Embryonal tumour with multilayered rosettes

Embryonal tumour with multilayered rosettes (ETMR) is a rare and aggressive type of brain tumor that primarily affects infants and young children. It is characterized by its rapid growth and poor prognosis. ETMR falls under the broader category of embryonal tumors, which are a group of neoplasms that occur in the central nervous system (CNS) and share certain histological features reminiscent of embryonic development.

Classification

ETMR was previously classified under various names, including embryonal tumor with abundant neuropil and true rosettes (ETANTR), ependymoblastoma, and medulloepithelioma, reflecting its complex histological characteristics. However, with advancements in molecular genetics, these entities have been unified under the ETMR designation, emphasizing the importance of specific genetic alterations, notably the amplification of the C19MC (chromosome 19 microRNA cluster) locus, in their diagnosis.

Symptoms

The symptoms of ETMR are similar to those of other brain tumors and depend on the tumor's location within the brain. Common symptoms include increased intracranial pressure, resulting in headache, vomiting, and lethargy; seizures; and focal neurological deficits such as weakness or sensory loss. Due to the tumor's aggressive nature, symptoms often progress rapidly.

Diagnosis

Diagnosis of ETMR involves a combination of clinical assessment, imaging, and histopathological examination. Magnetic resonance imaging (MRI) is the preferred imaging modality, revealing a heterogeneous mass with varying degrees of enhancement after contrast administration. Definitive diagnosis, however, requires a biopsy or surgical resection of the tumor, followed by microscopic examination and molecular genetic testing to identify the characteristic C19MC amplification.

Treatment

The treatment of ETMR is challenging due to its aggressive behavior and tendency to recur. Standard treatment protocols typically include surgical resection to remove as much of the tumor as possible, followed by aggressive chemotherapy and radiation therapy. Given the poor prognosis associated with ETMR, treatment may also involve experimental therapies and enrollment in clinical trials.

Prognosis

The prognosis for patients with ETMR is generally poor, with a high rate of tumor recurrence and a low overall survival rate. The aggressive nature of the tumor and its resistance to conventional therapies contribute to the difficulty in managing this disease. Early diagnosis and comprehensive treatment are critical for improving outcomes, though research into more effective treatments is ongoing.

Research Directions

Research on ETMR is focused on understanding the molecular and genetic basis of the tumor to develop targeted therapies. The identification of the C19MC amplification as a key feature has opened new avenues for research, including the development of therapies that specifically target the molecular abnormalities in ETMR. Additionally, studies are exploring the role of stem cells in the tumor's development and the potential for immunotherapy in treating this aggressive cancer.