Mycobacterium leprae, the causative agent of leprosy, primarily involves tissue macrophages (2). The first line of defense in leprosy is cellular immunity (2). Neural inflammation is the characteristic finding that helps in differentiating leprosy from other granulomatous diseases. Nasal involvement is common in leprosy (2). Nasal septal perforation is a significant finding in the late stage of leprosy causing saddle nose deformity.
Rhinoscleroma is divided based on the clinical signs into three distinct stages, namely the catarrhal stage, the proliferative or granulomatous stage and the sclerotic or fibrotic stage (5). The most characteristic histological finding of rhinoscleroma is formation of Mikulicz cells and Russell bodies, especially in the granulomatous stage (4). Mikulicz cells are large foamy phagocytes with peripheral nuclei and multiple cytoplasmic vacuoles that contain Klebsiella bacilli (5, 6). Russell bodies are eosinophilic inclusions in a plasma cell that undergo synthesis of immunoglobulin (7). Although bacterial culture is positive in 50% of cases in the granulomatous stage (5), the mainstay of diagnosis is histopathological examination. Mikulicz cells is the pathognomonic feature for diagnosis (6).
Nasal granulomatous diseases such as leprosy, tuberculosis and Wegener’s disease should be distinguished from the granulomatous stage of rhinoscleroma. The most common site of involvement in rhinoscleroma is nasal mucosa (4, 8). The usual clinical presentation is bilateral nasal discharge and crusts (6). Genetic susceptibility may be a predisposing factor (4, 5). Low socio-economic condition is assumed as a co-factor (9).
Impaired cellular immunity and reversal of CD4:CD8 ratio are common pathophysiological findings in both leprosy and rhinoscleroma (5). Although co-involvement of leprosy and other granulomatous infectious diseases (e.g., tuberculosis) has been reported (10), rhinoscleroma has never been described in a patient with any coexisting chronic granulomatous disease, especially leprosy (5). Nasal involvement, the main presentation of rhinoscleroma, is common in both diseases; on the other hand the histologic diagnosis of rhinoscleroma is somehow difficult; therefore, rhinoscleroma may be missed in a patient with coexistence of leprosy and rhinoscleroma.
The objective of presenting this case was to highlight the importance of possible coincidence of two granulomatous infectious diseases with similar pathophysiologies. Impaired cellular immunity in leprosy can predispose patients to other diseases such as rhinoscleroma, which involve cell-mediated immunity. Failure to diagnose can lead to residual nasal symptoms despite appropriate treatment of leprosy.
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