Ameloblastic Carcinoma Presenting Clinically and Histologically as Plexiform Ameloblastoma – a Rare and Interesting Case Report and Review

Ameloblastic carcinoma is an extremely rare, aggressive malignant epithelial odontogenic tumor with characteristic histologic features and behaviour that dictates a more aggressive surgical approach than that of ameloblastoma. However, reliable evidence of its biologic activity is currently unavailable and our understanding of the histologic features of ameloblastic carcinoma is somewhat vague due to the scarcity of well-documented cases. Because the lesion is usually found unexpectedly after an incisional biopsy or the removal of a cyst, a guide to differential diagnosis is not usually useful. The identifying features of ameloblastic carcinoma must be known and recognized by dental practitioners. Wide local excision is the treatment of choice with selective regional lymph node dissection with close post operative periodic follow up. There are no definitive recommendations regarding radiotherapy and chemotherapy reported in literature. This article discusses a case of ameloblastic carcinoma which presented clinically and histologically as plexiform ameloblastoma. INTRODUCTION In 1983, Shafer introduced the term ameloblastic carcinoma to describe ameloblastomas in which there had been histologic malignant transformation. Ameloblastic carcinoma is an extremely rare, aggressive malignant epithelial odontogenic tumor with characteristic histologic features and behaviour that dictates a more aggressive surgical approach than that of ameloblastoma. However, reliable evidence of its biologic activity is currently unavailable and our understanding of the histologic features of ameloblastic carcinoma is somewhat vague due to the scarcity of well-documented cases. It is seen to occur primarily in the posterior mandible in a wide range of age groups with mean age of 30.1 years and with no sex or race predilection reported (Corio et al., 1987). The most common sign described has been swelling, although others include associated pain, rapid growth, trismus and dysphonia. Involvement of the maxilla by ameloblastic carcinoma seems to be less frequent than that of the mandible (Slootweg and Muller, 1984; Lee et al., 1990; McClatchey et al., 1989; Andersen and Bang, 1986; Daramola et al., 1980). It may present as a cystic lesion with benign clinical features or as a large tissue mass with ulceration, significant bone resorption and mobility of teeth. Because the lesion is usually found unexpectedly after an incisional biopsy or the removal of a cyst, a guide to differential diagnosis is not usually useful. The identifying features of ameloblastic carcinoma must be known and recognized by dental practitioners. The tumour cells resemble the cells seen in ameloblastoma, but they show cytologic atypia, lacking the characteristic arrangement seen in ameloblastoma. The clinical course of ameloblastic carcinoma is typically aggressive, with extensive local destruction, lymph node involvement and metastasis to various sites. Wide local excision is the treatment of choice with selective regional lymph node dissection (Dhir et al., 2003) with close post operative periodic follow up. There are no definitive recommendations regarding radiotherapy and chemotherapy reported in literature. This article discusses a case of ameloblastic carcinoma which presented clinically and histologically as plexiform ameloblastoma. CASES A 40 year old female patient reported to our centre with a complaint of painless swelling in the lower left part of face causing asymmetry and associated with numbness of lower lip since six months (figure 1). Indian Journal of Medical Case Reports ISSN: 2319–3832(Online) An Online International Journal Available at http://www.cibtech.org/jcr.htm 2013 Vol.2 (3) July-September, pp.60-63/Reddy et al.