B-cell lymphomas represent about 90 % of all
non-Hodgkin lymphomas (NHLs). Almost all express pan B-cell antigens including
CD19, CD20, and PAX5. Most patients with NHL present persistent painless
peripheral lymphadenopathy. Staging tests do not include colonoscopy. Here we
present a rare case of synchronous occurrence of a high-grade diffuse large
B-cell lymphoma (DLBCL) initially presenting in a tubular adenoma of the large
bowel and subsequently in the bone marrow.
A 73-year-old woman was referred to our hospital because of
leukopenia (minimum 0.6 × 109/L), anemia
(hemoglobin 83 g/L), dyspnea, and B symptoms. Previously, 27 years
earlier, the patient suffered from a pluriform differentiated mucinous breast
carcinoma (pT3 pN0 M0) treated with radiation (46 Gy high dose) after
mastectomy.
A computed tomography (CT) scan of the abdomen detected few enhanced
para-aortal lymph nodes, and routine laboratory analysis showed elevated values
for lactate dehydrogenase (maximum 2892 U/L), C-reactive protein
(312 mg/L), liver enzymes, ferritin (6334 ng/mL), and CA
12 – 5 (160 U/mL). Colonoscopy revealed a 2-cm
tubular adenomatous sigmoid polyp, which was completely removed by endoscopic
resection ([Fig. 1]).
Fig. 1 Endoscopic view of the
polyp at the rectosigmoid junction. Note the smooth contour of the mildly
protruding lesion as well as the bleeding, which occurred even with gentle
endoscopic manipulation.
Histological examination and appropriate immunohistochemical
staining showed high-grade intraepithelial neoplasia and focal infiltration of
the stroma by highly proliferative lymphoid blasts positive for CD20 and PAX5.
Bone marrow immunocytology displayed a monoclonal B-cell lymphocytosis.
Subsequent bone marrow biopsy revealed an interstitial and diffuse infiltration
by a DLBCL with positivity for CD20, bcl2, and PAX5, negativity for TdT, CD10,
and CD34, and a proliferation index of 80 % (MIB1 staining).
Infiltration by the previously diagnosed breast carcinoma was excluded by
negativity for the pankeratin markers A/E1 – 3 and MNF116.
Finally, molecular genetic analysis detecting the rearrangement of the FR3a
region of the immunoglobulin heavy chain was performed, and identical
monoclonal amplificates of approximately 248 base pairs were detected in both
manifestations, demonstrating malignancy and clonal association of the lymphoma
infiltrates in the adenoma and the bone marrow ([Fig. 2]).
Fig. 2 Histochemical and
molecular genetic analysis of lymphoma infiltrates in: a, c,
e the colonic adenoma; b, d, f bone marrow biopsy.
Lymphoid blast infiltrates in the adenomatous stroma (a,
circle and inset) and the bone marrow (b) are strongly
positive for the B-cell marker CD20 (c and
d) and show proliferation rates
> 80 % with the MIB1 stain (insets c and d). Molecular genetic analysis
detecting the rearrangement of the FR3a region of the immunoglobulin heavy
chain (IgH) demonstrates monoclonal amplificates for both lymphoma infiltrates,
showing monoclonal peaks (e and f) with a so-called slight polyclonal background in the
colonic adenoma (e), representing the reactive
non-neoplastic B-cells in the surrounding tissue.
The ileocecal area and ileum are the regions most frequently
affected by primary small-intestinal and large-intestinal NHL, and most of such
cases are DLBCL [1]
[2]
[3]. Synchronous diagnosis of colorectal malignancy and
lymphoma is rare [4]. Colorectal lymphoma is extremely
infrequent, representing less than 0.5 % of all primary
colorectal neoplasms [5].
B-cell lymphomas should be included in the differential diagnosis of
polypoid lesions in patients suspicious for malignancies. Endoscopy with
complete histological analysis may be important in the diagnosis of high-grade
DLBCL of the lower gastrointestinal tract.
Endoscopy_UCTN_Code_CCL_1AD_2AC
