A case of perforated appendicitis during temsirolimus treatment for metastatic renal cell carcinoma

Temsirolimus is a novel inhibitor of the mammalian target of rapamycin (mTOR) and is approved for the treatment of metastatic renal cell carcinoma (RCC). mTOR has become an important therapeutic target for advanced RCC. We present a case of mTOR inhibitor-associated perforated appendicitis. The patient was a 49-year-old man with advanced RCC. Radical nephrectomy was performed after 17 courses of sunitinib. After the surgery, sunitinib therapy was continued to treat the metastatic RCC. Sunitinib was switched to temsirolimus because radiologic progression was observed. After three courses of temsirolimus treatment, the patient developed right lower quadrant abdominal pain. CT scan showed perforated appendicitis and a periappendiceal abscess. He received outpatient antibiotic therapy as initial treatment for the perforated appendicitis. Fortunately, the appendicitis could be cured without any surgical intervention. Subsequently, sunitinib administration was restarted (25 mg daily for 4 weeks followed by a 2 weeks break). The disease was stable after 29 treatment cycles.