Resolution of immune thrombocytopenic purpura associated with extranodal B-cell lymphoma of the petroclival region after radiotherapy

BACKGROUND Secondary immune thrombocytopenic purpura (ITP) associated with extranodal B-cell non-Hodgkin's lymphoma (NHL) is extremely rare. The optimal management is not established. We report a first case of ITP in association with extranodal B-cell NHL originating in the lower petroclival region, successfully managed by local tumor control using conventional radiotherapy. CASE DESCRIPTION A 75-year-old man presented with a two-month history of hearing loss, hoarseness, and dysphagia. Neuroimaging revealed a large enhanced lesion in the left lower petroclival bone near the jugular foramen. Isolated unilateral parotid lymphadenopathy was also noted. Preoperative laboratory findings were normal, except for elevation of serum soluble interleukin-2 receptor level. A suboccipital craniotomy was performed and a biopsy sample was taken. Histological and immunohistochemical examination confirmed small B-cell lymphoma with plasmacytic differentiation. After initiation of radiotherapy, thrombocytopenia (24,000/µl) rapidly developed. Serological and bone marrow examination confirmed ITP. Prednisone was given at 1 mg/kg/day and radiation therapy was continued. After more than 32Gy, platelet count rapidly normalized. Radiotherapy to the tumor site achieved local tumor control and ITP was resolved. No evidence of recurrence and normal platelet count were confirmed at the two-year follow-up examination. CONCLUSION Local control of the tumor was considered important in the resolution of secondary ITP in association with extranodal NHL of the skull base region.