Intracranial hydatid cyst: imaging findings of a rare disease

Abstract

Hydatid disease (echinococcosis) is a worldwide zoonosis produced by the larval stage of the Echinococcus tapeworm. The disease is endemic in many parts of the world, particularly in the Middle East, Australia, New Zealand, South America and central and south Europe. Intracranial hydatid disease is considered a rare disease and may be sometimes very difficult to diagnose based on the clinical and laboratory findings. Therefore, it is important to be aware of the condition and the imaging findings even in the non-endemic parts of the world. We report the case of a 12-year-old boy who presented with headache and vomiting for a few months. The mass was totally excised, with no postoperative complications. We present MR spectroscopy (MRS) findings in this operatively proven case of hydatid cyst of the brain. We discuss imaging findings, in particular the findings on MRS, which is rarely reported in the literature.

Intracranial hydatid disease

“…The diagnosis of intracranial hydatid relies on radiological investigations. On CT head, there is hypodense non contrast enhancing oval homogenous cystic mass lesion with thin walls and smooth margins usually in territory of middle cerebral artery with pressure effect on surrounding brain parenchyma as per the size of lesion with no surrounding edema [10,30] . Usually upon diagnosis the lesions are of considerable size before symptoms appear as intracranial hydatid cyst is a slow growing lesion although a variable growth rate of 1-10 cm/ year has been documented in literature [23,9,14,28] .…”

“…On MRI brain, cyst wall has low signal intensity on both T1 and T2 imaging with no enhancement, daughter cysts or hydatid sand may be visible on MRI, no rim enhancement is a differentiating feature from cystic high grade tumours or abscess [10,30] . Infiltrating margin and surrounding edema may be a feature of echinococcus multilocularis.…”

“…No patient in current series was subjected to MRS. The various differential diagnosis to be considered on radiology should include cystic tumours, porencephalic cysts, arachnoid cysts, epidermoid cysts, neurocysticercosis, toxoplasma [23,30,5] . Among serological tests immunoblot test is the test of choice targeting the specific arc 5 antigen present in hydatid fluid of E.granulosus.…”

Hydatid brain cyst: A delayed diagnosis in a rural setting during COVID-19

“…Although perilesional oedema is not usually present with hydatid cysts, if it is present, it may indicate a secondary infection or cyst rupture. [13] Smaller 'daughter cysts' within the main cyst can also sometimes be seen, and additional smaller cysts surrounding the main cyst can indicate prior rupture of the main cyst. Unlike liver and lung hydatid cysts, Echinococcus serology can be misleading in the presence of brain cysts and is usually falsely negative owing to minimal immune responses elicited within this privileged site.…”

Concurrent brain and lung hydatid cyst in a paediatric patient: Anaesthetic challenges

“…Intracranial hydatid cyst (HC) is rare, with an incidence of 1%–2%. [ 1 ] We describe the anaesthetic management of intracerebral HC with a concurrent pulmonary cyst.…”