Actinomycosis masquerading as a nasal polyp - a rare entity and diagnostic challenge

Actinomycosis is an endogenous bacterial infection caused by Actinomyces israelii. This bacterium reside on the mucosa of oral cavity, tonsils, and genitourinary tract. Any insult such as trauma, surgery, or foreign body disrupts the mucosal barrier and gives entry to the underlying tissue to cause disease. We describe a rare presentation of Actinomycosis presenting as a nasal polypoidal mass in a young female, an uncommon presentation, thereby causing diagnostic challenge as it may mimic other lesions with similar clinical presentations like fungal polyps, allergic polyps or chronic sinusitis. A 22 year old female presented with history of recurrent upper respiratory tract infection to the ENT Outpatient Department, clinical evaluation showed deviated nasal septum and radiology showed a nasal polyp and patient underwent submucosal resection with middle meatal antrostomy and micro-debrider assisted polypectomy. Histopathology showed respiratory epithelium with underlying stroma showing dense basophilic filamentous organisms surrounded by peripheral eosinophilic clubs that were Gram-positive and Gomori Methanamine Silver stain positive. The disease was diagnosed as Actinomycosis. The disease is a mimicker of various diseases such as nocardiosis, botryomycosis or tuberculosis having a wide range of symptoms and affecting multiple organs. Prevalence of actinomycosis in nasal region is rare thereby increasing the risk of misdiagnosis. Thus, Actinomycosis should be kept as a differential diagnosis in any chronic infectious diseases of the nasal cavity and monitored closely to ensure precise diagnosis and timely management.