Waldenström macroglobulinemia with secondary pure red cell aplasia in a patient with metastatic castrate resistant prostate cancer receiving an immune checkpoint inhibitor: a case report

• Published in: Journal of medical case reports 2023-05, Vol.17 (1), p.220-220, Article 220
• Main Authors: Kumar, Vaibhav, Montgomery, Nathan D, van Deventer, Hendrik W, Whang, Young E
• Format: Article
• Language: English
• Subjects: Aged; Anemia; Anemia - chemically induced; B cells; Bendamustine; Biopsy; Bone marrow; Cancer therapies; Case Report; Case reports; Development and progression; Drug therapy; Health aspects; Hemoglobin; Humans; Immune Checkpoint Inhibitors; Immunotherapy; Lymphoma; Lymphoproliferative Disorders; Male; Metastasis; Mutation; Patients; Prostate cancer; Prostatic Neoplasms - complications; Pure red cell aplasia; Red-Cell Aplasia, Pure - chemically induced; Red-Cell Aplasia, Pure - complications; Red-Cell Aplasia, Pure - drug therapy; Waldenstrom Macroglobulinemia - complications; Waldenstrom Macroglobulinemia - drug therapy; Waldenström macroglobulinemia; White people
• ISSN: 1752-1947; 1752-1947
• DOI: 10.1186/s13256-023-03948-4

Hypoproliferative anemia is a frequently encountered adverse event in cancer patients receiving immune checkpoint inhibitors (ICI). Secondary pure red cell aplasia (PRCA) is a rare but recognized immune related adverse event. With the burgeoning use of ICIs, the association of secondary PRCA with an underlying lymphoproliferative disorder is often overlooked. We report a case of a 67-year-old non-Hispanic Caucasian male with metastatic castrate resistant prostate cancer, who developed severe transfusion dependent anemia with reticulocytopenia while receiving treatment with olaparib and pembrolizumab. His bone marrow findings demonstrated erythroid hypoplasia, in addition to a CD5-negative, CD10-negative monotypic B-cell population and a somatic MYD88L265P mutation. With a presence of an IgM-paraprotein, he was diagnosed with Waldenström macroglobulinemia (WM) with secondary PRCA and treated with 6 cycles of bendamustine and rituximab. He achieved a complete response with this regimen and was transfusion independent. In this case, underlying WM was uncovered through systematic investigation of anemia caused by ICI therapy. This report highlights the possibility of a lymphoproliferative disorder in patients with concerns for PRCA with prior ICI exposure. If identified, treating the underlying lymphoproliferative disorder is highly efficacious in the management of the secondary PRCA.