Multiple primary tumors: Colorectal carcinoma and non-Hodgkin's lymphoma

Colorectal cancer (CRC) is the third most commonly diagnosed cancer, whereas lymphoma is the sixth leading cause of cancer death, 90% of which corresponds to non-Hodgkin's lymphoma (NHL). The association of these two primary tumors, a solid tumor with an hematological malignancy, is very uncommon.

We report the case of a 47-year-old man who presented with abdominal pain, a right upper quadrant mass and 12 kg of weight loss in 9 months. The computed tomography (CT) showed a large intra-abdominal mass and a wall thickening at the rectosigmoid junction. A colonoscopic biopsy confirmed a colorectal adenocarcinoma and a laparoscopic biopsy of the intraabdominal mass confirmed a diffuse large B-cell NHL. After multidisciplinary discussion it was decided to treat first the NHL with 3 cycles of R-CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone). The patient experienced a good response with a 70% decrease in the intraabdominal mass and a negative PET/CT. Four months after diagnosis an anterior rectal resection was performed. The patient recovered uneventfully and was discharged 5 days after surgery. The patient finally died 20 months after surgery due to disease progression.

The association of CRC and NHL is an extremely rare scenario that represents a great multidisciplinary challenge with respect to treatment due to the scarce literature found on this topic.

When CRC and NHL are present, all the different disease patterns must be considered in a multidisciplinary and patient-oriented fashion, in order to decide the best therapeutic strategy for each individual.