T-cell Lymphoma of the Temporal Bone Presenting as Mastoiditis With a Facial Palsy

T-cell lymphoma of the temporal bone is a rare malignancy frequently mimicking chronic otomastoiditis.We report a 56-year-old male with peripheral T-cell lymphoma (PTCL) transformed from indolent T-cell lymphoproliferative disorder (iTLPD-GI), with a prior monoclonal tongue lesion confirmed by T-cell receptor gamma gene rearrangement.The patient presented with hearing loss and House-Brackmann grade IV facial palsy, and the imaging revealed facial nerve canal dehiscence at the first genu and atypical pachymeningeal enhancement.Due to clinical urgency, emergency radical mastoidectomy was performed for decompression and biopsy, which confirmed aggressive clonal transformation.Initial remission was achieved; however, systemic relapse occurred at 18 months with partial nerve recovery to HB grade III.Refractory mastoiditis with early cranial neuropathy warrants high suspicion of malignancy, especially in patients with lymphoproliferative histories.Vigilant surveillance is vital as indolent T-cell clones may undergo rapid extranodal transformation into aggressive malignancies.