Plasma cell leukemia in a 34-year-old male: rare scenario case report.

Introduction: Plasma cell leukaemia is an uncommon plasma cell dyscrasia with a very poor prognosis. It is more common among males and usually presents between 55 and 65 years of age. Case presentation: A 34-year-old male presented to Al-Assad hospital with unremitting back pain. He was given analgesics but his pain was unresponsive to treatment, and due to the COVID-19 pandemic, he refused a computed tomography scan in the hospital. Later that year, he presented again with weight loss, nausea, abdominal pain, melena, and ascites. He was pale with a moderately distended abdomen. Laboratory tests revealed anaemia, thrombocytopenia, hypercalcemia, increased total proteins, and elevated lactate dehydrogenase. Flow cytometry findings of the bone marrow aspirate showed the presence of 30% of plasma cells, positive for CD38, CD56, and kappa light chains. He was diagnosed with secondary plasma cell leukaemia and started on chemotherapy; however, he could not continue his treatment due to myeloid inhibition. He passed away 5 months later. Clinical discussion: Multiple myeloma was not suspected in the patient due to his young age. The diagnosis was delayed even further due to the COVID-19 pandemic. His multiple myeloma progressed into secondary plasma cell leukaemia and had uncommon features like small intestinal polyps. Even though there has been groundbreaking advancements in chemotherapy, plasma cell leukaemia still possesses a fatal prognosis. Conclusion: This report showcases a rare age presentation with unique manifestations of secondary plasma cell leukaemia. Multiple myeloma should be a differential diagnosis for cases with unexplained back pain despite an unclassical age.