Thymoma is a term that should be restricted to neoplasms of thymic epithelial cells, irrespective of the presence or the number of lymphocytes. The usual location of thymoma is the antrosuperior mediastinum; however, this tumor can also occur in other mediastinal compartments, in the neck, within the thyroid gland, in the pericardial cavity, the pulmonary hilum, within the lung parenchyma, or the pleura itself (sometimes coating it in a mesothelioma-like fashion). The association of thymoma with hypogammaglobulinemia, Mucocutaneous candidiasis, systemic lupus erythematosus and myasthenia gravis is well known. Here we present a patient admitted in our hospital with buttock rashes regarded to be zoster of the buttock. In his past medical history he had recurrent cutaneous infections, lupus erythematosus, hypergammaglobulinemia, recurrent oral candidiasis and B- cell dysfunction. During the patient evaluation, a mass was found in the mediastinum and percutaneous needle biopsy confirmed the diagnosis of thymoma(type B3). This is the second case reported having thymoma in association with hypergammaglobulinema.