Lymphoepithelioma-like
carcinomas (LELCs), especially
colorectal cancers (
CRCs), are uncommon pathological phenotypes generally associated with poor aggressiveness and a preferable prognosis. However, PD-L1 overexpression in
CRCs is associated with poor outcomes. We report a case of moderately differentiated
adenocarcinoma with PD-L1 overexpression, an LELC component, and Crohn's-like lymphoid reaction (CLR) presenting with extreme locoregional aggression and complete remission with
chemotherapy after noncurative excision.
CASE PRESENTATION: A 69-year-old man was referred to our hospital for abdominal fullness and
pain. Computed tomography (CT) showed a circumferential
tumor in the ascending colon, accompanied by bulky swollen lymph nodes. Under the preoperative diagnosis of T4N2M1 (lymph nodes) ascending colon
cancer, we performed a right
hemicolectomy; however, paracaval and parailiac vein lymph nodes were abandoned. Pathological findings showed moderate to poorly differentiated
adenocarcinoma invading the subserosa accompanied by an LELC component invading the superficial muscularis propria.
Lymph node metastases were found in a neighboring
tumor and in retroperitoneal lymph nodes with glandular differentiation. No relation to
microsatellite instability (MSI) or Epstein-Barr virus (EBV) was observed. In the component with glandular differentiation, PD-L1 overexpression was revealed. CLR findings were also observed. The
tumor was diagnosed as T3N2M1
cancer that was moderately to poorly differentiated and had an LELC component. The patient was treated with
chemotherapy, and the metastasized lymph nodes ultimately disappeared. He was alive without
tumor recurrence 5-years post-operation.
CONCLUSION: This is a very rare case of moderately differentiated
adenocarcinoma with PD-L1 overexpression and a heterogeneous LELC component that developed in the ascending colon. Unlike the previously reported weak aggressive properties of LELCs, the present case showed an extremely aggressive locoregional extent, but complete remission was finally achieved with
chemotherapy. This type of LELC with CLR could be associated with a good response to
chemotherapy and a good prognosis in CRC patients.