Page mackup January-14.qxd 99 Bangladesh Journal of Medical Science Vol. 13 No. 01 January’14 Introduction Among other tropical diseases, filariasis is a major public health problem in the African and Asian sub- continent. It is transmitted by the Culex mosquito and is caused by two closely related nematodes: Wuchereria bancrofti and Brugia malayi. Filariasis affects the lymphatic system with a predilection for lower limbs, retroperitoneal tissues, spermatic cord, and epididymis1. Filaria can affect other sites rarely. Though single or small number of cases on microfi- laremia at various sites as lymphnode, breast lump, bone marrow,bronchial aspirates, nipple secretion, pleural and pericardial fluid, ovarian cyst fluid and cervico vaginal smear have been reported, thyroid is another site from which microfilaria has been isolat- ed. So far only nine case reports are available. It is estimated that approximately 600 million people are living in areas endemic for lymphatic filariasis Southeast Asia Region. There are approximately 60 million people infected in the region and approxi- mately 31 million people have the clinical manifes- tation of this disease2. Here we present a patient with filariasis of the thy- roid detected by Fine needle aspiration cytology (FNAC) of thyroid gland. Case Presentation A 36-year-old female presented with a slowly enlarging painless swelling of thyroid gland over a period of two years. Clinically patient had no other complain. Thyroid function was normal. On exami- nation a 3×3 cm, firm, non-tender thyroid nodule was palpable over left lobe. No cervical lymph node was palpable. Fine-needle aspiration of the thyroid nodule revealed blood mixed colloid. Slides were stained with Leishman-Giemsa stain. Microscopic examination of the smear showed the presence of microfilarial larvae with few mono-lay- ered clusters of benign follicular cells in the back- ground of blood mixed colloid. The microfilariae had blunt head and pointed tail with a sheath project- ed slightly beyond the extremities of the embryo (Fig.1). Somatic cells or nuclei appeared as granule in the central axis of the body and were absent at the tip of the tail. All the features distinguish M. ban- crofti from the other sheathed larvae. Discussion Filariasis is a global problem. It is also a major health problem in India3 .This patient also presented as euthyroid state similar to the findings of Kundu Case report: A rare case of microfilaria in thyroid aspirate Mondal RK1, Ray R2, Kawsar H3, Ali MS4. Abstract Filariasis is a major health problem in the Indian Subcontinent. Due to its nocturnal periodici- ty it may be difficult even to demonstrate in the blood. In heavy parasitic load they may appear in the blood, urine with chyle and at times in scrotal aspirates. It is very rare and unusual to find microfilaria in thyroid aspirate. This case report of presence of microfilaria in thyroid aspirate suggest that careful screening is important for thyroid lesions as patients may present with thyroid enlargement other than usual thyroid lesions. Key words: microfilaria, thyroid, FNAC Corresponds to: Dr.Rajib Kumar Mondal, Assistant Professor, Dept. of Pathology, Vill-Barjora, Schooldanga, Po+ps-Barjora, Dist-Bankura, WestBengal, Pin-722202, India, Email: rajibkmondal@yahoo.co.in 1. Mondal Rajib Kumar, Assistant Prof,BSMCH 2. Ray Rudranarayan, Assistant Prof,BSMCH 3. Kawsar Hena, PGT, BSMCH 4.Ali Md. Sadakkas, Resident Surgeon, NRS Medical College, Kolkata DOI: http://dx.doi.org/10.3329/bjms.v13i1.14217 Bangladesh Journal of Medical Science Vol. 13 No. 01 January '14 Page 99-100 et al, Kar D.K. et al and Mohanti et al4,5,6. In no case reported previously suspect of microfilaria was made. All the cases were sent for FNAC for diagno- sis of other primary lesions similar to our case2. The clinical manifestations of lymphatic filariasis may range from asymptomatic microfilariasis to hydrocele, lymphangitis, lymphadenitis with high- grade fever (filarial fever), and lymphatic obstruc- tion7. In our case it presented with asymptomatic thyroid swelling, similar findings have been noted by study of Mohanti et al and Vargese et al6,8. Microfilaria of thyroid has never been suspected in any case reports including those cases where high eosinophilia has been reported2. There are eight identified species of filarial parasite among them only three (i.e., W. Bancrofti, B. Malayi, and Brugia timori) are known to cause lymphatic filariasis . These are sheathed species. In India microfilariae bancrofti and microfilariae malayi are the commonly prevalent species. Species diagnosis is made on the basis of morphology of the microfi- laria. Microfilariae of B. Malayi are smaller than those of W. bancrofti, possess secondary kinks instead of a smooth curve, and unlike the latter, the tip is not free of the nuclei9. Conclusions In conclusion, filariasis of the thyroid is an uncom- mon condition and need a high index of suspicion and careful screen of FNA smears especially in asymptomatic patients belonging to endemic zones, so as not to miss this incidental finding especially in patients from endemic areas . References 1. Faust EC, Russell PF, Jung RC. Craig and Faust's Clinical Parasitology, 8th ed. Philadelphia: Lea & Febiger; 1970. 2. Chowdhary M, Langer S, Aggarwal M, Agarwal C. Microfilaria in thyroid gland nodule. Indian J Pathol Microbiol. 2008 ; 51(1):94-6 PMid:18417874 http://dx.doi.org/10.4103/0377-4929.40415 3. Park K.Textbook of Preventive and Social Medicine. 21st ed. Jabalpur: Banarsidas Bhanotn; 2011. 4. Kundu AK, Giri A, Ghosh G, Saha SR. Microfilaria in a thyroid nodule which resolved on treatment.Trop Doct. 2002 ;32(4):248 PMid:12405321 5. Kar DK, Agarwal G, Krishnani N, Mishra SK. Microfilaria in thyroid: A histopathological encounter. Thyroid 2001 ;11(4):401 http://dx.doi.org/10.1089/10507250152039172 PMid:11349842 6. Mohanty SK, Patnaik S, Dey P. Microfilaria in thyroid aspirate. Diagn Cytopathol 2002;26(3):197-8 h t t p : / / d x . d o i . o r g / 1 0 . 1 0 0 2 / d c . 1 0 0 5 2 PMid:11892028 7. Maheshwari V, Khan L, Mehdi G, Zafar U, Alam K. Microfilariae in thyroid aspiration smear—an unex- pected finding. Diagn Cytopathol. 2008 ; 36(1):40-1. h t t p : / / d x . d o i . o r g / 1 0 . 1 0 0 2 / d c . 2 0 5 4 9 PMid:18064692 8. Varghese R, Raghuveer CV, Pai MR, Bansal R. Microfilariae in cytologic smears: A report of six cases. Acta Cytol 1996;40 (2):299-301 h t t p : / / d x . d o i . o r g / 1 0 . 1 1 5 9 / 0 0 0 3 3 3 7 5 5 PMid:8629415 9. Chatterjee KD. Parasitology. 13th ed. New Delhi: CBS Publishers; 2009. 100 Microfilaria in thyroid aspirate