Mass Confusion: A Liquid Cancer’s Solid Disguise

Title: Mass Confusion: A Liquid Cancer’s Solid Disguise
Authors: Bailey Kelson, Michal Niwinski
Date: 1/27/2025
Abstract: A 58-year-old man with acute onset dyspnea and leg edema was admitted through the ED when evaluation revealed elevated BNP, leukocytosis, troponin elevation, and interstitial edema. A provisional diagnosis of NSTEMI resulting from acute-on-chronic HFpEF was made. Methods: Echocardiogram revealed no regional wall motion abnormality but did show diastolic dysfunction with apical sparing suggestive of cardiac amyloidosis, prompting a PYP scan that returned negative for TTR amyloid. Management of HFpEF was initiated, and urine and serum protein electrophoresis were requested. Interestingly, leukocytosis increased despite NSTEMI resolution; the development of vomiting and abdominal pain prompted an abdominopelvic CT after which the patient electively discharged home. Results: The radiologist’s report later noted numerous mesenteric solid masses concerning for malignant lymphadenopathy. On outpatient follow-up, repeat CT to identify the optimal biopsy site revealed that the mesenteric nodules had surprisingly decreased in size and intensity. This prompted reinterpretation as resolving hemorrhagic foci from amyloid angiopathy. Urine electrophoresis returned showing monoclonal gammopathy, and bone marrow biopsy confirmed the diagnosis of multiple myeloma. After discussing prognosis and treatment options, the patient elected for comfort care. Conclusion: This case illustrates the importance of recognizing AL amyloid-associated disease, including amyloid angiopathy, as possible manifestations of multiple myeloma. Amyloid angiopathy can occur via vascular fragility and multiple mechanisms that disrupt primary and secondary hemostasis. AL amyloid may also present with nephrotic-range proteinuria, macroglossia, hepatomegaly, peripheral neuropathy, or purpura. Here, the unifying diagnosis was delayed by a spurious CT finding of lymphadenopathy, which is not characteristic of multiple myeloma; this distracted from echocardiographic evidence of an amyloid-producing disease. Additionally, while cardiac technetium scans are invaluable for the non-invasive detection of transthyretin amyloidosis, they are insensitive in detecting amyloid of other compositions and must be combined with monoclonal protein studies to confidently rule out amyloidosis. Recognizing the connection between plasma cell dyscrasias and amyloidosis is critical to the timely identification of potentially malignant underlying mechanisms of amyloidosis. By drawing attention to the heterogeneity of this illness’ presentation, we hope to spare similarly presenting patients the time spent contemplating the presence of “solid tumors” and move them more quickly toward a hematologic malignancy work-up. Additional Context: This patient was unable to be reached once his CT results had raised concern for malignancy. His outpatient workup would have been significantly delayed had he not been part of Rose Park’s pilot program bridging patients from inpatient to outpatient. Had we not met him prior to his unexpectedly early discharge, he would have been lost to follow-up.

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Mass Confusion: A Liquid Cancer’s Solid Disguise by Bailey Kelson & Michal Niwinski