(P 385) SIMULTANEOUS OCCURRENCE OF MANTLE CELL LYMPHOMA AND LIPOSARCOMA IN THE RETROPERITONEUM

Objective: Simultaneous occurrence of multiple primary malignancies (MPM) is rare, and the occurrence of multiple primary malignancies at the same anatomical location is even more seldom. The presence of MPM may cause severe diagnostic challenges, and treatment considerations. We report on a unique case of Mantle cell lymphoma and well-differentiated liposarcoma located at the same anatomical location in the retroperitoneum.

Methods: We obtained data from the patient’s health journal and the Danish Pathology Registry. The patient provided written, signed informed consent.

Results: Results
A 74-year-old female presented with visual disturbances. Biopsy of the conjunctiva showed a Mantle cell lymphoma. A PET-CT scan was performed for staging of the disease and revealed involvement of lymph nodes, the iliac crest, and the spleen. Furthermore, a large lipomatous retroperitoneal tumor was found at the posterior site of the liver, and adjacent to the 2nd part of the duodenum, and with close proximity to the inferior caval vein. The retroperitoneal tumor existed of different components. Biopsy was performed and showed well-differentiated liposarcoma infiltrated by Mantle cell lymphoma. No dedifferentiated component was found. The patient was discussed at a multidisciplinary meeting, and it was decided that the patient needed urgent treatment for the Mantle cell lymphoma, and surgical resection of the well-differentiated liposarcoma could wait. The patient received 6-month treatment for Mantle cell lymphoma and achieved complete remission. Subsequently surgical resection of a 25 x 30 cm large retroperitoneal tumor including the right adrenal gland was performed. The postoperative course was uncomplicated. After surgery, the patient resumed hematological treatment for Mantle cell lymphoma. At four months follow-up, she was doing fine and without recurrence.

Conclusion: Multiple primary cancers cause diagnostic challenges. Once, the diagnosis is established, a multidsiciplinary meeting is of utmost importance to plan a proper treatment strategy for all malignancies.