Initial magnification20 (a) and40 (b) A complete search for distant metastasis by positron emission tomography and by enhanced computed tomography of the chest, abdomen, and pelvis produced no results. all irradiated patients [1, 2] and 5. 5 % of all osteosarcomas [2]. This incidence could increase in the future because radiation therapy has become more common and developed, and patient survival offers improved. Reports of radiation-induced osteosarcoma from the skull base are limited to a small series and some case reports. In this report, we describe a very rare case of skull base radiation-induced osteosarcoma in a patient treated with ionizing radiation intended for undifferentiated carcinoma of the nasopharynx. == Case presentation == A 29-year-old Moroccan man presented to our hospital with a 6-month history of headache in his left skull, associated with homolateral facial pain, numbness, diplopia, exophthalmia, vision watering, and an episode of epistaxis. Eleven years before, he had received radiotherapy for undifferentiated carcinoma from the nasopharynx, initially classified because T1N1M0. The radiation dose he had received was 70 Gy in 35 fractions delivered using the classic 3-fields technique (2 lateral opposed fields abutted to an anterior low-neck field). This technique had been applied during the previous 20 years because it seemed to be the simplest. The patients physical examination revealed a left ptosis, hemifacial edema, and decreased visual aesthetics. Magnetic resonance imaging disclosed a GSK221149A (Retosiban) tumor process of the skull base involving the sphenoid bone with its two left wings, the squamous part of the left temporal bone, and the left maxillary bone, associated with intracranial expansion, as well as a second, isolated mass in the temporal lobe (Fig. 1). == Fig. 1 . == Magnetic resonance imaging studies show a tumor process of the skull base involving the sphenoid bone with its two left wings, the squamous part of the left temporal bone, associated with intracranial expansion, as well as a second, isolated mass in the temporal lobe. aT1-weighted, gadolinium-enhanced axial magnetic resonance imaging scans. bT1-weighted, axial magnetic resonance imaging scans. cT2-weighted axial magnetic resonance imaging scans Direct nasofibroscopy with biopsy was performed. The histological results with immunohistochemistry were in favor of osteosarcoma with all the following characteristics: spindle-cell neoplasm pleomorphism with badly limited cytoplasm, an irregular nucleus with frequent atypical mitoses, and an associated osteoid matrix. The results of immunohistochemistry with anti-AE1/AE3, anti-endomysial antibodies, and anti-CD34/CD31 were negative (Fig. 2). == Fig. 2 . == aandbHigh-grade osteosarcoma with spindle-cell pleomorphic neoplasm, badly limited cytoplasm, and osteoid matrix. Initial magnification 20 (a) and 40 (b) A complete search for distant metastasis by positron emission tomography and by enhanced computed Rabbit Polyclonal to DYNLL2 tomography of the chest, GSK221149A (Retosiban) abdomen, and pelvis produced no results. We reviewed the initial pathology and documentation GSK221149A (Retosiban) outlining the patients initial radiation therapy and confirmed that the tumor developed in the previously irradiated field. The tumor was deemed unresectable, and further radiation therapy was not advised. The patient was started on chemotherapy consisting of four cycles of ifosfamide, cisplatin, and doxorubicin, to be followed by four planned cycles of doxorubicin and ifosfamide. A physical evaluation after the second cycle revealed improvement of clinical signs, but after GSK221149A (Retosiban) this initial remission, the patients condition deteriorated, and he died 1 month after his third cycle of chemotherapy. == Discussion == Radiation therapy intended for head and neck cancer is a well-accepted modality of treatment. It is a standard treatment for carcinoma of the nasopharynx. However , as with all treatment modalities, there are short- and long-term morbidities and occasionally mortalities. One of the most dreaded complications of radiation therapy is the formation of new malignancies. Although difficult to estimation, the incidence of radiation-induced tumors is very low [3]. The most frequent radiation-induced tumors are fibrosarcoma and osteosarcoma. Sarcomatous tumors take into account most radiation-induced neoplasms involving the head and neck, and most occur in the facial skeleton. Very few involve the skull base [47]. Postirradiation osteosarcomas are rare, accounting for 36 % of all cases of osteosarcoma and 0. 010. 03 % of all irradiated patients [1, 2]. The incidence of radiation-induced tumors is increasing in the oncology populace as a result of increased survival through the development of cancer treatment [8]. Cahanet al. explained the following criteria for radiation-induced sarcoma: (1) The initial and secondary.