Periportal Collar Sign: A Potential Sonographic Pattern of Multiple Myeloma

Multiple myeloma is a malignant bone tumor caused by a monoclonal proliferation of plasma cells that spreads from the red marrow to all parts of the body, causing multiple lesions. The typical lesions result in multiple fractures and may be associated with renal failure, hypercalcemia, anemia, and recurrent infections. Diagnosis usually requires demonstration of M-proteins and/or light chain proteinuria and an excess of plasma cells, in the bone marrow, which requires a biopsy. Sonography is a highly sensitive and repeatable diagnostic technique that could allow for the detection of pathognomonic signs and facilitate the diagnosis. In the case presented, sonography revealed a very rare diagnostic sign: the “periportal collar” which is given by the decrease in echogenicity of the periportal areas. There are several interpretations of this sign, which could indicate liver tumors, inflammation of the biliary tract, amyloidosis, hypertension, and portal thrombosis. Periportal collar has never been described in multiple myeloma, and this finding could be a pathognomonic sonographic sign of the disease. This study describes a case of the “periportal collar” sign detected by sonography and computed tomography in a patient with metastatic multiple myeloma.