Hydatid cyst in the vastus lateralis muscle: a case report

Abstract

SummaryHydatidosis is a zoonotic disease; human infection occurs through the consumption of food and water contaminated with the eggs of parasites of the Echinococcus type. While the liver is the most common site of infection, involvement of the musculoskeletal system is extremely rare. In the context of musculoskeletal involvement, the spine is the most commonly infected site, while the muscles are rarely infected and account for approximately <1% of cases. It has been suggested that muscles provide an unsuitable environment for the parasite, because of the presence of lactic acid. The cysts appear as slow-growing masses of soft tissue, and signs of inflammation and fistulization often coexist. We report a rare case of an hydatid cyst located in the vastus lateralis muscle of a 41-year-old man. Muscular echinococcosis is an extremely rare disease. A MRI evaluation should be taken into account as gold standard in the diagnosis. Surgical cystectomy is often indicated, and an excision with wide margins is mandatory to avoid the rupture of the cyst and anaphylaxis. Adjuvant pharmacological therapy is recommended to minimize the risk of recurrence.

Bone and Intramuscular Hydatid Cysts: A Rare Association

“…Echinococcosis or hydatidosis is caused by the cestode Echinococcus in its larval stage [4]. The disease is particularly common in Asia, North and East Africa, South America, Australia and the Middle East [2]. It is more common in those who are engaged in agriculture and animal husbandry, and those in contact with dogs [7].…”

“…It contributes, as well as the chest x-ray, to the assessment of hydatid disease, to the search for associated visceral locations that may guide the diagnosis [9]. CT and essentially MRI imaging play a key role in hydatid disease diagnosis [2]. They determine the bone damage, assess the locoregional extent and constitute an excellent means of monitoring the disease progression [9].…”

“…MRI scans show the daughter cysts with high signal intensity or low signal intensity in T2-weighted images. The lower signal intensity of daughter cysts compared with the matrix of the mother cyst in T2-weighted images is a sign of the parasite death [2]. However the computed tomography still the best tool to characterize bone lytic lesion, cortical destruction and for detecting cystic wall calcification and revealing the internal cystic structure posterior to calcification in soft tissue locations.…”

“…For Muscular echinococcosis, surgical treatment consisting of the cyst excision and pericystectomy are the treatment of choice [2]. While, the current treatment for bone location is medico-surgical [5].…”

“…It occurs either through direct ingestion of parasite eggs from contact with infected dogs or indirectly from the ingestion of contaminated water or food. Hepatic and pulmonary localizations are the most frequent, while the involvement of the musculoskeletal system is extremely rare [1,2]. Bone hydatidosis represents 3% of locations [3].…”