|Year : 2016 | Volume
| Issue : 2 | Page : 109-111
Primary hydatid cyst in the deeper plane of the sternocleidomastoid muscle of the neck diagnosed on fine needle aspiration cytology: A case report
Madhu Kumar, Yatendra Parashar, Anju Bharti
Department of Pathology, King George’s Medical University, Lucknow, Uttar Pradesh, India
|Date of Submission||04-May-2016|
|Date of Acceptance||04-Jul-2016|
|Date of Web Publication||25-Apr-2017|
Department of Pathology, King George’s Medical University, Shahmina Road, Lucknow 226003, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Hydatid disease is caused by Echinococcus granulosus, and the commonly affected organs are the liver and lung. The musculoskeletal or soft tissue involvement accounts for about 0.5–5% of all cases in endemic areas. This case report indicates that hydatid cyst should be considered in the differential diagnosis of benign cystic swelling in the head and neck region. We report this case of a 32-year-old female patient with an unusual presentation of a swelling in the deeper plane of the sternocleidomastoid muscle in the neck and diagnosed by means of fine needle aspiration cytology.
Keywords: fine needle aspiration cytology, hydatid cyst, neck muscle, unusual site
|How to cite this article:|
Kumar M, Parashar Y, Bharti A. Primary hydatid cyst in the deeper plane of the sternocleidomastoid muscle of the neck diagnosed on fine needle aspiration cytology: A case report. Parasitol United J 2016;9:109-11
|How to cite this URL:|
Kumar M, Parashar Y, Bharti A. Primary hydatid cyst in the deeper plane of the sternocleidomastoid muscle of the neck diagnosed on fine needle aspiration cytology: A case report. Parasitol United J [serial online] 2016 [cited 2017 Oct 22];9:109-11. Available from: http://www.new.puj.eg.net/text.asp?2016/9/2/109/205171
| Introduction|| |
Hydatid disease is a helminthic infection caused by the larval form of a tapeworm of the genus Echinococcus. Its eggs are discharged in the feces of the definitive host and may infect humans as natural intermediate host. Hydatid cysts commonly involve the liver and lungs and are uncommonly found in muscles, even in endemic zones . Musculoskelatal or soft tissue hydatidosis accounts for about 0.5–5% of all echinococcal infections in endemic areas and is almost always secondary to liver or lung disease . We report a unique case of hydatidosis that was diagnosed by means of fine needle aspiration cytology (FNAC) in the neck region without involvement of the liver or lung.
| Case report|| |
A 32-year-old female patient presented with a painless swelling in the deeper plane of the sternocleidomastoid muscle of the neck [Figure 1] of 4-month duration. Initially, she had noticed the swelling when it was about 1 cm in size, and then it gradually increased to reach the presenting size of about 2 cm. There was no history of contact with dogs or any other animal. On examination, the swelling was well defined, soft, cystic, mobile, and nontender. With a clinical diagnosis of tubercular lymphadenitis, the patient was sent to our department for FNAC. Hemogram was unremarkable. With the patient’s consent, 4 ml of blood mixed serous fluid was aspirated. The fluid was centrifuged, and the sediment was smeared on slides and stained with May-Grunwald Giemsa and hematoxylin and eosin (H&E). On microscopic examination, the smears showed fragments of an eosinophilic laminated wall with numerous hooklets and scolices in a dirty inflammatory background mixed with blood ([Figure 2]a and [Figure 2]b). The cytomorphological diagnosis was hydatid cyst. The patient underwent chest radiography and abdominal ultrasonography to rule out other organ involvement. Investigation did not reveal any hydatid cyst in the brain, liver, lung, or spleen, thus indicating that this was a case of primary hydatid cyst of the neck. After FNAC, no allergic reactions developed. The patient underwent surgery and was treated with albendazole 400 mg twice daily for 1 month postoperatively. After histopathological processing of the surgically removed cyst, the diagnosis of hydatid cyst was confirmed.
|Figure 1 Painless swelling in the deeper plane of the sternocleidomastoid muscle of the neck.|
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|Figure 2 (A) Microscopic examination of fine needle aspiration cytology (FNAC) aspirate shows numerous hooks and scolices in the inflammatory background mixed with blood (H&E stain, ×100). (B) Microscopic examination of FNAC aspirate shows fragments of eosinophilic laminated wall with numerous hooks (H&E stain, ×400, Inset shows a hook).|
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| Discussion|| |
Hydatid disease is seen endemically in many parts of the world, including Africa, India, South America, Turkey, and Southern Europe . The liver accounts for about 70% and the lungs for 25% of cases but hydatid cysts may occur anywhere in the body, including the spleen, kidneys, bile ducts, mesentery, heart, brain, and musculoskeletal or soft tissue . Systemic dissemination through the lymphatics is a strong possibility for the unusual presentation sites including the neck. Primary hydatid disease of the skeletal muscle is rare, as the parasite has to cross pulmonary and hepatic barriers to reach the muscles . The adult worm lives in the small intestine of definitive host (dogs or other carnivores) and discharges a large number of eggs in their feces. Eggs are swallowed by the intermediate hosts while grazing in the field, and also by humans due to intimate handling of infected dogs. In the duodenum, the embryos hatch, penetrate the intestinal wall, and enter into the portal vein. The embryos are carried to the liver to be arrested in the sinusoidal capillaries. Some of the embryos may pass through the hepatic capillaries, enter the pulmonary circulation, and filter out in the lungs. A few of the embryos may pass the pulmonary capillaries, enter the general blood stream, and lodge in various organs, thus affecting all parts of the body . Wherever the embryo settles, it forms a hydatid cyst. The young larva being transformed into a hollow bladder forms the inner side of the cyst from which brood capsules with a number of scolices are developed. Belcadhi et al.  reported 17 cases of head and neck hydatid disease and indicated that FNAC can suggest the diagnosis by aspirating clear fluid characteristic of hydatid disease, but advised caution in its use for routine evaluation of suspected hydatid cysts, to avoid anaphylactic shock or dissemination of infection. In the head and neck, especially in the thyroid region, one more case was diagnosed by means of FNAC; the final diagnosis of hydatid cyst was confirmed by histopathology . Albendazole therapy is recommended for prophylaxis against preoperative contamination risk .
To the best of our knowledge, very few cases have been reported in the literature on hydatid cyst of the head and neck region involving muscles. Our case was unique because it was diagnosed by means of FNAC in the neck region without involvement of disease in any other organ. To conclude, when diagnosing a cystic swelling of muscle plane, the possibility of hydatid disease should always be considered.
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[Figure 1], [Figure 2]