Abstract
A 74-year-old man seen elsewhere for positive occult blood in the stool detected during a municipal health examination was suspected from lower gastrointestinal endoscopy of having malignant lymphoma of the ascending colon and referred to us. Physical examination showed no superficial lymph nodes to be palpable, but barium enema and lower gastrointestinal endoscopy showed a type 1 tumor 2 cm in diameter in the ascending colon. Immunohistochemical staining of biopsy specimens yielded a diagnosis of extramedullary plasmacytoma. Fluorodeoxy glucose positron emission tomography (FDG-PET) showed marked accumulated FDG in the lesion but no evidence of metastasis, necessitating laparoscopic ileocecal resection with D2 lymph node dissection. The histopathology of the resected tumor showed diffuse proliferation of plasma cells producing κ chains, with an intramural invasion to the muscularis mucosae. No lymph node metastasis was found. At 18 months after surgery, the man shows no evidence of metastasis or relapse and is being treated as an outpatient. Extramedullary plasmacytomas originating in the large intestine are extremely rare; with only 5 patients, including ours, having been reported in Japan. Our patient is also considered as the first case of extramedullary plasmacytoma reported anywhere in the world to have been treated by laparoscopic ileocecal resection. This case is discussed with reference to the literature.
