Totally implantable venous access port metastasis in a patient with multiple myeloma

Multiple myeloma is a hematologic malignancy characterized by the proliferation of monoclonal plasma cells within the bone marrow. Extramedullary plasmacytomas, a rare manifestation of multiple myeloma, occur in a small percentage of patients. These plasmacytomas can develop in the skin, often near venous catheter access sites, posing diagnostic challenges due to their rarity. We report a case of a 63-year-old man with multiple myeloma who presented with a mildly painful, swollen left chest port site. A whole-body FDG PET/CT scan revealed a hypermetabolic soft tissue mass surrounding the port site, suggestive of malignancy. Subsequent surgical excision and histopathological analysis confirmed the presence of a metastatic subcutaneous plasmacytoma, consistent with the patient's known multiple myeloma. Cutaneous extramedullary plasmacytomas at central venous catheter sites are rarely reported. Potential mechanisms for tumor development at trauma sites include local expression of chemokines that attract myeloma cells. This case underscores the importance of recognizing cutaneous plasmacytomas in patients with multiple myeloma and venous access ports to avoid misdiagnosis and unnecessary interventions. It contributes to the broader understanding of extramedullary disease manifestations in multiple myeloma and emphasizes the need for thorough investigation and appropriate management in such cases.