Primary large bowel lymphomas account for approximately 0.2% of all large bowel malignancies.1
The term MALT lymphoma was coined by Isaacson and Wright2
and is considered as extra-nodal equivalent of B cell lymphoma. The extra-nodal involvement has been found to include organs such as the stomach, thyroid and salivary glands.3 4
Involvement of the colon and rectum is extremely uncommon. Less than 25 cases have been reported in the literature so far.
MALT tumours appear to have similar clinical, pathological and molecular features regardless of organ of origin. There is some evidence to link Helicobacter pylori
infection to gastric MALT lymphoma and H pylori
eradication treatment has been suggested for low-grade gastric MALT lymphoma.5 6
However the consensus is not uniform. It has also been suggested that colorectal MALT lymphoma may have a similar pathophysiology.7
This has led some to hypothesise that by treating H pylori
, one may inadvertently treat MALT lymphoma in the rectum. A case of complete regression of a rectal MALT lymphoma has been reported in a patient after a course of levofloxacin although H pylori
infection persisted after cessation of treatment.8
A spontaneous regression of MALT lymphoma in an unfit patient has also been reported.9
As the occurrence of colorectal MALT lymphoma is rare, research-based evidence is still lacking in regards to best management options. A variety of treatment options, including surgery,10
or a combination have been recommended. Surgery offers the additional benefit of histological diagnosis and other important prognostic information.
Prognostic factors include tumour stage, nodal status and possibly genetic contribution. For example, a mutation in the P53
gene has been reported to contribute towards development of MALT lymphoma.15
Ashton-Key et al
suggested stable expression of bcl-2
gene to be a contributory factor for the good prognosis seen in MALT lymphoma.14
In our report, we advocate the use of surgery in a medically fit patient—a choice recommended by others.10
A multidisciplinary input is recommended. Our patient did not receive any eradication treatment preoperatively owing to lack of firm evidence. A long-term follow-up of different treatment modalities is needed in order to establish the most suitable approach. Further understanding of the role of H pylori
in the pathophysiology of rectal MALT lymphoma is needed.
- Our report highlights an interesting and rare case of a solitary rectal MALT lymphoma treated successfully by surgical resection and radiotherapy.
- The report highlights an unusual presentation of gastrointestinal lymphoma and one should be aware of this possibility when dealing with large bowel pathology.
- As yet there are no gold standards, treatment options must be discussed with the patient.
- The role of H pylori is of interest and, if proven, may lead to future medical treatments becoming available.