Serially recurrent osteoid osteoma

Elongated morphology of osteoid osteoma is associated with radiofrequency ablation failure in children

OBJECTIVE

To compare the frequency of elongated morphology of osteoid osteoma (OO) in children compared to adolescents and to determine if this elongated morphology is associated with radiofrequency ablation treatment failure.

MATERIALS AND METHODS

Retrospective review of first-time CT-guided radiofrequency ablation performed for presumed OO in patients < 21 years old between 1990 and 2023. Children were considered 0 to 10 years old, and adolescents were considered 11 to 20 years old. Treatment failure was considered symptomatic recurrence requiring follow-up intervention. The largest tumor dimensions in three orthogonal planes were measured using multiplanar reformatted technology. Maximum tumor dimension, tumor volume, and eccentricity index were calculated. Elongated morphology criteria were (a) largest dimension > 10 mm and (b) eccentricity index ≥ 3. Lesion locations were recorded. Statistical analyses included the chi-square test, Fisher's exact test, nonparametric Wilcoxon rank-sum test, receiver operating characteristic analysis, and Spearman's nonparametric rank correlation.

RESULTS

Of 366 included patients (median 15 years, IQR 11-18 years, 254 male), there were 86 (23.5%) children, 280 (76.5%) adolescents, and 24 (6.6%) cases of treatment failure. Elongated morphology was more common in children (19.7%) than adolescents (8.6%) (p = 0.004) and associated with younger age (p = 0.009). Elongated morphology was associated with treatment failure in children (p = 0.045) but not adolescents (p > .99) or all patients (p = 0.17). Treatment failure was not associated with age, largest dimension, eccentricity index, volume, or location.

CONCLUSION

Elongated morphology of OO is associated with younger age and radiofrequency ablation treatment failure in children. Identifying this morphology may assist with counseling and treatment planning.

Recurred forehead osteoma disseminated after previous osteoma excision: A case report

BACKGROUND

Forehead osteoma is a commonly encountered benign facial bone tumor. Endoscopic excision of benign forehead masses is widely performed. Here, we report a rare case of recurrent forehead osteoma that disseminated after a previous osteoma excision.

CASE SUMMARY

A 54-year-old female patient had previously undergone endoscopic removal of a single forehead osteoma at 30 years of age. However, she had a recurrent osteoma around the same site and underwent another endoscopic resection at 40 years of age. During her first visit to our outpatient clinic, she presented with a cobblestone-like irregular surface on the forehead and a 3D facial bone computed tomography scan revealed a widely ragged surface of the inoculated osteoma on the outer table of the frontal bone. Under general anesthesia, we performed a radical complete excision of the disseminated osteoma through a bicoronal incision using an osteotome, chisel, mallet, and rasping. We hypothesized that the recurrence may have been caused by the inoculation of residual osteoma remnants from the previous procedure. Craniofacial surgeons should be cautious when removing osteoma particles, particularly when using an endoscopic approach.

CONCLUSION

To prevent recurrence, it is essential to conduct additional meticulous burring and a thorough inspection of the surface after copious irrigation.

Computed tomography guided radiofrequency ablation of multifocal osteoid osteoma

Osteoid osteoma is a benign osteoblastic tumor characterized mostly by presence of one nidus, butvery infrequentlyniduses can be multiple. Radiofrequency ablation is a well-established treatment method for this disease. We report a case of a 19-year-old male patient with bifocal osteoid osteoma which was partially missed on the initial magnetic resonance imaging and treated successfully with two sessions of radiofrequency ablation. Following the second session of ablation, the pain resolved immediately and the patient remains pain-free for 6 months since the procedure. Our case report underlines the fact that although very rare, multifocal osteoid osteomas do exist and its niduses can be obscured during the magnetic resonance imaging due to the edema. It emphasizes the role of the initial computed tomography evaluation.

Multicentric, multifocal, and recurrent osteoid osteoma of the hip: first case report

BACKGROUND

Osteoid osteoma is a benign bone-forming tumour, which very unfrequently has multifocal or multicentric presentation. We report the first known case of a multicentric, multifocal and recurrent osteoid osteoma treated using radiofrequency ablation.

CASE PRESENTATION

A 39-year-old man with two-year history of left hip pain was admitted at our Institution. The pain was more intense during the night and partially relieved by salicylates. Pelvis CT demonstrated two lytic lesions (8 and 7 mm, respectively) with surrounding sclerotic reactive bone, both with a central focal area of high attenuation, located in the femoral neck and along the anterior portion of the acetabulum, respectively. Both lesions had clinical and imaging findings consistent with multicentric osteoid osteoma. Thus, the two lesions were biopsied - with pathologic confirmation of osteoid osteoma - and treated using radiofrequency ablation. Hip pain decreased but did not disappear, actually increasing a few months after treatment. CT and MRI were performed showing a smaller lesion (5 mm) with the same imaging features, surrounded by marrow oedema, along the posterior column of the acetabulum. The lesion was considered suspicious for osteoid osteoma, overlooked on previous examinations. Therefore, a diagnosis of multicentric and multifocal osteoid osteoma was established. The new lesion was again treated with radiofrequency ablation with symptom disappearance. However, hip pain relapsed after 18 months, and CT and MRI showed an osteoid osteoma recurrence on the posterior column of the acetabulum, which was biopsied and successfully treated using radiofrequency ablation.

CONCLUSIONS

To our knowledge, this is the first reported case of multicentric, multifocal, recurrent osteoid osteoma. Our case report highlights the importance of considering a diagnosis of multifocal osteoid osteoma when dealing with multifocal lytic lesions of the bone and with pain persistence after treatment. It also emphasises the combined role of CT and MRI in this setting.

Diffusion weighted MRI of osteoid osteomas: Higher ADC values after radiofrequency ablation

PURPOSE

Feasibility of diffusion weighted MRI (DWI) pre- and post-radiofrequency ablation (RFA) in patients with osteoid osteoma (OO).

MATERIAL AND METHODS

Ten patients (1 female, 24±9years) received RFA of OO (mean size 8.7±3.2mm). Two OO recurred, in one of these a second RFA was performed. A 1.5T DWI (b=50, 400, and 800s/mm(2)) and a fat saturated DCE MRI were obtained the day before and after RFA. In DWI, the mean apparent diffusion coefficient (ADC) was recorded. With DCE MRI, signal-to-noise ratio, contrast-to-noise ratio, absolute signal intensity (SI), relative SI, and SI ratio were documented. All parameters were compared pre- and post-RFA using paired Wilcoxon rank test.

RESULTS

ADC values were significantly higher post-ablation, 1.6±0.5μm(2)/ms versus 1.3±0.6μm(2)/ms (p<0.05). Perfusion was significantly reduced after ablation [SNR, CNR, SI, %SI, and SI OO/SI muscle]; post-RFA: 55±13, 27±20, 757±534, 102±16, and 1.6±0.2; pre-RFA: 88±37, 65±22, 1038±755, 226±51, and 2.0±0.5 (p<0.05).

DISCUSSION

DWI is feasible in OO. ADC values increased and contrast enhancement decreased after RFA of OO. This may be explained by RFA-induced necrosis and devascularization.

Treatment of Osteoid Osteomas Using a Navigational Bipolar Radiofrequency Ablation System

BACKGROUND

Percutaneous CT-guided radiofrequency ablation is a safe and effective minimally invasive treatment for osteoid osteomas. This technical case series describes the use of a recently introduced ablation system with a probe that can be curved in multiple directions, embedded thermocouples for real-time monitoring of the ablation volume, and a bipolar design that obviates the need for a grounding pad.

METHODS

Medical records of all patients who underwent radiofrequency ablation of an osteoid osteoma with the STAR Tumor Ablation System (DFINE; San Jose, CA) were reviewed. The location of each osteoid osteoma, nidus volume, and procedural details were recorded. Treatment efficacy and long-term complications were assessed at clinical follow-up.

RESULTS

During the study period, 18 osteoid osteomas were radiofrequency ablated with the multidirectional bipolar system. Lesion locations included the femur (50%; 9/18), tibia (22%; 4/18), cervical spine (11%; 2/18), calcaneus (5.5%; 1/18), iliac bone (5.5%; 1/18), and fibula (5.5%; 1/18). The median nidus volume of these cases was 0.33 mL (range 0.12-2.0 mL). All tumors were accessed via a single osseous channel. Median cumulative ablation time was 5 min and 0 s (range 1 min and 32 s-8 min and 50 s). All patients with clinical follow-up reported complete symptom resolution. No complications occurred.

CONCLUSION

Safe and effective CT-guided radiofrequency ablation of osteoid osteomas can be performed in a variety of locations using a multidirectional bipolar system.