[Cutaneous localization of multiple myeloma on the tract of a central venous catheter].

INTRODUCTION: Extramedullary plasmocytoma are plasmocytic tumours developing outside of the bone marrow. Cutaneous localization of extramedullary plasmocytoma are rare and can be primitive or secondary. We report two cases of secondary extramedullary plasmocytoma occurring on central venous catheterization sites. OBSERVATIONS: A 68 year-old woman and a 69 year-old man presented with subcutaneous metastases located along the tracts of central venous catheters or implantable ports, which were either still on site or removed recently. Although the patients initially responded to melphalan therapy, they eventually died of multiple myeloma a few weeks following the diagnosis of the cutaneous localizations. DISCUSSION: Extramedullary plasmocytoma are most commonly found in the upper respiratory tract, the gut and the lymph, but cutaneous localization is rare. We report two cases of cutaneous extramedullary plasmocytoma located on the tract of central intravenous infusion sites. Both patients were treated with melphalan with initial improvement, followed by an early relapse. Two cases of myeloma metastases occurring on the tract of central venous catheters have previously been published. This localization seems to occur late in the course of this disease and to be associated with a poor prognosis.