Temporal bone plasmacytoma: An exceptional localization of solitary bone plasmacytoma highlighting the role of multimodal imaging and multidisciplinary management.

Solitary plasmacytoma (SP), a rare form of plasma cell neoplasm, is characterized by the monoclonal proliferation of plasma cells in a localized bone or soft tissue lesion. Temporal bone plasmacytoma is an uncommon manifestation of this condition, often presenting with nonspecific symptoms such as hearing loss, tinnitus, and cranial nerve deficits. The diagnosis is frequently challenging, given the overlap with other pathologies such as cholesteatoma and paragangliomas. Histopathological examination typically reveals sheets of plasma cells, which are confirmed by immunohistochemistry for light chain immunoglobulin, with Kappa light chains commonly identified in a majority of cases. The standard management of solitary plasmacytoma of the temporal bone includes local radiotherapy, with surgery reserved for biopsy or cases of neurological compromise. The prognosis is generally favorable with appropriate treatment, although continuous monitoring is necessary due to the risk of progression to multiple myeloma, a disseminated form of plasma cell malignancy. This case highlights the importance of differential diagnosis in temporal bone lesions and the critical role of immunohistochemical studies in confirming monoclonality, aiding in the management and long-term follow-up of affected patients. We present the case of a 65-year-old female patient with a known history of hypertension, managed with dual therapy, who presented to our institution with a progressively enlarging right temporal mass over the course of approximately 10 months. A comprehensive clinical evaluation, supported by laboratory tests and imaging studies, led to the diagnosis of a plasmacytoma of the temporal fossa. Given the extreme rarity of this condition and its potential clinical overlap with other head and neck pathologies, particularly those affecting the ENT sphere, it is crucial to maintain a high level of clinical suspicion to prevent diagnostic delays. Early diagnosis and prompt intervention are essential. Management requires a multidisciplinary approach, tailored to each individual case, to optimize oncological and functional outcomes while preserving the patient's quality of life.