Unveiling complexity: Chest wall swelling manifestation of extramedullary myeloma

Abstract

There are two forms of myeloma: Solitary plasmacytoma and multiple myeloma. Both are malignant tumors and develop from bone marrow plasma cells, which secrete immunoglobulins. Pleural effusion secondary to myeloma is extremely rare, with an incidence of 1–2%. A 58-year-old man presented to the emergency department with a chief complaint of swelling and pain over the left side of his chest, breathlessness, generalized weakness, abdominal pain, and blood in his stool for 15 days. The chest X-ray posteroanterior view showed well-defined homogenous opacity in the left hemithorax. The patient underwent ultrasound-guided left-sided thoracocentesis. Pleural fluid was exudative, and cytology showed the presence of malignant cells. Contrast-enhanced computed tomography of the thorax and abdomen showed a well-defined soft-tissue density lesion involving the left posteriolateral chest wall with underlying rib erosion. For confirmation of malignant etiology, a USG-guided transthoracic needle biopsy was performed. A biopsy revealed a malignant round cell tumor in a histopathological review. For confirmation, a tissue sample was sent for immunohistochemistry markers, which had positivity for CD 138 and MUM 1, consistent with myeloma. Rarely, MM can present as chest wall swelling. Ultrasound is an easily available diagnostic modality that can be used for chest wall biopsy with a minimal incidence of complications.