Hydatid cysts - musculoskeletal

Case contributed by Dr Ammar Haouimi


Chronic left pelvic pain with swelling of the ipsilateral gluteal regin in a patient of rural origin. The upper abdominal ultrasound and chest radiograph were normal.

Patient Data

Age: 40 years
Gender: Male

Large expansile multiloculated cystic mass of the left iliac bone, extending to the acetabular roof with cortical thinning and destruction. The cystic matrix shows a variable density (from 5 to 25 HU) with areas of calcification and no enhancement seen on postcontrast images. Others multiloculated intramuscular cysts (some of them are partially calcified) of the left external oblique, iliopsoas, obturator internus and gluteus medius muscles as well as subcutaneous adjacent to the left gluteus medius muscle.

Case Discussion

The MRI features of multiloculated cystic mass of the left iliac bone with adjacent intramuscular cysts in a patient of rural origin is highly suggestive of a hydatid cysts.

Musculoskeletal hydatid infections are a very rare form of hydatid disease. Patients usually present with slow-growing swelling with or without pain. They can present almost anywhere, but most common locations are vertebrae/para-vertebral soft tissue, pelvis, femur and soft tissue of lower limb.

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