Role of histopathology as an aid to prognosis in rhino-orbito-cerebral zygomycosis

Rhino-orbito-cerebral zygomycosis is a rapidly progressive opportunistic fungal infection characterized by a set of clinical and radiological findings that help in prognostication. The present study is aimed to evaluate its histopathologic features as an aid to prognosis in order to guide the physician at the stage of tissue diagnosis to optimize surgery, chemotherapy and immunosuppression. The study comprises of a microscopic analysis of specific histopathologic variables on 33 cases of zygomycosis that were diagnosed and treated in a seven-year period. Fungal load in the tissue (graded as mild, moderate and marked), mean diameter of fungus, degree of neutrophilic and granulomatous response, tissue invasion and necrosis were graded and assessed for their prognostic significance. Seasonal variation, signs and symptoms, extent of involvement and laboratory parameters were also analyzed to examine the trend of occurrence of the disease and to associate these with patient's outcome, which was categorized as either survived or expired. The follow-up ranged from 1 month to 7 years. Of all the histological variables, angioinvasion was directly related to the mortality rate. Diameter of the fungal hyphae and its intraorbital or intracranial invasion also proved to be significant indicators of poor prognosis. (P = 0.04 and 0.0037, respectively) though angioinvasion was directly related to the mortality rate. Thus, histopathology could assist the clinician in assessing patient's progress and thus optimize the treatment in such patients.