Unveiling the Enigma: Plasma Cell Leukaemia Presenting with Flower-like Cells, Mimicking Adult T-cell Leukaemia - A Rare Diagnostic Conundrum.

Peripheral plasma cell leukaemia (PCL) is a rare hematologic malignancy that can pose diagnostic challenges due to its resemblance to other conditions such as adult T-cell leukaemia/lymphoma (ATLL) or dissemination lymphoma in peripheral blood. We present a case report of a 40-year-old male with symptoms of fatigue, irregular heartbeat, weight loss, and bone pain, whose peripheral blood examination revealed hyperleukocytosis with atypical lymphoid cells exhibiting flower-shaped nuclei, reminiscent of adult T-cell leukaemia/lymphoma. Further investigations including bone marrow aspiration and biopsy confirmed the diagnosis of primary PCL. Immunophenotyping revealed expression of plasma cell antigens CD38 and CD138. This case underscores the importance of recognizing morphological variants and employing comprehensive immunophenotypic analysis for accurate diagnosis of PCL, especially when atypical nuclear features mimic other hematologic malignancies.