Fine-Needle Aspiration Biopsy as an Initial Diagnostic Modality in a Clinically Unsuspected Case of Invasive Maxillary Fungal Sinusitis: A Case Report Neha Singh, M.B.B.S., Neelaiah Siddaraju, M.D., * Surendra Kumar, M.D., Femela Muniraj, M.B.B.S., Satvinder Bakshi, M.B.B.S., and Suryanarayanan Gopalakrishnan, M.S. Cases of invasive fungal lesions involving the paranasal sinuses are generally diagnosed either on histologic examination or on fungal culture. Here, we report a case of invasive fungal sinusi- tis diagnosed primarily by a fine-needle aspiration biopsy (FNAB). Our patient was a 36-year-old male who presented with a his- tory of slowly progressive, painless swelling over the left cheek. The only positive clinical finding was a bony hard swelling in the left maxillary region, which was clinically interpreted as ‘‘fibrous dysplasia.’’ A computed tomographic (CT) examination of the paranasal sinuses showed a soft tissue attenuation lesion involving the bilateral maxillae, with the destruction of multiple bones and involvement of multiple sinuses and the bilateral orbits. FNAB of the maxillary swelling showed several giant cells, many of them exhibiting ingested organisms with a mor- phologic resemblance to the Aspergillus species of fungi. Strik- ingly, no significant inflammatory cells were seen on cytologic smears. Unfortunately, owing to a lack of initial clinical suspi- cion, as well as the patient’s loss to further follow-up, a culture/ histopathologic examination could not be carried out. This case is presented chiefly to highlight the clinical utility of a simple FNAB procedure, as an initial diagnostic modality in cases of fungal sinusitis, which can masquerade clinically as a neoplastic lesion. In addition, if radiologic findings are also available at the time of cytologic examination, a pretherapeutic comment on the invasive nature of the lesion can also be made. Diagn. Cytopathol. 2010;38:290–293. ' 2009 Wiley-Liss, Inc. Key Words: aspiration biopsy; fine needle; sinus, maxillary; fungal sinusitis, invasive; CT scan The increased incidence of fungal diseases in humans is attributed chiefly to the inappropriate use of broad spec- trum antibiotics as well as to an increasing number of immunocompromised patients. The fungal organisms known to cause lesions in the paranasal sinuses (PNS) include Aspergillus species and phacoid fungi such as Bipolaris, Exerohilum, Curvularia, and Alternaria. Of these fungi, Asperigillus is the most common. 1 Aspergil- lus is a spore forming fungus found in the soil and decay- ing vegetable matters. Generally, the spores of the fungi are introduced in to the upper respiratory tract by inhala- tion. 2 The common species causing aspergillosis of the PNS are Aspergillus fumigatus, Aspergillus niger, and Aspergillus flavus. 3 The invasive form of fugal diseases of the paranasal sinuses, such as aspergillosis can be localized or fulmi- nant. Apart from involving PNS, it can also cause an or- bital extension, resulting in the visual loss. The common predisposing conditions associated with invasive fungal diseases are HIV infection, neutropenia, prolonged corti- costeroid and immunosuppressive therapy, uncontrolled diabetes mellitus, radiation therapy, and burns and trauma. 2,4,5 Nonetheless, there also have been case reports on invasive fungal sinusitis occurring in immunocompetent individuals. 4,6,7 With a high index of clinical suspicion, a computed tomographic (CT) scan helps in the preoperative diagnosis of fungal sinusitis. However, identification of the fungal species depends on the demonstration of organisms by culture or on histologic material obtained from the Department of Pathology, Division of Cytology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India *Correspondence to: Neelaiah Siddaraju, M.D., Professor Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry 605 006, India. E-mail: rajusiddaraju@yahoo.com Received 3 May 2009; Accepted 20 August 2009 DOI 10.1002/dc.21216 Published online 5 November 2009 in Wiley InterScience (www. interscience.wiley.com). 290 Diagnostic Cytopathology, Vol 38, No 4 ' 2009 WILEY-LISS, INC.