Squamous odontogenic tumor-like proliferations in radicular cysts: a clinicopathologic study of forty-two cases

Squamous odontogenic tumor-like epithelial islands occurring in the walls of odontogenic cysts are histologically identical to the squamous odontogenic tumor (SOT). Microscopically, the squamous odontogenic tumor-like proliferations (SOTLPs) share certain histologic features with SOT, acanthomatous and desmoplastic ameloblastoma, and well-differentiated squamous cell carcinoma. Little is known about the rarely reported SOTLPs occurring in radicular cysts. The purpose of this study was to define the clinical and histopathologic spectrum of SOTLP in radicular cysts and to investigate its histogenesis, prevalence, and biologic behavior.

A retrospective clinicopathologic study was conducted at the Louisiana State University School of Dentistry, and a total of 42 radicular cysts with SOTLPs were accepted. Clinical findings and detailed histopathologic features were documented, and follow-up information was solicited for the 42 cases.

Forty-two cases of radicular cysts with SOTLPs were found among 1241 radicular cysts. Two thirds of the cases revealed the SOTLPs were arising from budlike extensions of the epithelial lining of the cyst. The SOT-like epithelial islands were in areas free of inflammatory cells in 73.8% of the cases. No evidence of recurrence or unexpected clinical behavior was reported in 11 cases with adequate follow-up.

The prevalence of SOTLPs in radicular cysts at Louisiana State University School of Dentistry is 3.4%. The SOTLPs appear to originate from the epithelial lining of the cyst and do not appear to be directly associated with inflammation. The biologic behavior of the radicular cyst with SOTLP is innocuous, with no apparent potential for neoplastic transformation or recurrence.