Gamma heavy-chain disease accompanied with follicular lymphoma: a case report.

Heavy chain diseases (HCD) are B-cell lymphoprolipherative disorders characterized by the production of monoclonal heavy chains without associated light chains. Some cases of gamma-HCD (γ-HCD) are concurrent with other lymphoid neoplasm. The monoclonal component is not always detectable by serum electrophoresis, and often an immunofixation procedure is necessary to detect this component. Prognosis is variable, and no established guidelines for follow-up are available. We describe a case of a challenging diagnosis of γ-HCD due to the absence of clinical signs frequently reported in the disease (anaemia and palatal oedema among others). Haematological malignancy was the first suspicion but bone marrow examination was negative. In addition, the presence of an autoimmune bicytopenia and a Klinefelter syndrome complicated the clinical context of the patient. A thoracoabdominal computed tomography reported many small adenopathies whose pathological and immunohystochemical study revealed a follicular lymphoma. Shortly after, serum inmunofixation secondary to an abnormal electrophoretic pattern revealed a gamma paraprotein without light chains. Eventually, γ-HCD in association with follicular lymphoma was the final diagnosis. This is the first case reporting this association.