Fungal infections continue to cause major complications in
cancer patients. With the increasing use of aggressive
chemotherapy and
stem cell transplantation causing profound, prolonged depressed immunity, the risk of
invasive mycoses has increased. The prognosis of these
infections is poor unless they are diagnosed and treated promptly. The management of opportunistic
fungal infections is characterized by a series of unresolved problems, including initial difficulties in obtaining an early diagnosis. Clinical signs indicating a definite diagnosis of
fungal infection is frequently absent in
cancer patients. There are no distinctive symptoms and
fever is the most common and, frequently, the only sign. In only a minority of cases, and usually after recovery from
neutropenia, can some clinical features, such as pulmonary pseudomycetoma and hepatosplenic lesions, be suggestive of an invasive mycosis. Thus, laboratory procedures are necessary to reveal or confirm the diagnosis of invasive mycosis and establish disease etiology. Cultures are often negative and positive results need a careful evaluation to determine clinical importance. The significance of fungi isolated from mucosal surfaces and from the respiratory tract in diagnosing
invasive mycoses is controversial. The problem in interpreting these microbiological data is the differentiation between
fungal infection and colonization. Detection of
fungal antigens by molecular methods appears to be promising, but the significance in various clinical settings is still under evaluation. In most cases, the diagnosis depends on a combination of clinical, microbiological, histological and serological results.