Tumours and tumour-like lesions of the hip in the paediatric age: a review of the Rizzoli experience

Differential diagnosis of hip pain in children referred to a specialist bone tumour service

OBJECTIVE

To determine the differential diagnosis of bone lesions causing hip pain in children and the association between radiographic features of aggression and MRI appearances with final diagnosis.

METHODS

Retrospective review of children with hip pain referred to a specialist musculoskeletal oncology service between September 2018 and December 2020. Patient demographics, lesion location, the radiographic and MRI features, and the final diagnosis, which was made either by image-guided biopsy, surgical curettage or based on typical imaging features were recorded. Statistical analysis examined the association between the Lodwick-Madewell score (determined from available radiographs) and MRI findings with final diagnosis.

RESULTS

Fifty-nine patients were included, 40 males and 19 females with mean age 10.9 years, (range 3-16 years). Final diagnoses were based on histology in 24 (40.7%) cases and imaging in 35 (59.3%) cases. Eighteen lesions (30.5%) were classed as non-neoplastic, 31 (52.5%) as benign and 10 (16.9%) as malignant, of which four were primary bone sarcomas. There was a significant association between the Lodwick-Madewell score and final diagnosis (p < 0.001). On MRI, bone marrow oedema, presence of a focal lesion, bone expansion and the presence of an extraosseous mass were all significantly associated with final diagnostic classification.

CONCLUSION

The differential diagnosis of hip pain in children presenting to a bone tumour service is wide. Most cases are due to benign or non-neoplastic conditions, with only 10 out of 59 children having a malignant lesion. Radiography complemented by MRI plays a major role in differentiating non-neoplastic, benign neoplastic and malignant lesions and in determining the requirement for needle biopsy.

ADVANCES IN KNOWLEDGE

This is the first study to consider how imaging features relate to diagnosis in suspected paediatric hip tumours. Use of this information can help in determining which cases should undergo needle biopsy.

Osteoid Osteoma: A Unique Presentation in a Child's Lesser Toe

Introduction

Osteoid osteoma is an uncommon, small, benign, self-limiting, and usually painful tumor of the skeleton. Diagnosis can be straightforward if seen in the usual locations as the femur and the tibia in young adults, who present with nocturnal pain, alleviated by salicylates. The diagnosis can be more challenging in the spine, pelvis, hand, or feet. Case Report. We report the case of an 11-year-old boy who was treated symptomatically for a painful toe since 10 months, without a definitive diagnosis. X-ray, MRI, and scintigraphy, along with the typical nocturnal pain and swelling of the toe, suggested an osteoid osteoma, confirmed by histology after excisional biopsy of the lesion.

Conclusion

Osteoid osteoma should always be included in the differential diagnosis when it comes to nocturnal pain without systemic signs, even in unusual places in children. The awareness should lead to a prompt diagnosis and treatment.

Synovial cysts of the hip

Background:

Synovial cysts of the hip are relatively rare lesions comparing to other joints. Patients are usually asymptomatic, but in some cases symptoms such as pain and/or compression of vessels or nerve could be present. Purpose of the study was to define clinical features and optimal management of synovial cyst of the hip joint through an accurate review of the literature.

Methods:

We present three consecutive cases treated with three different therapeutic strategies: surgical excision, wait-and-see and needle aspiration. An accurate review of the literature has been performed to identify patients who had been treated for synovial cyst of the hip.

Results:

Due to the rarity of the disease, there are no significant data in literature supporting the gold standard of treatment. Treatment of the synovial cyst depends on their size, symptoms and comorbidities.

Conclusions:

Most of the Authors recommend surgical treatment for symptomatic synovial cysts and needle aspiration as an option treatment in asymptomatic patients without vessel or nerve compression. In patients that referred symptoms in correspondence with the hip joint, not strictly related with radiograph findings, a CT or MRI examinations should be performed to exclude possible differential diagnosis. (www.actabiomedica.it)

Bone and soft tissue tumors of hip and pelvis

Objective is to identify epidemiologic and radiologic criteria allowing specific diagnoses of tumors and tumor-like lesions in the hip region and pelvis, and to optimize pre-operative staging. Patients with pelvic tumors are usually older, and their tumors are larger relative to patients with tumors in extremities. The majority of tumors in the pelvis are malignant (metastases, myeloma, chondrosarcoma, Ewing-, osteo-, and MFH/fibrosarcoma), while those in the proximal femur are in majority benign (fibrous dysplasia, solitary bone cyst, and osteoid osteoma). Soft tissue masses in the thigh in the elderly are typically sarcomas without tumor specific signs. Common tumor-like lesions occurring in the hip and pelvis that can mimic neoplasm are: infections (including tuberculosis), insufficiency/avulsion fractures, cysts, fibrous dysplasia, aneurysmal bone cyst, Langerhans cell histiocytosis, and Paget's disease. Local MR staging is based on the compartmental anatomy. The psoas and gluteal muscles are easily invaded by sarcoma originating in the ileum. The pectineus muscle protects the neurovascular bundle at the level of the hip. The thigh is separated into three compartments, some structures (Sartorius muscle) cross borders between compartments. Immobile joints (SI-joints, osteoarthritic hip) are relatively easily crossed by sarcoma and giant cell tumor.

Successful treatment of aneurysmal bone cyst of the hip in a child by selective transcatheter arterial embolization

Aneurysmal bone cysts are rare lesions that occur more commonly in the first and second decades of life. In children, a juxtaepiphyseal location is associated with increased risk of growth plate damage, skeletal deformity, and recurrence. Different treatments have been reported for the management of aneurysmal bone cysts, including surgical excision with or without adjuvants, intralesional injection of sclerosing agents, radiation therapy, cryotherapy, systemic calcitonin therapy, and selective arterial embolization. The authors present the case of a 5-year-old girl with a large aneurysmal bone cyst at the proximal femur, complicated by a pathologic fracture; treatment with two selective transcatheter arterial embolizations was curative.