Incidental lymphoma in lymph node dissection for carcinoma in the abdominopelvic cavity: a single-institution experience.

Incidental detection of lymphoma in lymph node (LN) dissection for carcinoma is extremely rare. The occurrence and clinicopathological features of this rare condition have not been characterised. The medical records of 11,889 consecutive patients who underwent LN dissection for carcinoma in the abdominopelvic cavity were retrospectively reviewed. Among these patients, 11 had lymphomas detected in LN dissections and 7 had no previous history of lymphoma, representing an incidental detection rate of 0.06% (7/11889). The patients had a median age of 63 years (range, 48-69 years), and the male-to-female ratio was 1:2.5. The sites and histological types of the carcinoma were as follows: adenocarcinoma of the sigmoid colon (2 cases), endometrioid adenocarcinoma of the endometrium (2 cases), squamous carcinoma of the uterine cervix (1 case), adenocarcinoma of the stomach (1 case), and adenocarcinoma of the rectum (1 case). All incidental lymphoma cases (100%, 7/7) were low-grade B cell non-Hodgkin lymphoma (B-NHL), including 5 cases of follicular lymphoma (grades 1-2) and 2 cases of small lymphocytic lymphoma. The median follow-up interval was 39 months (5-65 months). All the patients were alive at the end of the follow-up period. Low-grade B-NHL can be incidentally detected during LN dissection for carcinoma in the abdominopelvic cavity. The subtype of incidental lymphoma is likely related to the epidemiology of lymphoma classes in the corresponding area. We should be aware of simultaneous occurrence of incidental lymphoma during lymphadenectomy for carcinoma.