[Utility of core-needle biopsy as a primary diagnostic method for detecting aggressive B-cell lymphoma in the intensive care unit].

A 68-year-old male presented with appetite loss and abdominal distention. The whole-body computed tomography scan revealed an ileocecal mass with a large amount of ascites, which was consistent with malignant lymphoma. Due to the worsening of his general condition following admission, he was intubated and admitted to the intensive care unit (ICU). In the ICU, we performed a core-needle biopsy (CNB) on the left peritoneal mass, the findings of which showed a pathological diffuse infiltration of CD20+ middle-sized lymphoid cells. After chemotherapy was initiated, the patient showed complete response, suggesting that CNB can be performed immediately and safely even on a critically ill patient.