Introduction
Embryonal rhabdomyosarcoma (EMRS) is an uncommon form of connective tissue cancer. It primarily affects youngsters and is typified by cancerous cells that resemble the earliest skeletal muscle cells in developing embryos. The reason it is known as PAX-fusion negative rhabdomyosarcoma is that it does not have a particular fusion gene, which is a gene combination of two different genes. Alveolar rhabdomyosarcoma is a different kind of rhabdomyosarcoma that is frequently associated with this fusion gene. What sets embryonal rhabdomyosarcoma apart is the lack of this fusion gene. Because these tumors closely mimic the growing skeletal muscle in embryos and fetuses, they are called "embryonal" tumors.
How Is Embryonal Rhabdomyosarcoma Classified?
The most prevalent kind of rhabdomyosarcoma, a cancer of childhood, is embryonal rhabdomyosarcoma (ERMS). It accounts for 60 to 70 percent of cases; alveolar rhabdomyosarcoma (ARMS) is the name of the other type. ERMS can happen at any age, however, it is most commonly observed in children aged from zero to five. There are three subtypes of it: spindle cell, not-otherwise-specified (NOS), and botryoid. There are distinct genetic mutation mechanisms in ERMS and ARMS. The World Health Organization now considers both molecular genetics and appearance when classifying rhabdomyosarcomas instead of relying only on morphology. In a 2013 study, increased mutation rates were observed in embryonal rhabdomyosarcoma (ERMS), specifically within the RAS pathway, when compared to alveolar rhabdomyosarcoma (ARMS). Males are at greater risk than females of being diagnosed with ERMS.
What Are the Histological Features of Embryonal Rhabdomyosarcoma?
Embryonal rhabdomyosarcoma is frequently referred to as a "small round blue cell tumor" because of the way hematoxylin and eosin stains cause its cells to appear under a microscope. Upon detailed examination, the tumor usually exhibits a combination of dense and loose cell patches, containing both spindle- and round-shaped cells. This complex structure is similar to the several phases of muscle growth in the embryo.
What Is the Common Location of Embryonal Rhabdomyosarcoma?
Embryonal rhabdomyosarcoma is a soft tissue tumor that can develop anywhere in the body, however, it most frequently affects the "head and neck or the genital or urinary organs." Organs such as the bile duct, bladder, and vagina that have mucous linings are susceptible to the botryoid kind. Because it resembles bunches of grapes, the word "botryoid" was coined.
What Are the Symptoms of Embryonal Rhabdomyosarcoma?
The position of the tumor affects the symptoms. For example, a child with an ear tumor may have discharge or ear pain. Swelling or protrusion from the socket may result from a malignancy behind the eye. Depending on where the tumor is, other symptoms might be:
-
Muscle of Arm or Leg: The presence of a painful lump, swelling, or mass.
-
Stomach: Experiencing nausea, vomiting, or abdominal discomfort.
-
Urinary Tract and Bladder: Hematuria, or the presence of blood in the urine, or difficulty urinating.
-
Nasal Cavity: Recurrence of sinus infection-like symptoms or nosebleeds (epistaxis).
-
Vagina: The existence of a developing lump or mass in the vagina.
-
Testicles: Rapidly expanding mass or lump surrounding the testicles.
What Are the Causes of Embryonal Rhabdomyosarcoma?
Embryonal rhabdomyosarcoma (ERMS) is caused by abnormalities in the body's RAS system and specific genes. Some chromosomes (two, eight, 11, 12, 13, and 20) acquire material in ERMS, while others (10 and 15) lose material. Additionally, chromosome 11p has a common mutation. p53 loss, stimulation of the RAS pathway, and mutations in MYOD1 are examples of specific gene alterations associated with ERMS. The gene modifications in fusion-negative ERMS and fusion-positive ERMS are different. RAS mutations are frequent and provide a strong signal that promotes tumor development. In addition, ERMS can result from mutations in tumor suppressor genes such as MYOD1 (approximately three percent of cases) and TP53 (13 percent of cases). Anaplasia, a disorder with malformed cells linked to poorer outcomes, may result from TP53 mutations.
What Are the Predisposing Factors for Embryonal Rhabdomyosarcoma?
Neurofibromatosis and Gorlin syndrome are two inherited disorders that raise the risk of developing embryonal rhabdomyosarcoma. Additional risk factors include drug use by mothers, smoking, exposure to X-rays, and older parental ages. The risk factors for neurofibromatosis type one, Noonan syndrome, and Costello syndrome are increased by mutations in the RAS cell signaling system. When it comes to appearance, inherited genetic abnormalities that cause ERMS are indistinguishable from spontaneous mutations.
How Is Embryonal Rhabdomyosarcoma Diagnosed?
Rhabdomyosarcoma is diagnosed by evaluating the appearance under a microscope and performing tests with markers connected to the formation of muscle. Protein expression is used in immunohistochemical testing to determine if rhabdomyosarcoma is fusion-positive or fusion-negative. These days, molecular classification is being used more often than appearance alone since appearance cannot identify the sort of fusion. Genetic testing is used to determine the subtype and confirm the diagnosis. The results are compared with the patient's clinical presentation.
What Are the Treatment Options for Embryonal Rhabdomyosarcoma?
Surgery to remove the tumor is the primary line of therapy for the majority of patients with rhabdomyosarcoma. Chemotherapy and radiation are combined if surgery is not an option. Drugs used in chemotherapy include vincristine, cyclophosphamide, and actinomycin D, which work to destroy cancer cells and stop them from growing in the future. Chemotherapy's side effects, however, might include suppression of the immune system and nausea. Another alternative is radiation therapy, which uses high doses of radiation and frequently results in skin irritation and fatigue as side effects.
Radiation therapy and surgery are frequently effective forms of cancer treatment for patients with localized tumors. Treatment becomes more difficult if the cancer has spread (metastasized), particularly to difficult locations like the lungs or bone marrow. With survival rates under 40 percent, current therapies for metastatic rhabdomyosarcoma have not improved significantly over the past few decades. High-dose chemotherapy can cause greater adverse effects and has not demonstrated a discernible improvement in survival when compared to regular chemotherapy. In clinical studies, researchers are investigating targeted therapies and immunotherapies to enhance patient outcomes and minimize adverse effects in individuals with more resistant rhabdomyosarcoma.
Conclusion
Embryonal rhabdomyosarcoma can cause a variety of symptoms, from urinary problems to earaches, depending on where it is located. Since these symptoms may initially resemble less serious disorders, early discovery and medical treatment are crucial. Individuals impacted by this uncommon malignancy can greatly improve their quality of life and get improved outcomes with prompt care.
