Journal of Cytology
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ORIGINAL ARTICLE Table of Contents   
Year : 2008  |  Volume : 25  |  Issue : 4  |  Page : 123-127
Radiologically guided fine needle aspiration cytology of retroperitoneal and spinal lesions

1 Department of Pathology, J.N. Medical College, AMU, Aligarh - 202 002, India
2 Department of Radiodiagnosis, J.N. Medical College, AMU, Aligarh - 202 002, India
3 Department of Surgery, J.N. Medical College, AMU, Aligarh - 202 002, India

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Aim: This study was undertaken to assess the role of image-guided, fine needle aspiration cytology (FNAC) in the diagnosis of retroperitoneal and spinal lesions.
Materials and Methods: Over a period of one year, ultrasonography and computerized tomography-guided FNAC was performed in 55 cases who had presented clinically with signs and symptoms related to the retroperitoneum and spine. Histopathological confirmation was available in 27 out of 55 cases.
Results: Of the 55 cases, 39 were males and 16 were females. Malignant and benign lesions accounted for 58.2 and 29.1% respectively. Among the cases on whom radiologically guided FNAC was performed, the spine contributed the largest proportion of cases (32.7%), followed by renal lesions (20%). Among the malignant lesions, renal cell carcinoma was the most commonly found malignancy, followed by metastasis to the spine. In the benign and inflammatory category, tuberculosis of the spine and the lymph nodes was the most common lesion accounting for 68.7% of all cases. On correlating clinical, radiological, and cytologic features, the sensitivity, specificity, and overall accuracy of guided FNAC obtained in this study were 97.1, 84.2, and 92.4% respectively.
Conclusions: Radiologically guided FNAC is a fairly accurate and safe procedure in diagnosing the most difficult cases in the region of the retroperitoneum and the spine.

Keywords: FNAC; radiologic-guidance; retroperitoneum; spine.

How to cite this article:
Aziz M, Afroz N, Kahkashan E, Ahmad I, Mansoor T. Radiologically guided fine needle aspiration cytology of retroperitoneal and spinal lesions. J Cytol 2008;25:123-7

How to cite this URL:
Aziz M, Afroz N, Kahkashan E, Ahmad I, Mansoor T. Radiologically guided fine needle aspiration cytology of retroperitoneal and spinal lesions. J Cytol [serial online] 2008 [cited 2023 Mar 27];25:123-7. Available from:

   Introduction Top

The retroperitoneum and the spine have long been areas of curiosity and interest with regard to the diagnosis of lesions occurring in these regions, more so because the usual diagnostic armamentarium falls short of providing the requisite access. Considering the numerous and heterogenous contents of these regions, lesions that can be potentially encountered here are numerous. These may either be organ-specific or may occur in lymph nodes, soft tissue, bone, or the neural element. Fine needle aspiration cytology (FNAC) has become a common and important mode of evaluating vertebral and paravertebral lesions. [1] In the majority of cases, there is a known history of malignancy, and FNAC is performed either to confirm or exclude the presence of metastasis. [2],[3] In patients without a known primary tumor, a positive cytology may be the first indication of malignancy and thus, may aid in the search for an occult primary. Obtaining cytological material in infectious/ inflammatory lesions allows rapid identification of organisms and initiation of treatment in many cases.

   Materials and Methods Top

Fifty-five cases of ultrasonography (USG)- and computerized tomography (CT)-guided FNAC performed during a period of one year (2002-2003) at our Institute were analysed, to assess the role of image-guided FNAC in the diagnosis of retroperitoneal and spinal lesions. The cytological material obtained in all 55 cases were stained by May-Grünwald-Giemsa (MGG) (air-dried smears), by conventional Papanicolaou (Pap), and hematoxylin-eosin (H and E) methods (alcohol-fixed smears).

FNAC was performed in patients who presented clinically with signs and symptoms related to the retroperitoneum and spine and in radiologically suspicious lesions to confirm or exclude a possible malignant lesion. Smears were evaluated as four diagnostic categories: (1) malignant, (2) suspicious for malignancy, (3) benign and inflammatory, and (4) unsatisfactory.

Histopathological confirmation was available in 27/55 cases. These included diagnosed cases of cancer as well as new cases that underwent surgical excision after FNAC evaluation. Relevant special stains (reticulin and periodic acid Schiff stain) were performed wherever indicated.

   Results Top

Of the 55 cases, 39 were males and 16 were females. There were 16 (29.1%) cases of benign and inflammatory lesions, whereas malignancy accounted for a total of 32 (58.2%) cases. Three cases were reported as being 'suspicious for malignancy' while four smears were 'unsatisfactory' due to scant cellularity, poor cellular preservation, obscured cellular details, or pronounced contamination with blood.

[Table 1] shows the distribution of cases according to the site of the lesion diagnosed on radiology-guided FNAC. The majority of aspirates were obtained from spinal and renal lesions, which accounted for 32.7 and 20% cases, respectively.

The spectrum of 16 'benign and inflammatory lesions' included eight cases of tuberculosis of the spine (Pott's spine) [Figure 1a] and [Figure 1b], three cases of retroperitoneal, tuberculous lymphadenitis, two cases of retroperitoneal, nonorgan-specific, cystic, inflammatory lesion, and one case each of benign nerve sheath tumor of the spinal nerve, acute pyelonephritis, and pheochromocytoma. The latter was considered in the benign category as it is rarely malignant and even when malignant, the prognosis is much better than that of adrenal cortical carcinoma.

Out of the 32 'malignant tumors', the majority were from renal lesions, with renal cell carcinoma (RCC: seven cases) being the most commonly observed tumors, followed by spinal metastases (six cases), and finally, round cell undifferentiated tumors of the retroperitoneum (four cases) [Table 2].

Results of histopathological examination were available in only two out of the four round cell tumors, which included a case of neuroblastoma and another of extraskeletal Ewing's sarcoma. The remaining two cases were lost to follow-up.

Out of 55 cases studied, a total of 53 lesions were diagnosed and two cases with unsatisfactory aspirates were lost to follow-up. Thirty-four were malignant cases (33 true positive and one false negative), whereas 19 were nonmalignant, i.e ., 16 true negative and three false positive [Table 3]. The three false positives included two cases of perinepheric inflammatory lesions containing numerous histiocytes that had been misinterpreted as being cells of renal cell carcinoma, and one case of chronic pancreatitis with epithelial atypia simulating pancreatic carcinoma.

The sensitivity and specificity of radiologically guided FNAC in the diagnosis of retroperitoneal and spinal neoplasms were 97.1 and 84.2% respectively, with a positive predictive value of 91.7%, negative predictive value of 94.1%, and an overall accuracy of 92.4%.

   Discussion Top

USG-guided FNAC is now a common practice due to its cost-effectiveness, ease of performance, accuracy, repeatability, the lack of exposure to radiation, and rapidity in diagnosis. CT guidance provides accuracy and reliability and makes sampling of very small lesions easy. Further, it also enables imaging of very low-density material such as 'gas in the bowel'. Critical areas which may be lost to visualization with a change of position during USG, are best suited for CT-guided FNAC. [3] We report our experience with USG- and CT-guided FNAC of lesions of the spine and retroperitoneum. Both the procedures showed good patient compliance and were repeatable. Thus, cytodiagnosis of lesions was made as accurate as possible.

Of all retroperitoneal lesions, the spine contributed the largest proportion of cases (32.7%) followed by the kidney (20%). In the region of the retroperitoneum, most of the malignancies arose from the kidney. The nonorgan-specific, soft tissue tumors and retroperitoneal lymph nodes were the next most important contributors of lesions in this region.

'Benign and inflammatory lesions' were mainly attributable to the spine and lymph nodes, with tuberculosis being the most commonly encountered disease (68.7% of all benign and inflammatory lesions), which was similar to findings reported by Kishore et al . [4]

Among the malignant tumors noted in the present study, RCC which constituted 87.5% of malignant renal tumors, was the most commonly found entity, a finding that was similar to the observation of Mondal et al . [5] Of the six adrenal tumors, two were diagnosed as neuroblastoma and two as metastatic cancer; one was a case of pheochromocytoma and one of adrenal cortical carcinoma. Nguyen [6] had described the cytological and histological findings of pheochromocytoma and had suggested that it should be differentiated from hepatocellular carcinoma, RCC, and metastatic malignant melanoma in cytology samples. In the above study, metastatic lesions to the adrenal gland were found to originate from the breast in a female and from the lung in a male, findings that were also reported by Heilberg and Wolvorson. [7]

Two malignant cases from the retroperitoneal lymph nodes showed features of non-Hodgkin's lymphoma, and leukemic involvement of the lymph nodes. al-Mofleh [8] had found that five out of seven malignant cases were lymphomas, i.e ., about half of the malignancies, a result that was similar to that of the present study.

The observation of metastatic lesions in the spine in the present study was in agreement with the studies of Kishore et al. [4] and Mondal et al. [9]

The nonorgan-specific tumors of the retroperitoneum included four cases of round cell, undifferentiated malignancy and a case of immature teratoma. In a study of 96 such lesions, Juul et al. [10] had found malignancy in 75 cases while 21 were benign lesions. Retroperitoneal extension of bowel tumors was found in two cases. The tumors were bulky, filling the retroperitoneal space, although on further workup and CT-guided FNAC, the exact origin was established in one case to be from the gastrointestinal tract, whereas the other case was a subdiaphragmatic extension of a paraspinal, large cell, lung carcinoma. Such extensions have been also observed by Droese et al. [11]

The sensitivity of FNAC obtained in our study was 97.1%, compared to the sensitivity of 84.4, 85, and 100% reported by Droese et al., [11] al-Mofleh et al. [8] and Ahmad et al. [12] respectively. The specificity was 84.2% compared to 100% reported by Ahmad et al., [12] while the overall accuracy was 92.4% in our study, similar to 91% obtained by Memel et al. [13]

No complications were encountered during the study, although a few patients complained of pain at the puncture site which only lasted for a short duration.

   Conclusions Top

Radiologically guided FNAC is an accurate, safe, and repeatable procedure in the diagnosis of very difficult cases in the region of the retropertitoneum and spine, due to precise and continuous visualization of the lesion without any undue exposure to radiation. CT scan has enabled the visualization of previously inaccessible tumors, which can now be aspirated by this guided technique, leading to greater yield of cytological material and a significantly greater predictability of true positive cases in malignant lesions.[Figure 2a],[Figure 2b],[Figure 3a],[Figure 3b],[Figure 4a],[Figure 4b]

   References Top

1.Carson HJ, Castelli MJ, Reyes CV, Gattuso P. Fine-needle aspiration biopsy of vertebral body lesions: Cytologic, pathologic, and clinical correlations of 57 cases. Diagn Cytopathol 1994;11:348-51.  Back to cited text no. 1  [PUBMED]  
2.Agarwal PK, Goel M, Chandra T, Agarwal S. Predictive value of fine needle aspiration cytology of bone lesions. Acta Cytol 1997;41:659-65.  Back to cited text no. 2    
3.Mondal A, Kundu B, Ray CK, Saha DK, Biswas J, Misra DK. Utility of imaging modalities in diagnostic FNAC. J Cytol 2002;19:123-38.  Back to cited text no. 3    
4.Kishore LT, Gayatri K, Rao S, Prasad BN. Percutaneous biopsy of vertebrae-Preliminary report of 100 biopsies. Indian J Radiol Imaging 1992;2:133-8.  Back to cited text no. 4    
5.Mondal A, Ghosh E. Fine needle aspiration cytology (FNAC) in the diagnosis of solid renal masses: A study of 92 cases. Indian J Pathol Microbiol 1992;35:333-9.  Back to cited text no. 5    
6.Nguyen GK. Cytopathologic aspects of adrenal pheochromocytoma in fine needle aspiration biopsy: A case report. Acta Cytol 1982;26:354-8.  Back to cited text no. 6  [PUBMED]  
7.Heilberg E, Wolvorson MK. Ipsilateral decubitus position for percutaneous CT-guided adrenal biopsy. J Comput Asst Tomogr 1985;9:217-8.  Back to cited text no. 7 IA. Ultrasound-guided fine needle aspiration of retroperitoneal, abdominal and pelvic lymph nodes: Diagnostic reliability. Acta Cytol 1992;36:413-5.  Back to cited text no. 8  [PUBMED]  
9.Mondal A, Misra DK. CT-guided needle aspiration cytology (FNAC) of 112 vertebral lesions. Indian J Pathol Microbiol 1994;37:255-61.  Back to cited text no. 9    
10.Juul N, Trop-Pedersen S, Holm HH. Ultrasonically guided fine needle aspiration biopsy of retroperitoneal mass lesions. Br J Radiol 1984;57:43-6.  Back to cited text no. 10    
11.Droese M, Allmannsberger M, Kehl A, Lankisch PG, Weiss R, Weber K, et al . Ultrasound-guided percutaneous fine needle aspiration biopsy of abdominal and retroperitoneal masses: Accuracy of cytology in the diagnosis of malignancy, cytologic tumor typing and use of antibodies to intermediate filaments in selected cases. Acta Cytol 1984;28:368-84.  Back to cited text no. 11    
12.Ahmad SS, Akhtar K, Akhtar SS, Nasir A, Khalid M, Mansoor T. Ultrasound guided fine needle aspiration biopsy of retroperitoneal masses. J Cytol 2007;24:41-5.   Back to cited text no. 12    Medknow Journal
13.Memel DS, Dodd GD 3rd, Esola CC. Efficacy of sonography as a guidance technique for biopsy of abdominal, pelvic and retroperitoneal lymph nodes. AJR Am J Roentgenol 1996;167:957-62.  Back to cited text no. 13  [PUBMED]  [FULLTEXT]

Correspondence Address:
Nishat Afroz
C-44, Medical Colony, AMU, Aligarh - 202 002
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-9371.50796

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  [Figure 1a], [Figure 1b], [Figure 2a], [Figure 2b], [Figure 3a], [Figure 3b], [Figure 4a], [Figure 4b]

  [Table 1], [Table 2], [Table 3]

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