Pitfalls in the diagnosis of lesions of sinonasal tract both on clinical and histopathological grounds

Background: The nasal cavity and paranasal sinuses are collectively referred to as the sinonasal tract, which is anatomically and embryologically distinct from the nasopharynx. Aim and objectives: To understand the variable clinical presentations of three unusual cases in the sinonasal tract, to study the histomorphology and analyze the pitfalls in their diagnosis, to study the differential diagnosis and review the literature. Materials and methods: Unusual presentations of three cases were encountered during the period from October 2016 to July 2017 in the Department of Pathology, Government ENT Hospital, Hyderabad. Excised specimens of all the three cases were received and subjected to routine processing, cutting, staining and histopathological features were analyzed. Special histochemical and immunohistochemical stains were done for confirmation of final diagnosis. Results: Case 1 was Rosai Dorfman Disease, Case 2 was Botryoid Embryonal Rhabdomyosarcoma and Case 3 was Invasive Aspergillosis. Conclusion: Rosai Dorfman Disease has to be differentiated from lymphoproliferative and other histiocytic disorders while the benign inflammatory pattern of Botryoid Embryonal Rhabdomyosarcoma is invariably mistaken for an inflammatory process. Aspergillosis mimics as a neoplastic lesion, by its expansile invasive nature. Thus an inflammatory lesion may be mistaken for neoplastic growth and vice versa which can lead to erroneous diagnosis, improper therapy and poor outcome.