We present a case of a patient complaining of pain at the right thigh. A hydatid cyst was diagnosed by a combination of clinical history, imaging , and serologic tests.
A 45-year-old male patient was admitted to the hospital suffering for six months of persistent pain which he described as dull in nature and extending from the right knee to the hip. His medical history was unremarkable and physical examination revealed no abnormal findings. Radiographs revealed an oval cyst with a diameter of 6,5 cm located in the diaphyseal and metaphyseal part of the right femur (Fig 1). CT scan (Figures 2, 3) revealed a hypodense bone lesion without clear boundaries, or periosteal reaction . Coronal MRI showed a large bone lesion hypo T1 and hyper T2 weighted extending from the left femoral neck to the upper third of the femoral diaphysis (Figures 4, 5). The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were 80 mm/h, and 48 mg/dl, respectivel. The Echinococcus latex agglutination test was 1/256 + titers.
Surgical exploration of the right femur revealed a metadiaphyseal cyst. After retraction of the soft tissues, a 1 cm width of the cortex was removed between the trochanteric region to the supracondylar area of the left femur. The entire medullary cavity including the femoral neck was irrigated with hypersaline solution, and was removed atraumatically. The medullary cavity was then curetted meticulously. The defect in the right femur was filled with bone cement. Pathology results of clear fluid aspirated from the cyst, revealed a hydatid cyst of the femur. No evidence of recurrence was observed 18 months after surgery.
Hydatid disease develop in almost any part of the body, bone localisation is rare comprising 0.5-2.5% of all human hydatidosis. In 1884, Thomas [5] published a serie of 28 cases of hydatid bone disease gathered from isolated reports in the literature. Ivanissevich [6] reviewed 47 cases and published the most detailed work on the condition. More recently, Sapkas et al. [1] reviewed cases of hydatid bone disease in different anatomical locations with follow-up periods from 4 to 16 years, and discussed many related diagnostic and therapeutic problems.
The limited publication on hydatid bone disease testifies to the rarity of this condition even in endemic countries [2, 4]. Hydatid bone disease is often asymptomatic and therefore usually diagnosed in an advanced stage when lesions have become extensive [4] like in the present case. The initial location of the lesion in long bones is metaphyseal or epiphyseal, later extending to the diaphysis. Diagnosis is primarily based on findings of radiography and CT scans. Radiography findings include monolocular, bilocular or multilocular cysts. Multilocular cysts, as in this case, are rarely observed and are characterised by oval or polycyclic nonspecific lacunae of variable sizes [4, 7, 8]. CT and MRI are important in determining the accurate extent of the bone and soft tissue abnormalities. Progression of the disease takes place in formation of diverticuli and exogenous vesiculation [7, 8]. Potential complications include pathological fracture, infection, and fistulisation of the abscess. Hydatid bone disease should be considered in the differential diagnosis of osteolytic lesions, especially in endemic areas. Differential diagnoses include chronic osteomyelitis, fibrous dysplasia of bone, osteosarcoma and benign cystic lesions.
The presence of a periosteal reaction, osteosclerosis and calcification are not specific for hydatid bone disease [4, 9]. Surgery is the treatment of choice for hydatid bone lesions. Many authors have advocated wide resection of the involved bone along with the surrounding soft tissue as the only definitive treatment of the condition [3, 4] with or without chemotherapy using albendazole or mebendazole.
Hydatid Disease of the right Femur
Based on the provided X-ray, CT, and MRI images, a noticeable polycystic bone destruction lesion is observed in the proximal right femur (mainly involving the femoral head and the trochanteric region), appearing multilocular or honeycomb-like. The local boundary is relatively unclear, with a fairly extensive area of destruction, and partial soft tissue involvement is noted. Specific characteristics include:
Given the patient is a 45-year-old male presenting with right thigh pain, and serological tests positive for echinococcosis (hydatid disease), the following diagnoses or differential diagnoses should be considered:
Taking into account the patient’s epidemiological background (possibly from or having resided long-term in an echinococcosis-endemic area), clinical symptoms (thigh pain), seropositivity, and radiological findings (multiple cystic bone lesions extending into soft tissue), the most likely diagnosis is:
Osseous Echinococcosis (Hydatid Bone Disease)
As bone echinococcosis is relatively rare and its imaging findings can mimic other cystic lesions, specific serological testing and pathological biopsy (if feasible) are usually required to confirm the diagnosis.
1. Surgical Treatment: For osseous echinococcosis, complete and thorough surgical removal or curettage is the most definitive treatment approach. Depending on the extent of the lesion, extensive resection of the affected bone tissue and subsequent reconstruction (such as joint replacement) may be necessary. During the operation, efforts should be made to prevent cyst rupture in order to avoid dissemination.
2. Medical Therapy: Pre- and post-operative anti-echinococcal medications (e.g., albendazole or mebendazole) can help reduce recurrence and control the spread of residual parasites. The treatment course is generally prolonged and can last for several months.
3. Rehabilitation Plan and Exercise Prescription:
This report is a reference-based analysis based on the provided imaging and textual information and is not a substitute for in-person consultation or professional medical advice. If you have any questions or experience any changes in symptoms, please seek prompt medical attention for a comprehensive and accurate diagnosis and treatment plan.
Hydatid Disease of the right Femur
