Neuromyxomas Neuromyxomas are a group of tumors consisting of muscle and nerve tissue. This is a malignant neoplasm, which is characterized by rapid growth and the ability to metastasize (spread throughout the body). Neuromyxoma can lead to a variety of conditions, such as pain, neurological problems, a tumor in the chest or abdomen, and ascites (a buildup of fluid in the abdomen). There are various causes of neuromyxomas. These include nerve damage, infectious diseases and radiation exposure. Unfortunately, neuromyxomas are very rare, making their diagnosis and treatment difficult. Diagnosis consists of visual examination, ultrasound, computed tomography and tumor tissue biopsy. Treatment for neuromyxomas must be aggressive and may include surgical removal of the tumor, chemotherapy and/or radiation therapy.