Chemotherapy responsiveness in a patient with multiply relapsed ameloblastic fibro-odontosarcoma of the maxilla

Abstract

Ameloblastic fibro-odontosarcoma (AFOS) is an extremely rare malignant odontogenic tumor. Complete surgical excision is the treatment of choice. Deaths due to disease recurrence and/or progression are documented. Here, we report the case of a 15-year-old female with multiple recurrent AFOS. She responded to chemotherapy with ifosfamide and doxorubicin consolidated by stereotactic reirradiation using cyberknife and remained in complete remission 14 months from the end of reirradiation therapy. Chemotherapy with ifosfamide and doxorubicin should be considered in advanced cases of AFOS.

Keywords: ameloblastic fibro-odontoma; ameloblastic fibro-odontosarcoma; chemotherapy response; radiotherapy; relapse; transformation.

Figure 1

Histologic findings in the AFO and AFOS specimen and on MRI prior to first relapse. (A,B) Hematoxylin–eosin (HE) stained sections of the initial tumor [ameloblastic fibro‐odontoma (AFO)]. (A) Small islands and branching cords of ameloblastic epithelium are interspersed within spindle cell stroma. The mesenchymal component is of moderate cellularity, but no pleomorphism is present and mitotic activity is low (up to 2/10 hpf; magnification 100×. (B) Other areas show odontogenic epithelium and dentine; magnification 40×. (C,D) HE‐stained section of the first tumor recurrence [ameloblastic fibro‐odontosarcoma (AFOS)]. (C) The prominence of the mesenchymal (spindle cell) component is apparent and is of higher cellularity than the initial AFO; magnification 40×. (D) The fascicular fibrosarcoma‐like architecture of the spindle cell component is discernible in areas, and only a small island of epithelium is seen here (top left). There is a focal mild atypia, and increased mitotic count of the mesenchymal component (5/10 hpf); magnification 100×. (E) Surveillance MRI 4 months after completion of radiotherapy for AFOS with involved margins. T2‐weighted sequence shows focal area of high signal (arrows) lying on lateral wall of right orbit, involving right temporalis muscle. (F) HE‐stained section of the first relapse of AFOS. The tumor shows more aggressive morphology, with prominent cellularity and pleomorphism of the mesenchymal component, along with numerous mitotic figures (arrows) and a significantly increased mitotic index of 17/10 hpf. The tumor is seen to extensively infiltrate skeletal muscle fibres. The epithelial component is markedly reduced and is not seen in this field; magnification 200×.

Figure 2

MRI findings prior to and after chemotherapy with ifosfamide and doxorubicin. (A) MRI findings of second relapse of AFOS: T2‐weighted MRI demonstrates a lobulated mass returning high signal, at the site of resected tumor. Post‐surgical baseline imaging less than 3 months earlier had shown no lesion at this site. Note that soft tissue penetrates into the middle cranial fossa and orbit (arrowheads). (B) Response to six cycles of chemotherapy with ifosfamide and doxorubicin on MRI: T2‐weighted MRI demonstrates resolution of the mass lesion (arrow). Some residual fatty change is present. Cyberknife radiotherapy was subsequently administered to the tumor bed.