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Year : 2018  |  Volume : 3  |  Issue : 1  |  Page : 58-60

Microfilaria in fine-needle aspiration cytology of renal mass – an unusual site: A rare case report

1 Department of Pathology, Yashoda Hospital, Hyderabad, Telangana, India
2 Department of Radiology, Yashoda Hospital, Hyderabad, Telangana, India

Date of Submission29-Mar-2018
Date of Acceptance24-Apr-2018
Date of Web Publication19-Jun-2018

Correspondence Address:
Dr. Majed Momin
Department of Pathology, Yashoda Hospital, Malakpet, Nalgonda X-Roads, Hyderabad - 500 036, Telangana
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/bjhs.bjhs_7_18

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In tropical countries like India, filariasis is one among the major public health problems. Most commonly (90%) cases of lymphatic filariasis caused by wuchereria bancrofti, and rest (10%) cases by Brugia malayi. In India, filariasis is transmitted by the bite of culex or mansonia mosquito species. The diagnostic method of choice in filariasis is the detection of microfilaria in peripheral blood film examinations. Microfilaria was incidentally detected in fine-needle aspiration cytology (FNAC) smears from different tissues, organs, and serous cavities. However, the presence of a filarial worm in renal mass aspirate is unusual, and no literature has been published with best of our knowledge. We report a case in which ultrasound-guided FNAC renal mass revealed the presence of microfilaria in the background of renal cell carcinoma cells.

Keywords: Filariasis, renal cell carcinoma, ultrasonography guidance fine-needle aspiration cytology

How to cite this article:
Momin M, Ingle A, Sandeep S. Microfilaria in fine-needle aspiration cytology of renal mass – an unusual site: A rare case report. BLDE Univ J Health Sci 2018;3:58-60

How to cite this URL:
Momin M, Ingle A, Sandeep S. Microfilaria in fine-needle aspiration cytology of renal mass – an unusual site: A rare case report. BLDE Univ J Health Sci [serial online] 2018 [cited 2021 Apr 14];3:58-60. Available from: https://www.bldeujournalhs.in/text.asp?2018/3/1/58/234649

Filariasis is a parasitic disease related to severe morbidity and its incidence is more in tropical and subtropical areas. Filariasis is endemic in India and prevalent in both rural and urban regions. Out of three nematode parasites, wuchereria bancrofti and Brugia malayi are seen in India and both nematodes transmitted by a female mosquito.[1] As per review of literatures, microfilaria was incidentally detected in fine-needle aspiration cytology (FNAC) sample from organs such as thyroid, breast, subcutaneous nodules, bronchial washings, cervical scrapings, and body fluids.[2]

Ultrasound-guided FNAC renal mass was usually performed to know the biological nature of renal mass preoperatively. Renal cell carcinoma (RCC) FNAC cytosmears do not cause morphological difficulties, whether tumor is primary or secondary deposit.[3] Microfilaria in renal mass is a rare incidental finding, and not a single case report has been published in literature and its presence does not indicate any role in the pathogenesis of malignancies.

  Case Report Top

A 45-year-old female visited a surgeon with a history of right-sided abdominal pain for 6 months. On general examination, she had pallor, and systemic examination was normal except right lumbar region tenderness on palpation. Ultrasound examination shows mass in the retroperitoneal region arising from middle and lower poles of the right kidney measuring 54 mm × 46 mm in dimension [Figure 1] and [Figure 2]. There was no hemoparasite in peripheral thick and thin smear films, and eosinophil count was normal.
Figure 1: Ultrasonography right kidney: Well-defined hypoechoic mass lesion arising from the mid and lower pole cortex of the kidneys with internal vascularity

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Figure 2: Ultrasound-guided fine-needle aspiration cytology from the right kidney mass lesion showing the needle in the lower pole lesion (white-dotted arrow)

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Ultrasonography-guided FNAC was carried out to get renal mass aspirate and stained with hematoxylin and eosin and Papanicolaou. Microscopic examination shows tumor cells arranged in loose cohesive clusters and scattered individually. Tumor cells show anisonucleosis with low N: C ratio, round nuclei, and abundant pale, vacuolated cytoplasm. Many of the single cells are foamy macrophages. Cytology findings are consistent with RCC. In addition, few microfilariae are seen in the background with nuclei (somatic cells) seen as granules and extended from head to tail except its tip making diagnosis of wuchereria bancrofti [Figure 3]b, [Figure 3]c, [Figure 3]d. The patient was treated with diethylcarbamazine before surgical excision.
Figure 3: (a) Fragment of tumor cells (thin blue arrow) with stromal core (thick arrow) (hematoxylin and eosin, stain), (b) Microfilariae (red thick arrow) with foamy macrophages (green arrow) (MGG, stain), (c) Tumor cells with vacuolated cytoplasm (blue arrow) and necrosis(red arrow) (hematoxylin and eosin, stain), (d) Tumor cells (blue arrow) with microfilariae (hematoxylin and eosin, stain)

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  Discussion Top

Filariasis is an infectious tropical disease. It is endemic worldwide, and more than 120 million people are infected and one billion people are at risk for infection. Filariasis is caused by the bite of infected mosquito Culex and Anopheles, or rarely by other arthropods. When mosquito bite, larvae of microfilariae get introduced in the host body, which grow into adult forms. This adult form lives in lymphatic vessels, and female forms circulated during the night. When the mosquito bites an infected host, it carries microfilariae which develop into adult forms. If the same mosquito bites a healthy individual, worms are transmitted to the individual and the infection spreads. Hence, definitive host for parasites is humans, while mosquito acts as an intermediate host.[4]

Clinically, initial symptoms are fever, hematuria, increased eosinophils in blood, pain, and redness in affected lymphatics and later stage terminated to elephantiasis. Laboratory diagnosis includes peripheral blood films examination of microfilariae (thick and thin peripheral blood films) and serological test of filarial antigen or antibody testing. Adult worms can be seen in lymphatics, organs, subcutaneous tissues, and serous cavities.[5]

The mechanism by which these worms come to extravascular tissue is poorly understood. However possible mechanism is the boring ability of microfilariae through vascular endothelial spaces and reason for the presence of microfilariae in various organs FNAC aspirate cytosmears.[6] The present case was amicrofilaremia as microfilariae was not demonstrated in peripheral blood smear of the patient, which rules out the possible contamination of blood.

RCCs are most commonly seen in adults between 50 and 60 years of age with male preponderance. RCC consists of 85% of all malignant kidney tumors. The classic triad of renal carcinomas is hematuria, abdominal mass, and flank pain. However, in one-fourth of the cases, RCC is asymptomatic and incidentally diagnosed on routine health checkup ultrasound.[7] Three types of cytomorphology are seen in RCC (clear cell type, granular, and oncocytic). The present case show clear cell variant of RCC because of the presence of abundant vacuolated cytoplasm.[8]

The treatment of choice in RCC is surgical excision. Pallative treatment with radiotherapy and chemotherapy is an optional for advanced disease.[9]

  Conclusion Top

Microfilariae incidentally seen in FNAC from various sites of human body, however microfilariae in renal mass FNAC diagnosed as renal cell carcinomas are rare and its association not related to oncogenesis. Careful microscopic examination of cytosmears picked microfilariae even in situ ation where clinician are not suspected the disease. The early recognition helps to prevent morbidity related to filariasis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Chatterjee KD. Phylum Nemathelminthes: Class Nematoda. In: Chatterjee KD, editor. Parasitology in relation to clinical medicine. 13th ed. Calcutta: CBS Publishers and distributors; 1980. p. 237-8.  Back to cited text no. 1
Gupta S, Gupta R, Bansal B, Singh S, Gupta K, Kudesia M. The significance of the incidental detection of filariasis on aspiration smears: A case series. Diagn Cytopathol. 2010;38:517-20.  Back to cited text no. 2
Linsk JA, Franzen S. Aspiration cytology of metastatic hypernephroma. Cytol. 1984;28: 250-60.  Back to cited text no. 3
Park K. Epidemiology of communicable diseases. In: Park K, editor. Park's text book of preventive and social medicine. 21st ed ed. New Delhi: Bhanot publishers; 2011. p. 245-6.  Back to cited text no. 4
Varghese R, Raghuveer CV, Pai MR, Bansal R. Microfilariae in cytologic smears: A report of six cases. Acta Cytol 1996;40:299-301.  Back to cited text no. 5
Pradhan S, Lahiri VL, Ethence BR, Singh KN. Microfilariae of Wucheria bancrofti in bone marrow smear. Am J Trop Med Hyg 1976;25:199–200.  Back to cited text no. 6
Peterson RO. Kidney, In Urologic Pathology. Philadelphia, JB Lippincott; 1986. p. 1-179.   Back to cited text no. 7
Orell SR, Sterret GF, Whitaker D, editors. Manual and atlas of fine needleaspiration cytology. 4th edition, Delhi: Elsevier, 2005, p. 337-60.  Back to cited text no. 8
Thoroddsen A, Gudbjartsson T, Jonsson E, Gislason T, Einarsson GV. Operative mortality after nephrectomy for renal cell carcinoma. Scandinavian Journal of Urology and Nephrology 2003;37:507-11.  Back to cited text no. 9


  [Figure 1], [Figure 2], [Figure 3]


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