The authors have declared that no competing interests exist.
This report presents a case of collision tumors of low-grade B-cell lymphoma and poorly differentiated adenocarcinoma in the caceum of a 63-year-old woman. Lymphoma was diagnosed incidentally after appendectomy for a clinical presentation of acute appendicitis. Imaging follow-up demonstrated mesenteric lymphadenopathy and liver lesions, and all surgically resected regional mesenteric lymph nodes and liver biopsy were found to be infiltrated by both mucosa-associated lymphoid tissue (MALT) lymphoma and adenocarcinoma. Systemic chemotherapy was administered for advanced colonic adenocarcinoma with liver metastases. The occurrence of synchronous lymphoma and adenocarcinoma of the colorectal region is rare, and this is a previously unreported case of a patient that was diagnosed during management of acute appendicitis.
Collision tumors of lymphoma and colorectal adenocarcinoma are rare entities and just a few studies exist
A 63-year-old woman presented to the Department of General Surgery as an outpatient with abdominal pain. Physical examination showed the signs of acute appendicitis and appendectomy was performed. During microscopic examination, a small focus of atypical monotonous lymphoid cell population was seen and the material was sampled totally. The pathological examination revealed MALT lymphoma (
Second malignancies are classified as synchronous or metachronous. According to Gluckman’s definition, “synchronous carcinomas” include carcinomas that present either simultaneously or within a six-month period of identification of the original tumor
The gastrointestinal tract is the most frequently involved extranodal site in non-Hodgkin lymphoma, with stomach being the most common (50%-60%) followed by the small intestine (30%)
Mucosa-associated lymphoid tissue MALT tumors are a distinct subtype of non-Hodgkin’s lymphoma associated with predisposing infectious or autoimmune processes, resulting in chronic lymphoid proliferation. Though the stomach is the most common site, MALT tumor has been reported in non-gastric sites like salivary gland, lung, eyes, adnexa, and skin. The colon is a rare location for MALT lymphoma
Synchronous mantle cell lymphoma and adenocarcinoma (5 cases) were the most frequent diagnoses followed by synchronous extranodal marginal zone lymphoma of MALT and adenocarcinoma (3 cases). The involved sections of the colon included the caecum, ascending colon, sigmoid colon and rectum. Nearly all cases were preoperatively diagnosed as colonic adenocarcinoma. This indicates that it is a challenge to recognize synchronous colonic adenocarcinoma and malignant lymphoma preoperatively
Several case details of colonic synchronous mantle cell lymphoma and adenocarcinoma were reported in the literature, but to the best of our knowledge upon review of literature the present case is the first which was diagnosed firstly as lymphoma incidentally within the appendectomy specimen with synchronous adenocarcinoma and lymphoma in the colonic resection specimens. One of the features that distinguishes our case from the other cases was lymphoma infiltration of metastatic lymph nodes and the other was the presence of adenocarcinoma metastasis in liver parenchyma with lymphoma infiltration in the portal tracts.
There are some hypotheses suggesting the etiology of collision tumors. One hypothesis is that the two primary tumors arise in continuity through a chance accidental ‘meeting’. Another hypothesis is that the presence of the first tumor alters the microenvironment, precipitating the development of the second adjacent tumor
Chance coincidence is favored. However, local factors such as absent immune surveillance in the lymphoma which possibly allow carcinoma cells to grow has also been suggested. The association between gastric MALT lymphoma and chronic
In conclusion, coexisting primary malignant lymphoma and colonic adenocarcinoma in one patient is a very rare event. Pathologists should be aware of the existence of synchronous tumors in the small and large intestines. Chance coincidence or poor immunity in patients may contribute to the etiology, but further research is required to determine the true underlying etiology of these cases.