Sclerosing odontogenic carcinoma: a rare and challenging biopsy diagnosis

Abstract

<h3>Introduction</h3> Sclerosing odontogenic carcinoma (SOC) is a primary intraosseous malignancy first described by Koutlas et al. in 2008 and recently listed as a separate entity in the 2017 World Health Organization Classification of Head and Neck Tumors. Fewer than fifteen cases of SOC have been reported in the literature to date, with many mischaracterized on initial biopsy diagnosis. This mischaracterization, particularly on biopsy, is likely attributable to the subtle and variable histologic features of SOC. We present a case of SOC and review the literature with emphasis on clinical and histologic features that should raise suspicion for this lesion on biopsy. <h3>Material and Methods</h3> The biopsy specimen was submitted in a 10% formalin fixative and subsequently embedded in paraffin. The specimen was processed into four-micrometer-thick sections and stained for routine microscopic examination. Immunohistochemical studies were performed and included antibodies against CK5/6, CK19, e-cadherin, CK7, CK20, p63, and Ki67. <h3>Results</h3> A review of the literature demonstrated only one set of authors reporting an initial biopsy diagnosis of SOC. The remainder of reported cases required a minimum of one repeat biopsy, and in several cases, diagnosis was only established following complete excision. Therapeutic approaches ranged from conservative marginal excision to radical excision with neck dissection and adjuvant chemotherapy and radiation. Regardless of therapy modality all cases demonstrated no recurrence, with one exception, likely attributable to positive margin status at resection. <h3>Conclusions</h3> Given the subtle features of SOC that may often mimic other benign and malignant processes, sufficient awareness and suspicion for this entity is necessary for diagnosis, and ultimately to guide clinical management. In the absence of an established diagnosis of SOC, multiple reported patients have undergone more radical therapy than what appears to be necessary for the management of this low-grade entity with no apparent metastatic potential.