|Year : 2016 | Volume
| Issue : 2 | Page : 159-161
FNAC a diagnostic modality in cysticercosis: Study of 148 cases with a brief review
Pooja Srivastava, Sachin Kolte, Kusum Gupta
Department of Pathology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
|Date of Web Publication||5-Jul-2016|
270, Hauz Rani Malviya Nagar, New Delhi - 110 017
Aim: This study was done to analyze clinicopathological and fine-needle aspiration (FNA) findings of cysticercosis in a tertiary care center. Settings and Design: Retrospective data collected from April 2013 to December 2014 were analyzed. Materials and Methods: One hundred and forty-eight cases of suspected parasitic infection, who presented with soft tissue swelling, were analyzed. Results: Out of 148 cases 100 cases showed presence of parasitic fragments on FNA cytology (FNAC), while the rest 48 cases were reported as suggestive of parasitic infection. Conclusion: FNAC in cysticercosis is a low-cost, minimally invasive outpatient procedure. The cytological diagnosis is clear-cut in cases where the parasite structure is identified in the smears. In other cases, features suggestive of parasitic infection can help in indicating the possibility of the disease.
Keywords: Cysticercus, fine-needle aspiration cytology, parasite
|How to cite this article:|
Srivastava P, Kolte S, Gupta K. FNAC a diagnostic modality in cysticercosis: Study of 148 cases with a brief review. Trop J Med Res 2016;19:159-61
| Introduction|| |
Fine-needle aspiration cytology (FNAC) is an outpatient minimally invasive procedure. Its use was first suggested by Saran et al.  in the diagnosis of parasitic diseases. Cysticercosis is caused by larval stage of pork tapeworm Taenia solium, and it is endemic in India, China, sub-Saharan Africa, and Central and South America.  The sites having predilection for development of cysticerci are the central nervous system, subcutaneous tissue, skeletal muscle, cardiac muscle, and the eye.  There are various diagnostic modalities that are currently in use, such as radiological imaging [computed tomography (CT) scan and magnetic resonance imaging (MRI)] and serological tests such as complement fixation test, hemagglutination, radioimmunoassay, and enzyme-linked immunosorbent assay (ELISA), for preoperative diagnosis of cysticercosis, but demonstration of parasitic larva by cytology or histopathology is still the gold standard.  FNAC, thus, forms an easy, cheap, and minimally invasive approach for the definitive diagnosis of the disease.
This study was done to analyze the clinicopathological and fine-needle aspiration (FNA) findings of cysticercosis.
| Materials and Methods|| |
The study was performed in a tertiary care referral hospital with a workload of around 13,000 FNAC annually. Retrospective data collected from April 2013 to December 2014 in which 148 cases suspected of parasitic infection were analyzed. FNAC was performed with a 22-gauge needle. Smears were prepared from the aspirated material and stained with Giemsa stain. Wherever the amount of aspirated material was more, cytocentrifuge smears were prepared. Ziehl-Neelson (ZN) stain was done to rule out the possibility of tuberculosis wherever required.
| Results|| |
Out of the 148 cases, 100 cases showed parasitic fragments such as bladder wall comprising of outer acellular pinkish layer, followed by subcuticular or tegumental cells with small pyknotic-looking nuclei in a loose, fibrillary parenchyma [Figure 1] and [Figure 2] and were diagnosed as cysticercus cellulosae on FNAC. These were the cases that were included in the study. The patients were in the age group range of 1-58 years [Table 1]. Incidence of the disease was almost equal in males (55%) and females (45%) [Table 2]. Peak age of incidence was reported in the second decade (34%) followed by the first decade (27%), and only a few cases were reported in older patients. There was one case reported in a 1-year-old child. Most commonly affected sites were abdomen (20%) and upper extremity (20%), followed by cervical region (19%) [Table 3]. Among the unusual sites one case was reported on tongue and other in breast. Clinical diagnosis was tuberculous lymphadenitis in 30 cases, lipoma in 37 cases, and neuroma in 13 cases. Other provisional clinical diagnoses were fibroma, sialadenitis, secondaries, etc., The smears from remaining 48 cases were extensively searched for evidence of parasite, but no definite parasitic fragment was seen. However, in view of the clear fluid aspirated and presence of acute suppurative inflammation comprising of eosinophils, neutrophils and histiocytes, and occasional presence of calcareous corpuscles, they were reported as suggestive of parasitic infection [Figure 3].
|Figure 1: Photomicrograph showing the fragment of parasite (Giemsa ×100)|
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|Figure 2: Photomicrograph showing bladder wall fragment set in a loose, fibrillary parenchyma (Giemsa ×400)|
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|Figure 3: Photomicrograph showing acute inflammatory cell population comprising of eosinophils, neutrophils, and histiocytes (Giemsa ×100)|
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| Discussion|| |
Cysticercosis is caused by larval stage of T. solium that is cysticercus cellulosae. Humans are the definitive host and pig is the intermediate host. Infection occurs by consumption of the eggs of worm from undercooked meat or contaminated vegetables. These eggs disseminate to various tissues of the host through the hematogenous route, so it has a high propensity for localization in the organs that have an ample blood supply like the brain, muscles, and subcutaneous tissues.  Inflammatory response leads either to degeneration of the larva or granuloma formation and calcification.
The presenting complaint in most of the cases was of slowly growing painless nodule in the subcutaneous tissue for few weeks to months. The size of the nodule ranged from 0.5 to 3 cm in diameter. Clinical diagnosis was varying based on the site of the lesion. The most common sites were abdomen and upper limb where the differential diagnosis included infectious swelling and soft tissue tumor, while when the swelling was in cervical region most common differential diagnosis was tuberculosis. Amongst the uncommon sites, one case was reported on tongue and the other in breast. In majority of cases, the aspirated material was thin and clear but in some it was purulent. Other studies have also stated that aspiration of clear fluid is a strong indicator toward parasitic infestation, although in a significant number of cases, aspirate may also be purulent or hemorrhagic. , ZN stain was performed on all these cases where the aspirated material was pus like and also when swelling was present in cervical region to rule out the possibility of tuberculosis.
An interesting feature that was seen in our study was that if first aspirate yielded a clear fluid and parasite fragments/hooklets were not seen in the smears, a repeat aspirate done on same day or within few days increases the chances of yield of parasite fragments.
Out of the 148 cases, 100 cases showed presence of parasite fragment either on first or repeat aspiration. The other 48 cases were reported as suggestive of parasitic infection because of the aspiration of clear fluid, presence of inflammatory cells comprising of eosinophils, neutrophils, histiocytes and giant cells against a necrotic background. Also ZN stain was performed on these smears and was found to be negative for acid-fast bacilli, thus ruling out the possibility of tuberculosis. The cytomorphological identification of larvae in FNAC smears by different authors has not only improved the diagnostic utility of FNAC in skin nodules but also has reduced the chances of diagnostic and therapeutic error. ,,, In all inflammatory/cystic lesions, particularly in endemic areas, the possibility of cysticercosis should be taken into consideration irrespective of age, location, and the size of the lesion. , Thus, FNAC forms an easy diagnostic approach in case of parasitic infections, as cytological diagnosis is quite straightforward in cases where the actual parasite structure is identified in the smears. In other cases, presence of acute suppurative inflammation along with aspiration of clear white fluid and occasional presence of calcareous corpuscles help in indicating a possibility of parasitic infection. In a country like India where both parasitic infections and tuberculosis are common it helps in definitive diagnosis and thus prevents undue delay in the treatment.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]