Indian Journal of Pathology and Microbiology

: 2020  |  Volume : 63  |  Issue : 1  |  Page : 154--156

Myelomatous ascites: Flow cytometric diagnosis and evolution of phenotype

Jasmita Dass1, Gaurav Dhingra1, Nitin Gupta2, Jyoti Kotwal1,  
1 Department of Hematology, Sir Ganga Ram Hospital, New Delhi, India
2 Department of Clinical Hematology, Sir Ganga Ram Hospital, New Delhi, India

Correspondence Address:
Jasmita Dass
Department of Hematology, Sir Ganga Ram Hospital, New Delhi

How to cite this article:
Dass J, Dhingra G, Gupta N, Kotwal J. Myelomatous ascites: Flow cytometric diagnosis and evolution of phenotype.Indian J Pathol Microbiol 2020;63:154-156

How to cite this URL:
Dass J, Dhingra G, Gupta N, Kotwal J. Myelomatous ascites: Flow cytometric diagnosis and evolution of phenotype. Indian J Pathol Microbiol [serial online] 2020 [cited 2022 Oct 7 ];63:154-156
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Myeloma is a clonal plasma cell (PC) disorder characterized by presence of a monoclonal M band in either serum or urine and is identified clinically with the presence of myeloma defining events/biomarkers of malignancy.[1] Although the use of flow cytometry to identify malignant PCs in myeloma is not included in the diagnostic guidelines, it provides useful information on clonality of malignant PCs and to identify aberrant markers expressed by them. The malignant PCs differ in immunophenotype from normal PCs as they aberrantly express CD56 in 75% cases, CD117 and CD20 in 30% cases each, CD28 in 15–45% cases, and CD27 in 40–50% cases and show a loss of CD19 in 95% cases and CD45 is variably positive.[2],[3] After the advent of proteasome inhibitors like bortezomib and immunomodulatory drugs like lenalidomide, there is now a higher likelihood of achieving complete response.[4] Now the use of flow cytometry is being extensively employed to detect residual disease in the myeloma patients who achieve complete response and are candidates for autologous stem cell transplantation.[5],[6]


A 52-year-old male presented with pain in left flank since 1 month with dyspnea on exertion and decreased urine output for 2 days. On examination, he was pale with no palpable organomegaly. Ultrasonography (USG) abdomen showed mild hepatomegaly. Computed tomography (CT) of the abdomen revealed a mass lesion superior to the left kidney with multiple hypodense lesions in the liver and a punched out lytic lesion in the left iliac bone. Complete blood count showed hemoglobin of 86 g/L, total leucocyte count 7.5 × 109/L, and platelet count 150 × 109/L. Peripheral smear showed rouleaux formation with normocytic normochromic anemia. Serum creatinine was 7.7 mg/dL. Total proteins were 9.5 g/dL with hypoalbuminemia (2.8 g/L), hypergammaglobulinemia (6.7 g/L), and reversal of albumin: globulin ratio. Considering the presence of renal dysfunction and the presence of a lytic lesion, bone marrow was done to exclude myeloma. Bone marrow aspiration (BMA) showed 70% PCs including many immature forms. Bone marrow biopsy showed diffuse sheets of PCs and plasmablasts. Flow cytometric immunophenotyping of the BMA showed ~13.2% PCs. These were clonal for kappa and showed a dim expression of CD56 (31.3%) and CD28 (39.3%). They showed a complete absence of CD19 and most of them were CD45 negative. They lacked CD20 and CD117. There were only 0.3% polyclonal normal PCs. The serum protein electrophoresis showed a monoclonal band in the early gamma region comprising 21.6 g/L which on immunofixation electrophoresis was IgAκ. Free light chain assay showed a markedly elevated κ:λ ratio of 1214.3. Based on all these findings, a diagnosis of symptomatic myeloma was established. Fluorescence in situ hybridization (FISH) of the marrow showed an isolated del13q abnormality. FISH was done by concurrent labeling of PCs by cytoplasmic immunoglobulin light chain and the probes used were for del17p, t(4;14), and t(14;16). To determine the true nature of the suprarenal mass detected on CT scan of the abdomen, USG-guided biopsy was done and showed only PCs. To determine the etiology of renal failure, a biopsy had already been done and showed cast nephropathy with deposition of κ in glomeruli. The patient was started on triple therapy with cyclophosphamide (300 mg/m2), bortezomib (1.3 mg/m2 on days 1, 4, 8, and 11), and dexamethasone (40 mg). To save the renal function, plasmapheresis was performed 5 times and he underwent hemodialysis as required. Urine output improved and creatinine gradually reduced.

After four cycles of therapy, patient presented with worsened renal function and massive ascites. Cytopathology of this ascitic fluid (AF) showed an elevated total count of 598/μL with the presence of 65% PCs. AF was also run in body fluid mode on Sysmex XN (Sysmex, Kobe, Japan), and in addition to ~75% mononuclear cells, it revealed a High fluorescent-Body fluid cell % [HF–BF%] of 109/100 White blood cells [Figure 1]. This HF–BF% parameter corresponds to high fluorescent cells. AF was subjected to immunophenotyping. PCs constituted ~40% of all acquired events. These PCs showed a complete loss of CD56 expression and ~98% were CD28 positive. CD19, CD20, and CD117 continued to be negative. Nearly all PCs retained expression of CD138 and were clonal for kappa. Changes observed in PC immunophenotype were a loss of the adhesion marker CD56 and a positive selection of CD28-positive PCs [Figure 2]. The patient was started on hemodialysis and steroids but could not be salvaged.{Figure 1}{Figure 2}


The patients of myeloma usually present with disease restricted to the marrow or may in addition have bony plasmacytomas. In a large series, only ~3.4% at diagnosis and ~5% patients at relapse have extramedullary disease occurring due to hematogenous spread. Patients presenting with extramedullary disease have high-risk features more frequently and are reported to have a shorter progression-free survival and overall survival. Most frequent site of extramedullary disease is skin and soft tissue at diagnosis while at relapse, hepatic involvement is the most pronounced feature.[7] Another series has reported pleural effusions at the time of relapse.[8] Extramedullary PCs showed a high CD44 expression[8],[9] and moderate CXCR4 expression suggesting that these molecules may be associated with extramedullary disease.[8] Other studies have also reported a loss of CD56 in the extramedullary disease component.[9]

Myelomatous ascites is an uncommon manifestation in myeloma. The patients of POEMS syndrome (polyneuropathy, enlarged internal organs [organomegaly], endocrine disorders, monoclonal protein, and skin changes) present with ascites in ~40% cases, but it is generally due to immune activation and inflammation and not due to PC infiltration in AF.[10] Myelomatous ascites has been described as a rare complication of myeloma. In a series of 351 patients from North India, myelomatous effusions were reported in 11/351 patients and of these, 27%, that is, only 3 patients, presented with myelomatous ascites and these also occurred in combination with pleural effusions. These patients showed a very poor overall survival.[11]

Our patient's PCs showed a complete loss of CD56 and a selection of CD28-positive PCs from the time of diagnosis to the time of myelomatous ascites. A loss of CD56 has been reported previously in myeloma, especially in the extramedullary disease component.[9] CD28 expression in the absence of CD117 was shown to have an adverse prognostic impact in myeloma patients.[12] Our patient had both CD28-positive and largely CD56-negative PCs at the time of diagnosis and this could be a sign of aggressive disease biology as these PCs were enriched at the time of relapse. In addition, a clue to the AF involvement came from the body fluid mode on Sysmex XN counter. The parameter HF–BF% was high and this area in the previous series of counters has been shown to include macrophages, mesothelial cells, PCs, and malignant cells.[13],[14]

Our patient showed an isolated del(13q) abnormality at diagnosis and (13q) abnormality at diagnosis which is an early event in myeloma. This abnormality if present in isolation on FISH studies marks a patient as standard risk myeloma.[15] However, FISH could not be repeated at the time of myelomatous ascites, and therefore, any additional abnormalities could not be documented.

Myelomatous ascites is a rare complication of myeloma and assessment of immunophenotype may be helpful in cases where morphology is less distinctive. Body fluid mode on modern counters may also provide a vital clue for the diagnosis of PC disorders.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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