Osteoid Osteoma with a Multicentric Nidus: Interstitial Laser Ablation under MRI Guidance

Atypical Presentation of an Osteoid Osteoma With a Multicentric Nidus

An osteoid osteoma is typically a benign bone tumor affecting young adult males, often presenting with nocturnal pain alleviated by nonsteroidal anti-inflammatory medications (NSAIDS). It usually manifests as a solitary nidus with surrounding sclerosis. An osteoid osteoma with a multicentric nidus, characterized by multiple nidi, is a rare variant. A 12-year-old girl presented with a one-year history of worsening, nighttime pain in her upper left leg. Plain radiographs revealed two lytic lesions with sclerosis. A computed tomography (CT) scan confirmed two well-defined sclerotic lesions with central lytic lesions. Magnetic resonance imaging (MRI) demonstrated two hypointense lesions with peripheral hyperintensity on short tau inversion recovery (STIR) sequences, suggestive of osteoid osteoma with a multicentric nidus. Differential diagnoses included osteomyelitis with Brodie's abscess, osteoblastoma, chondroblastoma, and malignant lesions. Due to the atypical presentation and lack of experience with radiofrequency ablation (RFA) for multicentric cases, surgical excision was performed. Histopathology confirmed osteoid osteoma. After rehabilitation, the patient was asymptomatic at six months with no recurrence on radiographs. This case highlights the unusual presentation of osteoid osteoma with a multicentric nidus in a young female. Radiological workup with plain films, CT, and MRI was crucial for diagnosis. While RFA is gaining popularity, surgical excision remains a valid option, especially for atypical cases.

Computed tomography guided radiofrequency ablation of osteoid osteoma in children: a single center's experience

OBJECTIVE

To report a single center's experience evaluating the efficacy and safety of computed tomography-guided radiofrequency ablation for the treatment of osteoid osteoma in children.

MATERIALS AND METHODS

Institutional database research identified 33 symptomatic patients (≤ 18 years of age; male/female ratio: 21/12, mean age 13.09 ± 3.66) with osteoid osteoma who were treated by CT-guided RFA. Technical and clinical success as well as complication rates were recorded. The duration of the procedure, the number of computed tomography scans and the results of the biopsy were assessed. Pain, prior, the following morning and 1 week, 1/6/12 months after the procedure were compared by means of a numeric visual scale (NVS) questionnaire.

RESULTS

Mean lesion size was 8.28 ± 4.24 mm. Mean follow-up was 23.33 ± 17.61 months (range 12-62). Mean pain score prior to radiofrequency ablation was 9.06 ± 0.80 NVS units. On week 1 and 1/6/12 months, all patients were pain-free reporting 0 NVS units (p < 0.05). The mean procedure time was 54 min (range 51-59) and a mean of 7 CT scans were performed during the ablation session. RF electrode was successfully placed in the center of the nidus in all cases. In our study, none of our patient experienced recurrence of the pain, nor complications.

CONCLUSION

The present study demonstrates that percutaneous CT-guided radiofrequency ablation constitutes a safe and effective technique for osteoid osteoma treatment in children.

Osteoid osteoma: the great mimicker

Osteoid osteoma is a painful, benign and common bone tumor that is prevalent in young adults. The typical clinical presentation consists of pain that becomes worse at night and is relieved by nonsteroidal anti-inflammatory drugs. The most common imaging finding is a lytic lesion, known as a nidus, with variable intralesional mineralization, accompanied by bone sclerosis, cortical thickening and surrounding bone marrow edema, as well as marked enhancement with intravenous contrast injection. When the lesion is located in typical locations (intracortical bone and the diaphyses of long bones), both characteristic clinical and radiological features are diagnostic. However, osteoid osteoma is a multifaceted pathology that can have unusual presentations, such as intraarticular osteoid osteoma, epiphyseal location, lesions at the extremities and multicentric nidi, and frequently present atypical clinical and radiological manifestations. In addition, many conditions may mimic osteoid osteoma and vice versa, leading to misdiagnosis. Therefore, it is essential to understand these musculoskeletal diseases and their imaging findings to increase diagnostic accuracy, enable early treatment and prevent poor prognosis.

Evaluation of minimally invasive laser ablation in children with osteoid osteoma

The effects between minimally invasive percutaneous laser ablation and open surgery in the treatment of children with osteoid osteoma were compared in the present study. A total of 72 cases of children with osteoid osteoma were divided into control and observational groups, containing 36 cases in each group. The control group underwent conventional open surgery while the observational group underwent minimally invasive CT guided percutaneous laser ablation. Effects of both operations were compared. The operation duration, blood loss and plaster fixation duration of the observational group were significantly less than those of the control group. The postoperative pain score (VAS) at 1 day and 7 days were significantly lower than that of the control group, the differences were statistically significant (P<0.05). The lesion resection rate, effective rate of bone hyperplasia, effective rate of swelling and effusion and total effective rate of the observational group were significantly higher than those of the control group, the differences were statistically significant (P<0.05). Incidence of adverse reactions of observational group was significantly lower (P<0.05) than that of the control group. However, the difference was not significant when comparing 1-year recurrence rate for the two groups. The minimally invasive percutaneous laser ablation has better surgery effects compared with open surgery in the treatment of children with osteoid osteoma.