A case of primary cervicofacial hydatidosis.

Sir,

Hydatid disease of the neck region is an extremely rare finding, even in endemic regions, and only a few cases have been reported in the literature.[12345]

A 25-year-old female presented with a 1-month history of gradually progressive swelling in the neck. It was not associated with pain or fever or any other symptom. The swelling was located in the right cervical region, just below thyroid; its size was about 3 × 2 cm and was cystic in consistency. It was non-tender and the overlying skin did not show any signs of inflammation. A submandibular lymph node was also palpable, size approximately 1 × 1cm. X-ray demonstrated a mass in the neck without involvement of deeper structures. Ultrasonography showed a loculated cystic lesion with internal septae near the lower pole of thyroid under the strap muscles of the neck. An excisional biopsy of the mass was performed followed by irrigation by hypertonic saline [Figure 1]. Hematoxylin and eosin (H and E) stained slides were examined which showed all the three layers namely outermost pericyst, laminated layer and the inner germinal layer (which together comprise the endocyst) [Figure 1]. Thus a final diagnosis of hydatid cyst in the neck was made. Biopsy of the lymph node revealed features of reactive lymphadenitis. The patient underwent further investigations and further thorough examination was done. There was no evidence of primary illness anywhere else. Since there was no evidence of primary lesion anywhere else, a final diagnosis of primary hydatid disease of the neck was made. The patient was given 4-week albendazole therapy (400 mg twice a day) and since the cyst was completely excised, no further surgical intervention was done. Presently, she is doing well and there is no evidence of recurrence.

Figure 1

(a) Ultrasound showing a loculated cystic lesion with internal septa near the lower pole of thyroid under the strap muscles of neck. (b) Hematoxylin and Eosin (H and E) stained section of a part wall of hydatid cyst showing laminated layer and outermost pericyst layer composed of granulation tissue (H and E ×40). (c) H and E stained section of a part of cyst wall showing laminated layer and innermost germinal layer (H and E ×100). (d) High power view showing both laminated and innermost germinal layer (H and E ×400)

Due to its rarity, the diagnosis of cervicofacial hydatid disease is difficult.[1234] However, diagnosis can be aided by taking proper history and combining different diagnostic modalities like radiology and serology. Serological tests, include immune hemagglutination, complement fixation, immunoelectrophoresis, skin tests (Casoni intradermal test), enzyme-linked immunosorbent assay (ELISA) and western blot serology. Radiology is a better diagnostic tool than serology.[2] Ultrasonography can clearly demonstrate the hydatid sands in purely cystic lesions, as well as floating membranes, daughter cysts, and vesicles. Some authors discourage the use of fine needle aspiration (FNA) in diagnosing Hydatid disease due to danger of spillage and anaphylaxis.[2] Histopathology is unanimously the preferred and definitive diagnostic option.[23] It consists of an inner germinal layer of cells supported by a characteristic acidophilic-staining, acellular, laminated membrane of variable thickness. Each cyst is surrounded by a host-produced layer of granulomatous adventitial reaction tissue, which is a thick fibrous tissue.[23] The most effective and gold standard treatment of hydatid cyst is surgical excision.[15]