Intracranial temporal bone angiomatoid fibrous histiocytoma: illustrative case

BACKGROUND: Angiomatoid fibrous histiocytoma (AFH) is a rare, slowly progressive neoplasm that most commonly occurs in soft tissues. AFH rarely occurs in bone such as the calvaria. The authors present a case of AFH in the petrous temporal bone, which, to their knowledge, is the first case of AFH in this location. OBSERVATIONS: A 17-year-old girl presented with worsening positional headaches with associated tinnitus and hearing loss. Imaging demonstrated an extraaxial mass extending into the right cerebellopontine angle, with erosion of the petrous temporal bone, with features atypical for a benign process. The patient underwent retrosigmoid craniotomy for tumor resection. Pathology was consistent with a spindle cell tumor, and genetic testing further revealed an EWSR1 gene rearrangement, confirming the diagnosis of AFH. The patient was discharged with no complications. Her symptoms have resolved, and surveillance imaging has shown no evidence of recurrence. LESSONS: The authors report the first case of AFH in the petrous temporal bone and only the second known case in the calvaria. This case illustrates the importance of the resection of masses with clinical and imaging features atypical of more benign entities such as meningiomas. It is important to keep AFH in the differential diagnosis for atypical masses in the calvaria and skull base.