Retroperitoneal abscess shortly after chemotherapy for lung cancer: A case report.

To the best of our knowledge, the formation of a retroperitoneal abscess due to acute appendicitis shortly after administration of chemotherapy for lung cancer has not been previously reported. This is the case report of a 59-year-old male who was admitted to the Mito Medical Center (Mito, Japan) and diagnosed with lung adenocarcinoma with pleuritis carcinomatosis. Although no distant metastasis was identified, combination chemotherapy with cisplatin and pemetrexed was administered. Nine days after initiating chemotherapy, the patient developed right lower quadrant abdominal pain and high fever. Computed tomography (CT) of the abdomen and pelvis revealed the collection of gas and fluid in the retroperitoneum adjacent to the cecum. The abscess was locally drained; however, the infection continued to spread, with subsequent development of a scrotal abscess. Consequently, appendectomy was performed. The patient recovered well and the lung adenocarcinoma was treated with additional courses of chemotherapy following the remission of the local inflammation. Retroperitoneal abscess due to acute appendicitis is an unusual finding; however, this rare complication should be considered during or shortly after chemotherapy in patients with lung cancer.