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Diagnosis of chronic lymphoproliferative disorder on February 2009 with presence of 14q32 IgH rearrangement by FISH analysis on blood sample with no partner identified (CCND1, BCL2 and BCL3 excluded). No treatment.

64 yrs

M

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+ occurence of an organomegaly on January 2011 with diaphragmatic lymph nodes and tonsil infiltration

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14,6

14,2

212

with 65% polynuclear neutrophils, 27% lymphocytes and 8% monocytes. 45% of the lymphocytes present a typical morphology of prolymphocytes with enlarged and basophilic cytoplasm and presence of a unique, prominent nucleolus.

Prolymphocytic leukaemia

CD19+, CD5+(high),CD23+(low), CD22+(high), CD79b+(high), FMC7+, surface Ig Lambda (high). Matutes score = 2 (CD10-, CD20+ high, CD43-, CD81+ high)

not done

Large infiltration of the tonsil by a monomorphic B-cell lymphoma with a diffuse growth pattern composed of small to medium-sized cells positive for CD5, compatible with the diagnosis of mantle cell lymphoma, but without expression of cycline D1.

not done

B cell prolymphocytic leukaemia

02-2009 (flow cytometry and FISH analysis) First conventionnal cytogenetic analysis performed on 01-2011.

none to date

none

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N/A

A

02-2011

Blood sample

72 with DSP30+IL2

RHG

46,XY,t(3;17)(q26;q12),t(8;14)(q24;q32)[20]

FISH analysis using MYC break apart (Abbott-5J9101) and IgH break apart (Abbott-5J7301) probes on blood sample : confirmation of MYC and IgH rearrangements on respectively 89 and 90% of the cells. FISH analysis on tonsil sample : confirmation of MYC and IgH rearrangements on respectively 80 and 73% of the cells.

Complementary FISH analysis on initial blood sample (02-2009): - using MYC Break apart probe : presence of MYC rearrangement in 94% of the cells; - using CLL probe set (Abbott-8L5320) : no deletion 17p, no deletion 11q, no trisomy12, no deletion 13q.

MYC rearrangement in chronic lymphocytic disorder is a very rare event (<1 % of CLL) (Lu et al., 2010). The presence of the t(8;14) translocation is preferentially associated with increased prolymphocytes (Huh et al., 2008; Merchant et al., 2003), and, indeed, is described as a recurrent abnormality in B cell prolymphocytic leukaemia (Merchant et al., 2003; Kuriakose et al., 2004; Crisostomo et al., 2007). In the case reported here, two years after the description of 14q32-IgH rearrangement on blood sample, the discovery of a t(8;14) by conventional karyotype was an important clue for the orientation of the diagnosis after reviewing cytologic and immunophenotypic data. In addition, these data lead to reconsider also the initial histopathologic hypothesis of mantle cell lymphoma all the more as no t(11;14) translocation as well as non hyperexpression of cycline D1 were present. Identification of a B cell prolymphocytic leukaemia is essential because of the potential rapid evolution with rising of leucocytes count and the poor response to CLL therapies (Swerdlow et al., 2008).