Primary plasma cell leukaemia presenting with flower‐shaped nuclei

Abstract

A 64-year-old man presented with a persistent cough. His past medical history included COVID-19 pneumonia one month previously. On admission, a full blood count showed a haemoglobin concentration of 120 g/l, a platelet count of 98 9 10 9 /l and a leukocyte count of 44 9 10 9 /l. A peripheral blood film showed 80% atypical lymphoid cells. Many of the abnormal cells had deeply basophilic cytoplasm with a markedly irregular nuclear contour producing a petal-shaped nucleus, mimicking the flower cells of adult T-cell leukaemia/lymphoma (ATLL) (all images; May-Gr€ unwald-Giemsa stain, 9100 objective), while other atypical cells showed either bilobed or rounded nuclei.Flow cytometric analysis showed strong expression of CD38, CD56 and CD138 with no expression of CD3, CD4, CD7, CD8, CD19, CD20, CD25 or CD45. Serum calcium was normal. Serum protein electrophoresis and immunofixation showed a lambda monoclonal component (12 g/l) with lambda-free light chains being quantified at 42.9 g/l. Antibodies to the human T-cell lymphotropic virus-1 (HTLV-1) were not detected. A diagnosis of primary plasma cell leukaemia was made.A bone marrow aspirate film was hypercellular with 95% abnormal plasma cells. Cytogenetic analysis showed a complex karyotype: 42,X,ÀY,add(1)(q?),+del(1)(p21),del(2) (q32),À5,À10,del(11)(q23),À12,À13,add(14)(q32) [16]/46,XY [9]. Fluorescence in situ hybridisation (FISH) analysis showed deletion of RB1 and LAMP1 on 13q, t(4;14) (IGH/ FGFR3 rearrangement) and amp(1q21).Plasma cell leukaemia rarely presents with flower-shaped nuclei. A differential diagnosis of ATLL should be considered in these cases, especially in HTLV-1 endemic areas.

Caution the Difference Between the Flower-like Lymphocyte with Flower-like Plasma Cell

“…These authors reported a case of multiple myeloma showing abnormal plasma cells with flower-shaped nuclear features. These cells with flower-shaped nuclei have also been reported in cases of plasma cell leukemia in previous studies [ 2 , 3 , 4 , 5 ]. The authors described the morphological features of flower-like cells in order to help pathologists identify them for diagnostic purposes.…”

Flower-like Plasma cell: a Comment

“…These morphological features can pose a diagnostic dilemma and can mimic lymphoma as “flower cells” or clover-leaf lymphocytes are described typically in HTLV-1-induced adult T-cell leukemia and very rarely in B-cell lymphoma [ 2 ]. Plasma cell myeloma or leukemia rarely presents with flower‐shaped nuclei and occasional cases of plasma cell leukemia mimicking adult T-cell leukemia/lymphoma were previously reported in the literature [ 3 , 4 ]. Upon flowcytometric immunophenotyping, the absence of B-cell or T-cell markers and the presence of plasma cell markers with strong CD38 and CD138 help in differentiating it from lymphoma.…”

Primary plasma cell leukemia presented with atypical flower‐like morphology

“…Typical morphology in primary plasma cell leukemia (pPCL) usually resembles small mature plasma cells. However, diagnosis is sometimes challenging, as most of neoplastic cells present irregular, multilobulated or petal‐shaped nuclei 1,2 . Clear identification of these unusual morphological variants is important to avoid misdiagnosis of adult T‐cell leukemia/lymphoma, reactive monocytes in viral infection, seldom B‐cell lymphoma 1 .…”

“…Usually it occurs in younger patients, has a more aggressive course and poor outcome 3 . Occasionally, its morphological appearance poses a diagnostic dilemma mimicking flower‐cells 1,2 …”

“…However, diagnosis is sometimes challenging, as most of neoplastic cells present irregular, multilobulated or petal-shaped nuclei. 1,2 Clear identification of these unusual morphological variants is important to avoid misdiagnosis of adult T-cell leukemia/lymphoma, reactive monocytes in viral infection, seldom B-cell lymphoma. 1 This paper presents a rare case of pPCL with atypical flower-like morphology.…”