Is Hydatid Cyst with Musculoskeletal Involvement a Problem that Causes Morbidity? Long-Term Follow-Up and Functional Results

Magnetic resonance imaging characteristics of musculoskeletal hydatid disease

BACKGROUND

Hydatid disease is a parasitic infection seen in endemic areas. Musculoskeletal hydatid disease is rarely reported.

PURPOSE

To describe the magnetic resonance imaging (MRI) features of musculoskeletal hydatid disease and to highlight the specific findings in the diagnosis of hydatid cysts.

MATERIAL AND METHODS

The MRI scans of 29 cases diagnosed as musculoskeletal hydatid disease between 2000 and 2022 were retrospectively analyzed. The localization, size, appearance (unilocular or multilocular), signal characteristics, rim sign, presence of internal septa and membrane, and gadolinium enhancement pattern of hydatid cysts were evaluated.

RESULTS

A total of 29 patients diagnosed with hydatid cyst were included in the study. Of the lesions, 18 were localized in bone and 11 were in soft tissue. The bone hydatid cysts on MRI showed heterogeneous low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images in the medullary bone. In 15/18 patients, there was also cortical destruction and extension into the adjacent soft tissue planes. In 8/11 cases where the cyst was located in muscle tissue, the "cyst or cysts within a cyst" appearance was observed on MRI. The rim sign was observed in 7/11 cases and the "water lily" sign was noted in 2/11 cases.

CONCLUSION

MRI provides valuable information for the diagnosis of hydatid disease with its distinctive imaging features. Knowledge of the different patterns of hydatid cysts on MRI may be helpful in the diagnosis of this disease.

An Unusual Cause of Insidious Back and Shoulder Pain in a Man: A Case Report

Hydatid cyst is an infestation caused by Echinococcus granulosus, which is endemic in most countries and most commonly affects the liver and lungs. Isolated muscle involvement is very rare and accounts for 3-5% of all cases. In April 2022, Health Sciences University Elaziğ Fethi Sekin City and Research Hospital in Turkey received a referral for a 37-year-old male patient from the physical therapy and rehabilitation outpatient clinic. The patient presented with complaints of chronic pain in his left shoulder and back, which worsened with movement. After the radiological and serological confirmation of diagnosis, the patient underwent wide surgical resection, adjuvant and neoadjuvant anthelmintic chemotherapy. Precise and complete removal of the cyst without infecting the surrounding tissues combined with anthelmintic chemotherapy will not only increase the success of the surgery but will also minimize the possibility of recurrence and distant organ spread. In this study, we aimed to raise awareness by presenting the first reported isolated hydatid cyst in the infraspinatus muscle case from our country, which is extremely rare.

Diagnostic Approach and Differences between Spinal Infections and Tumors

STUDY DESIGN

A systematic review of the literature about differential diagnosis between spine infection and bone tumors of the spine.

BACKGROUND AND PURPOSE

The differential diagnosis between spine infection and bone tumors of the spine can be misled by the prevalence of one of the conditions over the other in different areas of the world. A review of the existing literature on suggestive or even pathognomonic imaging aspects of both can be very useful for correctly orientating the diagnosis and deciding the most appropriate area for biopsy. The purpose of our study is to identify which imaging technique is the most reliable to suggest the diagnosis between spine infection and spine bone tumor.

METHODS

A primary search on Medline through PubMed distribution was made. We identified five main groups: tuberculous, atypical spinal tuberculosis, pyogenic spondylitis, and neoplastic (primitive and metastatic). For each group, we evaluated the commonest localization, characteristics at CT, CT perfusion, MRI, MRI with Gadolinium, MRI diffusion (DWI) and, in the end, the main features for each group.

RESULTS

A total of 602 studies were identified through the database search and a screening by titles and abstracts was performed. After applying inclusion and exclusion criteria, 34 articles were excluded and a total of 22 full-text articles were assessed for eligibility. For each article, the role of CT-scan, CT-perfusion, MRI, MRI with Gadolinium and MRI diffusion (DWI) in distinguishing the most reliable features to suggest the diagnosis of spine infection versus bone tumor/metastasis was collected.

CONCLUSION

Definitive differential diagnosis between infection and tumor requires biopsy and culture. The sensitivity and specificity of percutaneous biopsy are 72% and 94%, respectively. Imaging studies can be added to address the diagnosis, but a multidisciplinary discussion with radiologists and nuclear medicine specialists is mandatory.

Imaging Manifestations and Misdiagnosis Analysis of Six Cases of Bone Hydatid Disease

We retrospectively evaluated the clinical and imaging features of 6 patients with bone hydatid disease confirmed by surgery and pathological examination. Among the 6 patients, 2 were infected with Echinococcosis granulosus metacestode and 4 were infected with E. multilocularis metacestode. The 2 cases with cystic echinococcosis were diagnosed by computed tomographic (CT) examination, and other 4 cases were diagnosed by magnetic resonance (MR) imaging. On the initial evaluation, 1 case each was misdiagnosed as a giant cell tumor or neurogenic tumor, and 2 were misdiagnosed as tuberculosis. The imaging manifestations of bone hydatid disease are complex, but most common findings include expansive osteolytic bone destruction, which may be associated with sclerosing edges or dead bone formation, localized soft tissue masses, and vertebral lesions with wedge-shaped changes and spinal stenosis. Combining imaging findings with the patient's epidemiological history and immunological examinations is of great help in improving the diagnosis and differential diagnosis of bone hydatid disease.