatocellular carcinomas were more common in males (25) than in females (nine). Lymphoma [Figure-7], renal cell carcinoma [Figure-8], nephroblastoma [Figure-9] and small cell carcinomas were more common in males than in females. Pleomorphic sarcomas were more common in females (three) than in males (one). Serous cystadenocarcinoma (seven) was most common malignant lesion in ovary fallowed by one malignant granulosa cell tumor [Figure-10] , one dysgerminoma[Figure-11] and remaining were metastatic adenocarcinomas. Majority of adenocarcinomas (25) and Hepatocellular carcinomas (20) were seen in the age group of 41-60 years. Youngest patient affected by HCC was 18 years female and oldest was 85 years male. Adenocarcinoma constituted most common metastatic lesion to the liver followed by small cell carcinoma (three). All nephroblastomas and one malignant small round cell tumor and one rhabdomyosarcoma were seen below 20 years of age. One rhabdomyosarcoma was seen in 40 years old male [Table. 5].
Out of 32 hepatocellular carcinomas HbsAg test was done in nine cases of whom six were positive and three were negative. 66.7% of HbsAg positivity was seen in hepatocellular carcinoma.
Histopathological correlation and confirmation was available in 29 cases. Out of 13 benign cases seven were confirmed on histopathologic examination. All mucinous and serous cystadenomas diagnosed cytologically were confirmed on histopathologically, except one mucinous cystadenoma which was diagnosed as papillary cystadenofibroma and one serous cystadenoma turned out to be serous cystadenocarcinoma on histopathologic examination.Benign mixed epithelial stromal tumor turned out to be Brenner tumor of ovary on histopathological examination. One twisted ovarian cyst and one ovarian fibroma were confirmed histologically. One cystadenoma with hemorrhage and one spindle cell tumor turned out to be twisted ovarian cyst and leiomyoma of retroperitoneum respectively.
11 cases were confirmed histologically out of 16 malignant cases. All serous cystadenocarcinomas of ovary, one malignant granulosa cell tumor, one clear cell carcinoma of kidney, two nephroblastomas, one gallbladder adenocarcinoma, one large intestine adenocarcinoma and two adenocarcinomas of ovary, one ganglioneuroblastoma [Figure-12] were confirmed histologically One case of clear cell carcinoma of the kidney turned out to be adrenocortical carcinoma on histopathological examination. One case of malignant undifferentiated tumor turned out to be malignant mixed epithelial cell tumor with dysgerminoma and embryonal carcinoma, one case of carcinoma with tuberculosis turned out to be metastatic adenocarcinoma of the ovary on histopathologic examination. One case who presented with suprapubic abdominal mass was diagnosed as adenocarcinoma cytologically. But histologic diagnosis of cervical biopsy was squamous cell carcinoma. In one case of metastatic seminoma to lymphnode diagnosed cytologically showed teratocarcinoma on histopathological examination of orchidectomy specimen.
FNAC is a proven technique for diagnostic evaluation of intra-abdominal lesions. The diagnostic yield obtained by USG was 92.7% and CT was 100% and for direct aspiration it was 95%. Overall diagnostic yield was 93.5%. Nautiyal S., Mishra RK., and Sharma SP,2 in 2004 found diagnostic yield of 64.81% for direct aspiration in palpable lumps and 93.06% in USG guided FNAC done in both palpable and non-palpable lesions. Nyman et al,12 in 1995 found diagnostic yield of 64% in USG guided FNAC. In comparison with the previous studies present study had more diagnostic yield wether it is direct or guided. In the present study the diagnostic yield was more with direct aspiration than with USG guided. This could be due to careful and proper selection of cases for direct aspiration and in most lesions were superficial and easily palpable .100% diagnostic yield obtained with CT-guided FNAC was comparable with that of Joseph T. et al.8
Age incidence in the present study ranged from 20 days to 88 years with majority in 30-60 years (59.6%). The incidence of malignancy increased after the age of 40 years in males and after 30 years in females. With peak incidence between 40-60 years, comparable with Zawar MP., et al,3and Shamshad et al.14
Male to female ratio of 1:1.3 was in accordance with the observations made by Shamshad et al,14 and Joao Nobrega et al.4 But observations made in the studies by Zawar MP et al3 Govind Krishna et al10 Aftab A Khan et al,1 and Ennis and Mac Erlean,6 showed male preponderance. This could be due to inclusion of ovary in this study as done by Shamshad et al.14
The most common organ involved in the present study was liver an observation similar to one made by Zawar M.P. et al,3and Biradar et al.11 Next most common site in the present study was ovary. But ovary was not included in the study made by Zawar M.P. et al,3 and Biradar et al.11 In their study next most common site was large intestine. Biradar et al,14 had included Gallbladder, Spleen, Adrenal, Soft tissue, Omentum and mesentery in unclassified category [Table. 5].
In the present study malignant lesions constituted most common diagnostic category which is in accordance with the observations made by Biradar et al,11 Aftab A. Khan et al,1 and Shamshad et al.14 [Table.6].
In the present study we observed 6.5% of unsatisfactory smears similar to observations made by Shamshad et al,14 and Aftab A. Khan et al,1 who observed 6.5% and 6% unsatisfactory smears. Biradar et al,11 had observed more unsatisfactory smears (14%) compared to our study. [Table. 6].
Benign lesions showed high female preponderance in the present study because cystic lesions of ovary were most commonly seen benign lesions. There was no age or sex predilection for inflammatory lesions in the present study.
In the present study adenocarcinomas were most common malignant cell type (26.3%) followed by hepatocellular carcinoma (23%), renal cell carcinoma (4.7%), serous cystadenocarcinoma (4.7%) and nephroblastoma (2.7%) and poorly differentiated carcinomas constituted 19.6% of lesions in the present study. This was in accordance with the observations made by Shamshad et al,14 and Aftab A. Khan et al,1 who observed 87.1% and 34% respectively. Second most common malignant type in there studies was also hepatocellular carcinoma. In liver the most common malignant lesion was hepatocellular carcinoma (34) followed by metastatic carcinomas (25). In western literature most common hepatic malignancy was metastasic carcinoma. 4,6,18.19,20 This could be because of high prevalence of Hepatitis B infection and consumption of chutney made up of groundnuts frequently contaminated with aflatoxins in this geographical region. Present study observations are similar to Indian studies where hepatocellular carcinoma constituted most common hepatic malignancy.3, Two studies conducted in Kashmir showed observation similar to western literature.1,14
Liver constituted major site for malignant lesions as observed by Aftab A. Khan et al,1 Stewart et al,5 Zawar MP et al,3 Nyman et al, 12 Ennis and MacErlean,6 Joao Nobrega et a,4 Nautiyal et al.2. But in observation made by Shamshad et al,14 and Joseph et al,8 the most common organ site for malignant lesions was Gallbladder and pancreas respectively. Hepatocellular carcinoma was most commonly seen in males in accordance with the previous literature.3,20 Hepatocellular carcinomas and adenocarcinomas, had peak incidence in the age group between 40-60 years in accordance with the observations made by Shamshad et al,14 Zawar MP et al.3 Malignant tumors which were seen before 20 years of age were, nephroblastoma and other round cell tumors, Hodgkin's lymphoma, dysgerminoma, Ganglioneuroblastoma. This observation was comparable to the previous literature.18,20
Although few studies have reported complications like mild local pain, bleeding and tumor seeding of needle tract, vast amount of literature supports the safety of FNAC. There was no report of complication in 20 papers amounting to around 20,000 patients including the present study.
Sensitivity of USG guided FNAC ranged from 71.4% to 96.3%. In the present study it was 94.1% which was comparable to most of the studies. All studies observed 100% specificity, the same observation what we have made in the present study. Diagnostic accuracy in various studies ranged from 83.9% to 100%. Present study found diagnostic accuracy of 96.5% which is comparable to most of the studies. [Table. 7].
Intra-abdominal FNA is a relatively simple, economical, quick and safe procedure in the diagnosis of intra-abdominal lesions. It not only helps in differentiating between, inflammatory, benign and malignant lesions but also in categorizing different malignant lesions. Intra-abdominal FNA is a reliable, sensitive and specific method with high diagnostic accuracy in the diagnosis of malignant lesions. It can be utilized as pre-operative procedure in the management of all intra-abdominal lesions.