Ameloblastoma. Cytologic findings and literature review

To define and elaborate the cytomorphologic features of primary and metastatic ameloblastoma (ABL) on fine needle aspiration (FNA) and to discuss the differential diagnosis with closely related entities and review the cytologic literature on the subject.

A retrospective study consisting of five cases of ameloblastomas, primary in the mandible (n = 3) and metastases (n = 2), diagnosed by FNA cytology with appropriate cytohistologic correlation, was done. Smears were stained with the Diff-Quik and Papanicolaou methods. Hematoxylin and eosin-stained sections of paraffin block as well as sections from the surgically resected specimens were also reviewed.

The smears were hypercellular and occasionally showed tissue fragments of basaloid cells with peripheral palisading. A distinct, two-cell population was seen, consisting of small, hyperchromatic, basaloid-type cells and scattered larger cells with more open chromatin. Occasional fragments of mesenchymal cells with more elongated nuclei and ample, clear cytoplasm were also noted. Malignant cases that metastasized showed prominent cytologic pleomorphism, cellular crowding with molding and a high mitotic/karyorrhectic index.

In the right clinical setting and with proper radiologic evidence, the cytologic features of primary and metastatic ameloblastoma are unique. Diagnostic problems may arise when these lesions are pleomorphic and frankly malignant, especially at metastatic sites, such as the lung. FNA, therefore, is a valuable diagnostic tool in the initial diagnosis and follow-up of patients with a history of ameloblastoma.