[Opportunistic infections in patients after complex therapy of cancer]

An opportunistic infection is an infection caused by pathogens, such as Toxoplasma gondii, that usually are not pathogenic in a healthy host but may cause an infection in immunocompromised patients. Although the most frequent cause of an opportunistic infection is immunodeficiency due to HIV infection, the immunodeficiency induced by anticancer treatment cannot be ignored.

A 56-year old female patient after a comprehensive treatment of breast cancer underwent a stereotactic biopsy of MR-verified multiple brain lesions suspected to be of metastatic aetiology. The histology report unexpectedly concluded that the lesion was brain toxoplasmosis confirmed by detection of IgM specific antibody in cerebrospinal fluid. Immunology examination has proven a deficit of cell-mediated immunity. The symptoms (cephalea, cerebellar symptomatology with vertigo) and MR findings disappeared following 6-month treatment with a combination of pyrimethamin, sulfadiazin and leucovorin.

Since neoplastic duplicities and brain lesions of non-neoplastic aetiology are found in about 11% of oncology patients, histological verification of aetiology of intracranial lesions is essential for targeted therapy of these patients. Our case of brain toxoplasmosis documents the role of opportunistic infections in differential diagnosis of brain lesions in patients who underwent anticancer treatment.