LABORATORY DATA
Hemogram: WBC 2.1 K/ul, RBC 3.93 M/ul, HGB 12.6 g/dl, HCT 36.9 %, MCV 93.7 Fl, MCH 32.0 pg, MCHC 34.1 g/dl, RDW 16.6%, PLT CNT 131 K/ul DIFF: GRAN 55%, LYMPH 39%, MONO 5%, EO 1%, BASO 0%

ANCILLARY STUDIES

Cytochemistry
Peripheral blood lymphocytes (Figure 1) show TRAP (Tartrate-resistant acid phosphatase) positivity. A neutrophil in the same field is TRAP-negative.

Immunohistochemistry
Markedly increased numbers of CD20-positive B-cells. DBA.44 immunostain shows similar findings (Figure 2).

Figure 1:	Figure 2:

Flow Cytometry
A monoclonal B-cell population is identified by gating on cells with slightly higher side scatter than normal lymphocytes. CD22-positive B-cells display bright coexpression of CD11c. Coexpression of CD25 and CD103 is present along with lambda light chain restriction. (Figures 3, 4, 5, 6)

Figure 3:	Figure 4:	Figure 5:	Figure 6:

Electron Microscopy
EM (Figure 7) was not performed on this particular case, but about 50% of cases will show ribosome-lamellar complexes.

GROSS PATHOLOGY
Gross Features: bone marrow biopsy and aspirate from right posterior iliac crest.

Figure 7:	Figure 8:	Figure 9:	Figure 10:

MICROSCOPIC PATHOLOGY
Peripheral blood lymphocytes (Figure 8 ) are intermediate in size with relatively abundant, pale cytoplasm and irregular cytoplasmic borders. The nuclei are lobulated and appear monocytoid/reniform with reticular chromatin (Figure 9). Low-power view of hypocellular bone marrow (Figure 10). Increased numbers of lymphocytes in an interstitial pattern. Erythroid and myeloid hypoplasia.