An Inflammatory Myofibroblastic Tumor of the Bladder in a 12-Year-Old Male

Abstract

A 12-year-old male was referred to our hospital because of phallodynia. Ultrasound echo demonstrated a 30 mm tumor at the left wall of the bladder. He has no medical history, and we performed open biopsy. Because pathological diagnosis of the tumor was rhabdomyosarcoma, we started VAC therapy. However, the tumor size increased, and it was judged to be resistant to chemotherapy. After two courses of chemotherapy, the tumor was completely removed. Finally, it was diagnosed as inflammatory myofibroblastic tumor (IMT) because fibroblasts increased in number neoplastically and pathological examination revealed anaplastic lymphoma kinase (ALK)-positive findings. Fourteen months have elapsed since the operation, and no sign of recurrence or metastasis has been observed. IMT is a rare disease with the proliferation of myofibroblasts and infiltration of inflammatory cells. The pattern of infiltration varies; therefore, it is often difficult to differentiate inflammatory disease from malignant tumor. The recommended treatment is complete resection; if so, the prognosis is good. Careful long-term postoperative observation is important, because there are a few cases of tumor recurrence.