Rhabdomyosarcoma (RMS or Rhabdo) is an aggressive and highly malignant form of cancer that forms in the soft tissues. It can occur anywhere in the body but is most generally found in the structures of the head and neck, the urogenital tract, and the arms or legs but can also form in parts of the body without muscle, such as the bile duct, the prostate, or along the meninges, the membranes that line the skull and vertebral canal. While generally thought of as a childhood disease—a majority of cases are found in children and young adults—it is not uncommon to find in teenage and adult patients as well.

Rhabdomyosarcoma is considered a rare cancer—with roughly 350 cases diagnosed in the US each year—although it is the most common soft-tissue sarcoma in children and adolescents under the age of 20. With so few cases to be seen, it is unusual for any pediatrician or primary care physician to see one, let alone a number of patients with this disease. This can delay accurate diagnosis which is so very important with this disease.

Types of Rhabdo

Rhabdomyosarcoma can occur throughout childhood and may even be present at birth. It is a rare form of cancer but a further complication is that there are multiple sub-types, although the first two are the most prevalent.

• Embryonal: This type occurs most often in the head and neck area or in the genital or urinary organs. It is most often seen in children under the age of 5.

• Alveolar: This type occurs most often in the arms or legs, chest, abdomen, genital organs, or anal area. While it occurs in all age groups, it usually occurs during the teen years.

• Botryoid: A sub-type of embryonal Rhabdo, botryoid tumors arise under the mucosal surface of body orifices such as the vagina, bladder, nasopharynx and biliary tract. They represent approximately 10% of all rhabdo cases.

• Spindle Cell: Another sub-type of embryonal rhabdo, spindle cell tumors typically found in young males and most commonly involves the paratesticular region followed by the head and neck.

• Sclerosing: This is a newly recognized form of Rhabdo and can occur in both children and adults. Many of the qualities of Sclerosing Rhabdo overlap those of Spindle Cell and the two are often combined and classified as “spindle cell/sclerosing RMS.”

• Anaplastic (Pleomorphic): Is an uncommon form of Rhabdo that occurs in adults but is very rare in children.
  
  

Rhabdo Presentation

Not only is Rhabdo a rare disease, but it presents itself differently in almost every case. For example:

• A Mosquito Bite? — A first grader was being bathed by her father who noticed a small bump on her leg. It looked very much like a mosquito bite but it wasn’t mosquito season and something just ‘didn’t look right.’ He took her to the pediatrician, who could have easily said, ‘looks like a bug bite, let’s wait a few days to see what happens.’ But instead said that he was going to do an ultrasound and if he saw anything unusual, she was going to be sent for an immediate biopsy. The small, mosquito bite like bump was the very end of a tumor that grew the entire length of her calf muscle before it began to move outward.

• A Stomach Bug? — A pre-schooler with headaches that only seemed to be relieved after he vomited. Pediatrician noted that the same thing happened 4 times in the past month, that the vomit was ‘foamy’ and not food, and recorded that the child’s temperature was normal. After a number of similar visits, the child was given a prescription for a medication that is designed to treat certain stomach and esophagus problems (such as acid reflux, ulcers). The headaches and vomiting continued for over a month at which time the pediatrician’s office recommended that he be brought to a children’s hospital. A CT scan indicated a diagnosis of hydrocephalus. He was then given an MRI which showed the presence of diffuse tumor along the meninges, consistent with a possible medulloblastoma or lymphoma. A surgical biopsy revealed that the tumor was Embryonal Rhabdomyosarcoma.

• A Varicocele? — A college freshman discovered that he had a lump on his testicle. After an examination by a urologist, he was told that it was possibly a varicocele (a conglomeration of veins that occur in the testicles) and that he should watch it for about three months and if it didn’t change, not to worry. A month later, he thought it was getting bigger and returned to the urologist who said they could go in and look to see if there is something of concern. The surgical report indicated that is was indeed a varicocele and a hydrocele (fluid buildup) and that the fluid was drained but they did not want to touch the varicocele for fear it would affect his ability to reproduce. Two months later, he came home on Christmas break and was complaining about pains in his upper back. Being an athlete, he thought it was just a sprained muscle and let it go. Back at school, the pain wasn’t getting any better and the doctor prescribed anti-inflammatory meds and sent him back to his studies. After a few weeks on these meds, and the pain was not getting any better, he went back to the doctor who then prescribed acid reflux medication. Eight months after the initial varicocele diagnosis, and five months after the complaints of upper back pain, he was diagnosed with Stage 4 Alveolar Rhabdomyosarcoma. It turns out that the primary site was the testicle and at this time the cancer had metastasized to his lymph nodes and bone marrow.

• Constipation? — After numerous days of not being able to go to the bathroom, the toddler was taken to the doctor’s office and examined by a Physician’s Assistant (PA) who recommended that she be given a laxative twice a day until she was going a significant amount on a regular basis. Even increasing the dosage of the laxative, nothing was moving. Three weeks after seeing the PA, she vomited from her nose and mouth and her parents noticed a bulge near her belly button. An ultrasound was done and the tech noted that she had a full bladder and that her intestines were full but they couldn’t see her appendix, which her physician thought might be the source of the bulge. The parents were told to purchase enemas and start giving them in addition to the high dose of laxative and, if nothing happened, to return in a week. Nothing was helping. While giving the youngster a tummy rub, her mother noticed a lump that was just above her left hip bone and also noted that her left leg was swelling. Three weeks after the initial visit with the PA, she was taken back to the doctor and another ultrasound was ordered but this time at the annex of the children’s hospital. The scan showed a large mass so a CT scan was ordered. The doctor said it was the largest mass he had ever seen in a child of her size and that it was almost certainly cancer. Now four weeks since the initial visit, the diagnosis was given to the parents - stage 4, group 4 Rhabdomyosarcoma.
  
  

Indicators of Rhabdo

While certain risk factors have been identified, in general, the causes of RMS are not yet fully understood.

Adapted from the National Cancer Institute:

• A possible sign of childhood rhabdomyosarcoma is a lump or swelling that keeps getting bigger.

• Lumps and other symptoms may be caused by childhood rhabdomyosarcoma. The symptoms that occur depend on where the cancer forms. Other conditions may cause the same symptoms. Check with a doctor if your child has any of the following problems:

• A lump or swelling that keeps getting bigger or does not go away. It may be painful, but sometimes it is not.

• Bulging of the eye.

• Headache.

• Trouble urinating or having bowel movements.

• Blood in the urine.

• Bleeding in the nose, throat, vagina, or rectum.

• Rhabdo can be an extremely fast growing cancer that can metastasize (spread) to other parts of the body. It is important that it be diagnosed quickly.

For additional information and an extensive list of resources, please check out the Resource Pages.