A popliteal giant synovial osteochondroma mimicking a parosteal osteosarcoma

The Epidemiology of Benign Proliferative Processes of the Skeletal System in Children

A suspicion of a proliferative bone lesion in a child seems to be a major diagnostic problem for clinicians. There are no diagnostic and treatment algorithms described in the literature and no reliable cohort epidemiological data. Our study was conducted among 289 paediatric patients (0–18 years old) with an initial diagnosis of a bone tumour or tumour-like lesion. The study comprised a retrospective epidemiological analysis, an assessment of the concordance of the initial diagnoses with the histopathological diagnoses and an analysis of the specific locations of the various bone lesions. The results obtained have made it possible to formulate the following conclusions. (1) The most common proliferative bone lesion in children is osteochondroma; also common are fibrous dysplasia, non-ossifying fibromas and bone cysts. (2) Verifying the initial diagnosis by means of biopsy is essential. (3) Osteochondromas are typically located in the metaphyses of long bones, fibrous dysplasia in the femur and skull, cyst-like lesions in the proximal humerus and non-osteochondral fibromas exclusively in the lower limbs. What could improve the quality of treatment for children with primary proliferative bone diseases is the establishment of centres of paediatric orthopaedic oncology skilled in early diagnosis and prompt management.

Case Report: Unusual Presentation of Myositis Ossificans of the Elbow in a Child Who Underwent Excessive Postoperative Rehabilitation Exercise

Traumatic myositis ossificans (MO) is an unusual complication after muscle injury and is predominantly seen in young adults and adolescents. Pediatric MO cases are even rarer. We report an 8-year-old girl who was diagnosed with a lateral humeral condyle fracture. She was treated surgically, and her elbow joint was fixed with plaster. Rehabilitation exercise was administered 1 month after the operation. Due to the wrong exercise method, a palpable bony mass appeared around the elbow 1 month later. The clinical radiological diagnosis showed MO, and conservative treatment was administered. After 3 years of follow-up, the affected limb functioned well, with no sign of recurrence. Here, we report this long-term follow-up case of MO resulting from excessive rehabilitation exercise.

Parosteal Osteosarcoma of the Distal Radius Mimicking an Osteochondroma-A Diagnostic Misadventure

We present a case of a parosteal osteosarcoma mimicking an osteochondroma with atypical clinical features, radiographic findings, and histological examination. This report serves to exemplify the importance of recognizing the similarities between these 2 entities and other peculiar features that will help to differentiate between sessile osteochondromas and parosteal osteosarcomas, to prevent misdiagnosis.

An Unusual Presentation of Myositis Ossificans in a Pediatric Patient

BACKGROUND

Myositis ossificans (MO) is a rare, non-neoplastic lesion characterized by heterotopic ossification of soft tissue. The condition is predominantly seen in young adults and adolescents and is most commonly secondary to trauma. Although the exact etiology remains unclear, patients typically present with pain and restricted range of motion following trauma or overuse. MO rarely presents in the popliteal fossa of adult patients and has not been previously reported in that of a pediatric patient.

METHODS

We present a 12-year-old patient with no history of direct trauma with MO in the right popliteal fossa, a highly unusual location. Initial x-rays failed to show the lesion; however, later radiographs showed an ossified mass. At peak dimensions, the ossification measured 3.8 cm anteroposterior×2.5 cm transverse×3.2 cm craniocaudal. After 14 months of observation and conservative therapy, the mass was excised.

RESULTS

The patient was ultimately able to return to full activity. Radiographs taken 14 months after the excision showed no signs of recurrence of the lesion.

CONCLUSIONS

To our knowledge, this is the first reported case of MO excised from the popliteal fossa of a pediatric patient and followed for >1 year.

LEVEL OF EVIDENCE

Level IV-case report.