Role of FNAC in the diagnosis of intraosseous jaw lesions

Abstract

Background: FNAC of intraosseous jaw lesions has not been widely utilized for diagnosis due to rarity and diversity of these lesions, limited experience and lack of well established cytological features. Aim of the study was to determine the role of FNAC in the diagnosis of intraosseous jaw swellings.

Material and methods: 42 patients underwent FNAC over a period of 7 years (2007-2013), of which 37 (88.1%) aspirates were diagnostic. Histopathology correlation was available in 33 cases and diagnostic accuracy of FNAC was calculated.

Results: Lesions were categorized into inflammatory 3, cysts/hamartomas 15 and neoplasms 19. Mandibular and maxillary involvement was seen in 21 and 16 patients respectively. Of these, benign cysts and malignant lesions were commonest, accounting for 27% lesions (10 cases) each. One case of cystic ameloblastoma was misdiagnosed as odontogenic cyst on cytology. Overall, sensitivity and specificity of FNAC were 94.7% and 100% respectively with a diagnostic accuracy of 97.3%. Definitive categorization of giant cell lesions, fibro-osseous lesions, odontogenic tumors and cystic lesions was not feasible on FNAC.

Conclusions: FNAC is a simple, safe and minimally invasive first line investigation which can render an accurate preoperative diagnosis of intraosseous jaw lesions, especially the malignant ones in the light of clinic-radiological correlation.

Figure 1

Orthopantomogram shows a well defined expansile lytic lesion in relation to roots of canines in mandible. b) Aspirate smear shows numerous anucleate squames suggestive of odontogenic cyst.

Figure 2

Aspirate smear from an ulcerated growth on gingiva shows numerous multinucleated giant cells and histiocytes adhered to fragments of fibrovascular stroma, suggestive of a giant cell lesion with the possibility of central giant cell granuloma (Pap x 400).

Figure 3

a) Orthopantomogram shows a large well-defined expansile lytic lesion involving the body of mandible, in bilateral paramidline regions. No cortical breech / periosteal reaction / tooth displacement / root resorption seen. b) Aspirate shows cohesive cluster of basaloid epithelial cells with peripheral palisading and polygonal squamous cells with dense inky blue cytoplasm (Inset) in a proteinaceous background, suggestive of ameloblastoma (MGG x 100). c) Histopathology confirms the squamous differentiation within the basaloid clusters (H&E x200).

Figure 4

Aspirate from a case of eosinophilic granuloma involving mandible shows numerous histiocytes, eosinophils and neutrophils (MGG x400). Inset shows characteristic rhomboid blue Charcot Leyden crystals and Langerhans cell histiocytes with longitudinal nuclear grooves.

Figure 5

a) Aspirate smear from a mixed radiolucent lesion in maxilla shows presence of numerous plump fibroblastic cells and occasional osteoblast, suggestive of fibrosseous lesion (MGG x400). b) Histopathology shows predominantly fibroblastic stroma and irregular deposits of pink hyaline cementum like material with central calcification, confirming the diagnosis of cemento-ossifying fibroma (Hematoxylin & Eosin x100).

Figure 6

a) Aspirate smear shows plasmacytoid osteoblasts having moderate amount of cytoplasm with round nuclei, fine chromatin and distinct, single nucleolus. Few benign appearing osteoclastic giant cells and occasional binucleated cells are also seen (Pap x400). b) Histopathology confirms a bone forming tumor comprising osteoid surrounded by rim of epithelioid osteoblasts. Intervening loose fibrovascular stroma has scattered osteoclasts (H&E x200).

Figure 7

Photograph of a 55 year old patient presenting with right cheek mass. b) Aspirate smear shows features of Non Hodgkin lymphoma (MGGx 200) c) On immunocytochemistry, tumor cells were strongly CD20 positive (Immunostain x 200).