Histopathological Approach in Diagnosis of Mycetoma Causative Agents: A Mini Review

Mycetoma is a unique neglected tropical disease which distributed worldwide and endemic in tropical and subtropical regions. This disease is caused by a large number of micro-organisms of fungal (eumycetoma) or bacterial (Actinomycitoma) origins. The disease is characterized by a swelling in the cutaneous and subcutaneous tissues, with the formation of sinuses tract in some patients with numerous deformities and disabilities. Mycetoma infection affects all ages. The diagnosis of the mycetoma is based on identification of the causative organism and the disease extension which in turn considered as the first steps in the management of the affected patients and eventually predicting disease treatment outcome and prognosis. Different diagnostic tools were developed that aimed to identify the causatives agent. These include direct microscopy, Fine needle aspiration, Imprint cytology, histopathological, culturing techniques and molecular identification. Since histopathology is continues to be a rapid diagnostic tool as well as cost effective means of providing a presumptive or/and in some instances a definitive diagnosis of an invasive mycetoma infection, as well as it able to detect the causative agents invasion of tissues and vessels as well as host tissue reaction to the causative agents, however no way to replace the culture and molecular diagnosis that remain the most powerful tools for the definitive diagnosis of the causative agents. In our clinical setting at Mycetoma Research center the histopathology report, considered as a powerful tool as it include a comment stating the morphological appearance of the causative agents and the type of the host tissue reactions as well as it stated clearly the possible differential diagnosis. In this review we will discuss varies histopathological appearance of mycetoma causative agents as well as the common used histochemical stains that can aid in the diagnosis and the host tissue reaction to varies causative agents.