Extramedullary relapse of Immunoglobulin A-kappa myeloma manifesting as plasmacytoma of the pleura without bone marrow involvement and following autologous bone marrow transplant: a case report

BACKGROUND: Recurrence of multiple myeloma is among the most challenging issues for patients and treating physicians reported after autologous stem cell transplantation. However, extramedullary involvement after chemotherapy and transplantation has been rarely reported, especially as pleural manifestations. Protein electrophoresis indicated immunoglobulin A monoclonal kappa plasma cell neoplasm in our case. CASE PRESENTATION: A 48-year-old middle-eastern man was referred to our clinic with cough, dyspnea, fever, and left side pleural effusion. A year after chemotherapy and autologous bone marrow transplantation, the patient presented with features in favor of pleural relapse, without bone marrow involvement. Protein electrophoresis demonstrated immunoglobulin A monoclonal kappa plasma cell neoplasm in our case. The patient was effectively treated with dexamethasone, thalidomide, cisplatin, doxorubicin, cyclophosphamide, and etoposide with no notable adverse effects. CONCLUSION: Physicians should be aware of various presentations of multiple myeloma relapse, especially in autologous stem cell transplantation patients. Atypical and unique presentations such as the pleural involvement warrant further reporting of evidence to provide early management and treatment options.