Low-grade rectal malt lymphoma occurring in a patient with chronic lymphocytic leukaemia


We read with great interest the correspondence from Dr Aguilar (2000), which reported a case of gastric mucosa-associated lymphoid tissue (MALT)-non-Hodgkin's lymphoma (NHL) as a second malignancy in chronic lymphocytic leukaemia (CLL). We report another unusual case of rectal low-grade MALT-NHL, occurring in a patient with CLL.

In January 1999, B-CLL, Binet stage A, was diagnosed in a 42-year-old woman. The monoclonal B cells exhibited the typical phenotypic markers (CD5+, CD19+, CD23+). It was decided to follow a ‘watch-and-wait’ policy in this case and, in October 2000, the patient presented with fever and night sweats. The peripheral blood cell count analysis showed a greater than 50% increase in the number of lymphocytes over a 2 month period. The patient also reported abdominal pain, tenesmus and rectal bleeding. Endoscopic examination showed a tumoral and infiltrated aspect of the rectal mucosae with haemorrhagic suffusions. Pathological and phenotypic features led to the diagnosis of MALT-NHL, characterized by a nodular proliferation of small B cells (CD5, CD43, Bcl-2+) invading the rectal mucosae (Fig 1) and by the presence of lympho–epithelial lesions. No CLL infiltrate was present. Bone marrow biopsy showed a diffuse infiltrate by CLL. A computerized tomography scan of the whole body showed disseminated enlarged nodes and splenomegaly. Upper gastrointestinal endoscopy was normal and systematic biopsies analyses were free of Helicobacter pylori. The search for serum anti-Helicobacter pylori antibody was negative. The patient received four cycles of chemotherapy with fludarabine and cyclophosphamide, resulting in a complete response for both CLL and MALT-NHL.

Figure 1.

Nodular proliferation of small B cells (CD5–, CD43–, Bcl-2+) invading the rectal mucosae without CLL infiltrate. Haematoxylin–eosin stain, original magnification ×25.

Epidemiological studies have clearly demonstrated a significant increased risk of second cancers in CLL patients (Mauro et al, 1999). The putative role of chemotherapy, such as alkylating agents, can be raised in the development of second cancers. However, second neoplasms have also been reported in patients with CLL and free of treatment. The development of aggressive NHL in the course of CLL is well known. In contrast, very few cases of CLL patients who develop secondary indolent lymphomas have been reported. Among the low-grade NHLs, the MALT entity is unique in its association with Helicobacter pylori. The co-existence of B-CLL and MALT-NHL in the same patient is exceptional. To our knowledge, only two patients associating CLL and MALT-NHL have been reported in the literature (Au et al, 1999; Aguilar, 2000). The first case concerned a 72-year-old woman with a smouldering B-CLL who did not require any treatment (Aguilar, 2000). She developed a gastric MALT-NHL 16 years after the diagnosis of CLL and was cured using Helicobacter pylori eradication treatment. The second patient was less typical. This patient was reported in a retrospective study, which estimated the incidence of second neoplasms in patients with MALT-NHL. The 70-year-old man developed a skin MALT-NHL 9 years after the diagnosis of CLL (Au et al, 1999). The rectal localization of MALT-NHL observed in our patient is rare, as very few observations have been reported (Orita et al, 1999). Our observation of both B-CLL and MALT-NHL occurring in the same patient appears closely related to the one reported by Aguilar (2000). In both patients, MALT-NHL was localized in the gastro-intestinal tract. Such an association could be possibly a coincidence. However, both CLL and MALT-NHL are lymphoproliferative diseases involving mature B cells, and it has been demonstrated that both MALT and CLL cells can harbour somatic mutations of immunoglobulins genes, thereby suggesting a close differentiation stage in at least some patients. However, the phenotypic markers routinely used are specific enough to easily separate CLL from MALT-NHL. In summary, our observation confirms the possible co-existence of both B-CLL and MALT-NHL. The appropriate therapy for these patients needs to be determined in a larger series of cases.