Secondary jaw aneurysmal bone cyst (JABC)--a possible misnomer? A review of literature on secondary JABCs, their pathogenesis and oncogenesis.

CONTEXT: Aneurysmal bone cysts are rare pseudocysts, commonly seen in long bones and vertebral column. Although a well described and reported lesion, many misconceptions still prevail regarding their etiopathogenesis. Many of the reported cases of jaw aneurysmal bone cysts (JABC) present with another bone pathology.

AIMS: The purpose of this review was to evaluate the incidence of neoplastic lesions occurring simultaneously with a JABC (in contrast to primary JABCs). Any pathogenetic and oncogenetic association between primary and secondary jaw ABCs has been reviewed and discussed.

SETTINGS AND DESIGN: A methodical narrative review of literature was performed, given the incidence of mostly case reports on this topic.

METHODS AND MATERIAL: A methodical electronic search of Pubmed, Pubmed Central, Medline and Cochrane databases was performed for reported cases of JABC. These articles were analysed and segregated into primary and secondary ABC and, if secondary, the lesion it concurrently occurred with. Another search was conducted to yield articles discussing the cytopathogenetic and oncogenetic origins of ABCs.

RESULTS AND CONCLUSIONS: About 15% of the ABCs reported were of secondary nature. Amongst the associated lesions, cement-ossifying fibroma and ossifying fibroma were the most common, followed by fibrous dysplasia and central giant cell granuloma. No ABCs were associated with metastatic changes. The search for histopathogenesis pointed to a specific cytogenetic abnormality as the origin of primary ABCs, with USP6 as its main oncogene and spindle cell as the neoplastic cell, unlike with secondary ABCs, suggesting that they are distinct pathological processes.