Year : 2008 | Volume
: 25 | Issue : 2 | Page : 62--64
Cytological diagnosis of acanthomatous ameloblastoma
Vaishali A Walke, Maitreyee M Munshi, Wamanrao K Raut, Sudhakar K Bobahate
Department of Pathology, Govt. Medical College, Nagpur, Maharashtra, India
Vaishali A Walke
20-A, Swami Samarth Apartment, Wanjari Nagar, Nagpur - 440 003, Maharashtra
Ameloblastomas show wide morphological spectra and may pose diagnostic difficulties. Of the many types encountered, acanthomatous ameloblastoma is a rare variant that possesses distinctive features. To the best of our knowledge, there have been no previous reports on the cytology of acanthomatous ameloblastoma (AA). An elderly male presented with a radiolucent jaw swelling. Cytology smears showed combinations of basaloid cells with peripheral palisading, stellate cells as well as squamous cells in groups and in isolation. A diagnosis of acanthomatous ameloblastoma was made and subsequently confirmed on histology. Although AA is a rare jaw tumor, it possesses distinctive cytological features that permit confident preoperative cytodiagnosis.
|How to cite this article:|
Walke VA, Munshi MM, Raut WK, Bobahate SK. Cytological diagnosis of acanthomatous ameloblastoma.J Cytol 2008;25:62-64
|How to cite this URL:|
Walke VA, Munshi MM, Raut WK, Bobahate SK. Cytological diagnosis of acanthomatous ameloblastoma. J Cytol [serial online] 2008 [cited 2019 Sep 19 ];25:62-64
Available from: http://www.jcytol.org/text.asp?2008/25/2/62/42447
Ameloblastoma is a rare odontogenic jaw tumor that is a challenge to pathologists because of its diversity of histological features and to surgeons due to its frequent defiance to complete eradication. 
Whereas histopathological and radiological findings for ameloblastomas have been extensively studied, fine needle aspiration cytology (FNAC) reports are rare. , We discuss here a case of acanthomatous ameloblastoma of the mandible diagnosed on FNAC and its differential diagnoses.
A 50 year-old male was referred to the Cytology outpatient department with a progressively increasing mass over the right mandibular region over the last six months. It was 10 x 6 cm in size, well-defined, fixed, hard, and nontender. Radiographs revealed a destructive, well-defined, radiolucent lesion of the right ramus of the mandible. FNAC was tried with multiple passes. Smears were wet-fixed and stained by using the Papanicolaou (Pap) and hematoxylin and eosin (H and E) stains, while air-dried smears were stained with May-Grünwald-Giemsa (MGG).
Cytology: FNAC smears were cellular and showed microbiopsies, cohesive sheets, and solid nests with peripheral palisading [Figure 1]. Cells in solid nests and groups were uniform with scanty basophilic cytoplasm. The nucleus was central, round, and hyperchromatic with dense chromatin. Foci of loosely arranged, spindle-shaped cells with ovoid nuclei were also seen [Figure 2]. Squamous cells were seen in groups and as isolated cells. They were polygonal to round with abundant dense eosinophilic cytoplasm and central pyknotic nuclei [Figure 3].
Histology: Histopathology revealed solid epithelial cell nests with peripheral palisading and central stellate reticulum. A few cell nests also showed squamous differentiation with well-formed pearls [Figure 4]. Focal cystic changes were also seen.
Ameloblastomas account for 1% of all tumors of the jaw encountered during the 3 rd to 5 th decades of life. About 80% of all cases occur in the mandible, of which 70% cases are seen in the ramus. Various morphological subtypes have been described, including those of follicular, plexiform, acanthomatous, granular, and basal cells.  As with all other bone tumors, the diagnosis of ameloblastoma should be made only in appropriate clinical and radiological settings. 
In spite of the ease of aspiration due to the lysis of the bone, it has been observed that these lesions are rarely being aspirated. , One explanation may be that cytologists have limited experience with these lesions, making their interpretation difficult. 
The characteristic cytological triad, in the form of cohesive sheets of basaloid cells with peripheral palisading, loosely arranged spindle-shaped cells along with groups and clusters of squamous cells, provide the basis for not only the correct diagnosis but also to the exclusion of look-alikes. ,,
In both benign cystic lesions of the jaw and cystic ameloblastomas, the background of polymorphs, foamy macrophages, and amorphous proteinaceous material may pose diagnostic difficulty. ,, Of benign cystic lesions of the jaw, follicular cysts yield straw-colored fluid containing a few squamous cells along with foamy macrophages.  Odontogenic keratocysts show many anucleate and nucleate squamous cells having central pyknotic nuclei among keratinous debris.  Epidermal inclusion cysts show similar cytomorphology but are usually located subcutaneously.  The trimodal populations of basaloid, stellate and squamous cells help to differentiate ameloblastomas from these benign cystic lesions of the jaw.
Mucoepidermoid carcinomas are also differential diagnoses which show an admixture of mucin-secreting, columnar cells (better seen when stained with MGG) and intermediate and squamoid cells in a dirty background of mucus and debris. There are no accompanying basaloid and stellate cells. ,
Osteolytic bony lesions due to metastasis of squamous cell carcinomas to the jaw can also be one of the differentials, particularly when the squamous component of AA looks atypical. Diligent search for basaloid cells and stellate reticulum can avoid a misdiagnosis.
In conclusion, in the presence of correct clinico-radiologic inputs, preoperative cytological diagnosis of ameloblastomas can be rendered with reasonable accuracy with the aid of FNAC. ,,
|1||Matheus S, Rappaport K, Ali SZ, Busceniers AE. Ameloblastoma, cytologic findings and literature review. Acta Cytol 1997;41:955-60.|
|2||Deshpande A, Umap P, Munshi M. Granular cell ameloblastoma of jaw: A report of two cases with FNAC. Acta Cytol 1999;43:1-5.|
|3||Rekhi B, Saxena S. Cytomorphology of basal cell type of solid ameloblastoma: A case report. J Cytol 2006;23:83-5.|
|4||Ramzi I, Aufdemorte TB, Duccan DL. Diagnosis of radiolucent lesions of jaw by fine needle aspiration biopsy. Acta Cytol 1985;29:419-24.|
|5||Stamtakos MD, Houston GD, Fowler CB, Boyd E, Solanki PH. Diagnosis of ameloblastoma of the maxilla by fine needle aspiration. Acta Cytol 1995;39:817-20.|
|6||Ramzi I, Rone R, Schantz D. Squamous cells in needle aspirates of subcutaneous lesions. A diagnostic problem. Am J Clin Pathol 1986;35:319-24.|