A 91-year-old woman admitted to the emergency department with shivers, general malaise and suspicion of urinary tract infection. Patient associated also a soft, painful mass in right inguinal region. Many abdominal scars from previous surgeries were seen at the physical exploration as a result of previous cyst removals dated 20 years ago (retroperitoneal hydatidosis). A blood test revealed leukocytosis with neutrophilia, and the urine test showed pathological urine sediment with no pathologic cells.
Initial imaging with US was done and after that, a contrast-enhanced abdominal CT was performed. In the right pelvis, we can see a retroperitoneal multiloculated lesion with soft-tissue involvement (Fig. 1) that extends from the right iliac bone. In the posterior abdominal wall, we see another multiloculated lesion that extends from the right iliac bone to the subcutaneous space. Both lesions have multiple homogenous hypodense thin wall cysts (Fig. 1). We can appreciate that the lesion has produced multiloculated bone remodulation with no periosteal reaction (Figs. 2 and 3). With these imaging findings and the clinical history of the patient, the diagnosis of active hydatidosis was established. Due to the age of the patient, the treatment was non-surgical with echinococcus targeted antibiotherapy.
Hydatidosis or echinococcosis is a cyclozoonosis caused by tapeworm Echinococcus granulosus larvae (1). Humans are accidental intermediary hosts, infected by direct contact with other infected animals (sheep, dogs, goats, cows) or indirectly, mainly due to ingestion of contaminated water or vegetables.
Once the intake of the larvae is produced, because of duodenum digestion the scolex are liberated into the intestinal tract. Those scolexes go through the intestinal wall reaching the venous and lymphatic system (1). The liver is the first line of defence and the most involved organ due to the fact that here most of them are eliminated by the immune system. Due to haematogenous spread, the scolex can reach almost every anatomic structure.
Hydatidosis diagnosis is based on cyst identification with imaging techniques and detection of specific serum antibodies, with tests like ELISA (high sensibility) and immunoelectrophoresis (high specificity) (2). It is important to keep in mind that depending on the cyst stage, it could be false negative, and we cannot dismiss the possibility of infection.
The “WHO-Informal Working Group on Echinococcosis” (WHO-IWGE) OMS 2003 radiology classification (3) is based on the morphology of the cyst seen by ultrasonography, it divides them in three categories: active, in degeneration and inactive. It is a simple classification that expects to unify the diagnosis (including by CT or MRI) (4) and simplify the treatment of hydatidosis,
Bone hydatid disease is a very rare clinical and radiological diagnosis (0,5 - 2% of cases) (5). Normally affects the spine, pelvis, femur or tibia. Bone cysts adopt irregular and ramified forms because they expand through low-resistance areas. Commonly cysts have a thinner wall, and in the bone is seen as a lytic, well defined lesion, with no periosteal reaction, typically multiloculated and expansive (6). As time goes by, bone cortical thinning is produced so much that it could even break and extend into contiguous soft tissues. If this happens, it can appear soft tissue calcifications. Pathological fractures are relatively common. The best imaging technique to evaluate the bone damage is CT.
Surgical excision (pericystectomy) is the treatment of choice in bone hydatid disease. To reduce cyst dimensions and to limit the infectious process it is preferred to administer Albendazol associated with chemoprophylaxis preoperatively (6). In inoperable cases the treatment can be pharmacological or percutaneous with PAIR technique (puncture, aspiration, injection and reaspiration) (3).
An early diagnosis of bone hydatid disease it is essential, considering that the advanced forms are hard to treat (even clinical or surgically) (7).
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Bone hydatid disease
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Based on the provided abdominal and pelvic CT images, multiple lesions with relatively clear boundaries, appearing cystic or multilocular, can be observed in the pelvic region (especially in the iliac bone and adjacent soft tissues). The local cortical bone appears thinned and partially destroyed, and some cystic lesions show soft tissue expansion. Certain cyst walls are rather thin, and the bone areas exhibit lytic changes without a clear periosteal reaction.
Considering the patient's past medical history (surgical resection for retroperitoneal echinococcosis about 20 years ago) and the current clinical presentation (a soft, tender mass palpable in the inguinal region), possible recurrence or residual echinococcal lesions with bony invasion is suggested. Furthermore, a certain degree of soft tissue shadow is noted around the area of bone destruction, indicating the lesion may occasionally extend into the adjacent soft tissues.
Considering the patient’s advanced age, history of echinococcosis surgery, clinical symptoms (inguinal mass, pain), and imaging findings of multilocular lytic lesions, the most probable diagnosis is bone echinococcosis (osseous echinococcosis). Further confirmation can be pursued through serological testing (echinococcal antibody detection) or histopathological examination (biopsy).
In the context of bone echinococcosis or other conditions causing bone destruction, rehabilitation should consider skeletal load-bearing capacity and overall physical function. Recommended approaches include:
In summary, early and continuous antiparasitic therapy combined with surgical intervention can help reduce the risk of disease progression. A well-designed rehabilitation program can aid in preserving muscle strength and improving overall quality of life.
This report is based solely on the provided information and is intended for reference only. It does not replace an in-person consultation or the judgment of a professional physician. Patients are advised to develop and adjust the final treatment and rehabilitation plan in consultation with specialized healthcare professionals.
Bone hydatid disease
