High-Grade Temporal Bone Sarcoma Mimicking Cholesteatoma During Pregnancy: A Diagnostic Pitfall and Multidisciplinary Challenge.

Osteosarcoma of the head and neck is an uncommon malignancy with heterogeneous clinical and radiological presentations, often leading to diagnostic challenges. Its occurrence during pregnancy further complicates management due to the need to balance maternal and fetal outcomes. We report the case of a 23-year-old pregnant woman who initially presented with right-sided otalgia, managed as otitis externa. She subsequently developed a rapidly progressive, highly vascular mass protruding through the external auditory canal, associated with conductive hearing loss and vestibular symptoms. Magnetic resonance imaging revealed an aggressive lesion involving the external auditory canal, middle ear, and mastoid air cells and extending to the dura of the middle and posterior cranial fossae. An initial biopsy performed at 17.5 weeks of gestation was suggestive of cholesteatoma. However, due to clinical progression, surgical resection via mastoidectomy was performed. Definitive histopathological analysis revealed a high-grade spindle cell and epithelioid sarcoma with osteoid formation, consistent with osteosarcoma. The patient developed early recurrence with intracranial progression, requiring multidisciplinary management. Radiotherapy was initiated at 28 weeks of gestation, followed by termination of pregnancy at 29 weeks due to maternal oncologic progression and oligohydramnios. Systemic chemotherapy was subsequently administered, achieving a partial response. In our case, the lesion was initially approached as a benign otologic condition, which delayed definitive diagnosis despite imaging findings suggestive of aggressive disease. Both clinical evaluation and initial histopathological assessment failed to establish the correct diagnosis. This case also underscores the complexity of oncologic decision-making during pregnancy and the critical importance of a multidisciplinary approach.