A 14 year old boy presents with a 6 month history of a painless palpable mass on his chest wall. An MRI is shown below. The best next step in management is

 

 

 

 

[size=20px]a primary excision of the lesion

 

b arterial embolization

 

c percutaneous sclerotherapy with polidocanol

 

d systemic treatment with denosumab

 

e local curettage with autologous bone grafting[/size]

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Correct answer

A primary excision of the lesion

 

Pediatric rib lesions can be either benign or malignant with multiple etiologies. This lesion is most consistent radiographically with an aneurysmal bone cyst (ABC) with findings of an expansile rib lesion with multiple loculations and fluid/fluid levels. Aneurysmal bone cysts can be associated with other benign bone tumors (giant cell tumors, chondroblastoma) and occasionally with malignant bone tumors in particular telangiectatic osteosarcomas. The gold standard for diagnosis of pediatric rib lesions is MRI combined with biopsy. However, lesions that are most likely to be benign can proceed to primary exicision. Potential malignant lesions should proceed with needle biopsy first due to the need for neoadjuvant therapy. This particular lesion had no solid component and was not amenable to needle biopsy and a complete resection was performed.

 

Treatment choice of ABCs is dependent on the location, size, weight bearing, and possibility of pathologic fracture. For those lesions in a location that is non weight bearing or essential, i.e., the chest wall, primary complete resection can be potentially curative, although recurrence is still a possibility.

 

Selective arterial embolization as a primary treatment has been described for cases in difficult to reach locations such as the pubic bone, sacrum and spine or as a preoperative adjunct. Sclerotherapy with several different agents as been described. Polidocanol has been found to have a 83% healing rate and 75% 5-year recurrence-free rate. Sclerotherapy may require multiple injections and has been found to have similar outcomes to curettage with bone grafting but with less complications, better functional scores, and lower costs. Denosumab is a monoclonal anti-RANK-L antibody used to treat bone loss due to increased osteoclast activity. Denosumab is effective rescue therapy for controlling ABCs and is used primarily for unresectable lesions. Curettage with bone grafting is used for weight bearing bones.