ALK-positive anaplastic large cell lymphoma presenting multiple lymphomatous polyposis: A case report and literature review

BACKGROUND Anaplastic large cell lymphoma (ALCL) is a type of T-cell lymphoma that can be divided into two categories: anaplastic lymphoma kinase-positive (ALK+) and ALK-negative. Gastrointestinal ALK+ ALCL is rare. Multiple lymphomatous polyposis (MLP) is thought to be a representative form of gastrointestinal lesion in mantle cell lymphoma, and T-cell lymphomas seldom show this feature. Here, we report the first known case of ALK+ ALCL with gastroduodenal involvement to present with MLP. CASE SUMMARY The patient was a 43-year-old man who was complained of a mass in the left inguinal area and was performed open biopsy. ALK+ ALCL was diagnosed pathologically. Computed tomography scan demonstrated multiple lymph node lesions in the abdomen - pelvis/inguinal region, and scattered nodular lesions in both lung fields. He did not complain of gastrointestinal symptoms. While, esophagogastroduodenoscopy identified MLP lesions from the antrum of the stomach to the descending portion of the duodenum and mild thickened folds on the corpus of the stomach, and biopsy showed invasion of ALK+ ALCL. We treated this patient with six cycles of CHOEP (Cyclophosphamide, Doxorubicin, Vincristine, Etoposide, and Prednisone) chemotherapy. At the conclusion of treatment, there was complete remission. Numerous white scars were found on the stomach, endoscopically consistent with a remission image of lymphoma. The endoscopic features of this case were thought to be similar to those of MCL. CONCLUSION The macroscopic/endoscopic features of gastrointestinal ALK+ ALCL may be more similar to those of B-cell lymphomas rather than T-cell lymphomas.