Primary Plasma Cell Leukemia Revealed by a Mandibular Lesion: A Case Report.

Primary plasma cell leukemia (PCL) is a rare and aggressive hematological malignancy exhibiting a circulating plasma cell count exceeding 20% of peripheral blood leukocytes or an absolute plasma cell count >2000/mm3. We report a case of a 37-year-old woman presented to the Department of Hematology with a two-month history of growth inside the oral cavity in the upper jaw and weakness. The physical examination revealed a voluminous mass involving the left side of the maxillary gingiva. The maxillofacial computerized tomography (CT) scan confirmed the presence of a solid tissue mass at the left upper maxilla. A biopsy sample obtained from the lesion showed a plasma cell infiltration. The laboratory findings revealed anemia, renal impairment with high levels of creatinine and calcium. Serum protein electrophoresis found a monoclonal peak at IgG lambda, a high level of lambda free light. The diagnosis was subsequently confirmed by a peripheral-blood smear revealed 25% of plasma cells and bone marrow aspiration with 50% of plasma cell infiltration. Primary plasma-cell leukemia (pPCL) was confirmed. The patient received VTD chemotherapy (bortezomib, thalidomide, and dexamethasone) followed by autologous stem cell transplant (ASCT), which resulted in complete remission. At the six-month follow-up, the patient relapsed with extramedullary multiple lesions under ineffective rescue therapy. Response to frontline treatments may be significant initially but short-lived with a dismal median overall survival below one year. This case report aims to highlight the need for awareness among clinicians of the relevance of examining other associated clinical features of pPCL, given its aggressive course and rapid progress without the therapy.