Wiskott-Aldrich syndrome complicated with IgG4-related Sclerosing disease: A case report and literature review.

Wiskott-Aldrich Syndrome (WAS) is an X-linked immunodeficiency characterized by eczema, microthrombocytopenia, and recurrent infections. Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory disorder involving various organs. We present a 34-year-old male with WAS who developed cervical lymphadenopathy and parotid gland swelling. Initial biopsies were inconclusive and imaging suggested pleomorphic adenoma. Given the persistent cervical lymphadenopathy and the underlying immunodeficiency, lymphoma was also considered in the differential diagnosis. However, histopathological examination of excised salivary gland and lymph nodes revealed lymphoplasmacytic and eosinophilic infiltrates, numerous IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis, consistent with IgG4-RD. The patient responded well to prednisone therapy. This case emphasizes the importance of considering IgG4-RD in the differential diagnosis of lymphoproliferative lesions in immunodeficient individuals and highlights the diagnostic value of histopathological evaluation in excisional tissue specimens. To our knowledge, this represents a rare coexistence of WAS and IgG4-RD not previously reported in the literature.