Introduction Immunocompromised patients have a predisposition to infections because of their weakened immune system. Thus,a fungal infection in the head area with entry points of the sinuses can induce massive destruction of the surrounding tissue, as in the case described below. Case report As part of a chemotherapeutic treatment of acute lymphocytic leukemia a 3½ year old boy developed a fungal infection of the paranasal sinuses. In addition, there was a Trisomy 21. initially he showed clinical an incipient necrosis in the area of the right nostril. In a nasal swab Aspergillus could be detected. Despite a supportive antifungal therapy, there was a progress of fungal disease with an invasive and destructive growth component. After regeneration of the blood formation and improvement of the general condition of the patient was a radiological diagnosis and surgical intervention possible. An MRI of the head and neck showed a necrosis of the septum and the tip of the nose to the right lateral nasal wall. Similarly, there was a necrosis of the hard palate and anterior alveolar ridge right in front. The neck and lungs could not be found pathological findings. In an interdisciplinary approach of the maxillofacial and ENT clinics the necrotic nose, the anterior maxilla including parts of the paanasal sinuses had be resected. The Defect of the palate was supplied by inserting a tampon and covered with a plate. Afterwards the defect in the nose area was supplied with an epihesis the of nose. Conclusion The dramatic developments of the case shows that the benefit of chemotherapy for acute lymphoblastic leukemia can have a high price. This may take up to a massive tissue loss in functional and aesthetically important regions of the face. As the benefit of chemotherapy unquestionable is, knowledge of such potential complications is important in order through early intervention. Keywords: Leukemia, fungal infection, necrosis, tissue loss nose and jaw