Brain and spinal tumours: Case

Framing the case

This seven-year-old girl has the classic presentation of a posterior fossa tumour with obstructive hydrocephalus. The progressive early morning headache that wakes her from sleep, the vomiting that relieves it, the papilloedema, the false-localising right sixth palsy, and the truncal ataxia with the dysmetria, together make a posterior fossa mass the working diagnosis, and the first decision is to move the child from an elective workup to an emergency resuscitation. The framework that organises the case is the location, the posterior fossa, and the biology, the embryonal medulloblastoma that is the commonest malignant brain tumour of childhood. [2][3]

Immediate assessment and stabilisation

The assessment begins with the airway, the breathing and the circulation, and the level of consciousness, because a drowsy child with the papilloedema and the ataxia is at risk of the herniation from the unrelieved hydrocephalus. The child is admitted to a paediatric neuro-oncology centre, and the dexamethasone is started at zero point one to zero point two milligrams per kilogram per dose every six hours to control the vasogenic oedema. The head is elevated, the isotonic fluids are maintained, and the neurosurgical and the oncology teams are alerted. The hydrocephalus is managed with the external ventricular drain at the surgery or before it, because the obstructed cerebrospinal fluid pathway is the immediate threat. [11]

The diagnostic pathway

The magnetic resonance imaging of the brain with and without contrast confirms the posterior fossa mass, the oedema, the hydrocephalus and the relationship to the fourth ventricle and the brainstem. The whole neuraxis is imaged at the diagnosis because the medulloblastoma disseminates through the cerebrospinal fluid, and the spinal magnetic resonance shows no drop metastases. The cerebrospinal fluid cytology, sent once the pressure is relieved, shows no malignant cells. The maximal safe resection is performed, and the residual tumour on the postoperative scan measures under one point five square centimetres. The histology confirms the medulloblastoma, and the molecular studies place it in the molecularly average-risk category. [3][4]

The named diagnosis and the definitive management

The diagnosis is a non-metastatic, molecularly average-risk medulloblastoma. The definitive management is the maximal safe resection, already achieved, followed by the craniospinal irradiation at twenty three point four gray to the neuraxis with a boost to the posterior fossa, combined with the concomitant and the maintenance chemotherapy. The molecular subgroup refines the risk, with the WNT carrying the best and the Group 3 the worst prognosis, and the contemporary survival of the average-risk medulloblastoma sits around seventy to eighty percent. The proton therapy is increasingly used to reduce the late effects. The treatment runs over roughly a year. [3][4]

The girl is enrolled on the national protocol, and the multidisciplinary team is assembled: the paediatric oncologist, the neurosurgeon, the radiation oncologist, the endocrinologist, the neuropsychologist, the clinical nurse specialist, the social worker and the educational liaison. The family is taught the recurrence signs, the late effects, the central line care and the school support. The survivorship plan is begun from the day of diagnosis. [12]

Contrasting the brainstem lesion

The examiner asks the candidate to contrast this resectable medulloblastoma with the diffuse intrinsic pontine glioma. A child with the diffuse intrinsic pontine glioma would have the short history of the cranial nerve palsy, the pyramidal signs and the ataxia, and the magnetic resonance would show the diffusely enlarged pons that encases the basilar artery. The diagnosis would be radiographic, defined by the H3 K27M mutation, and the treatment would be the focal radiotherapy to the pons at fifty four to fifty nine gray with no curative intent, because the prognosis is near uniformly fatal within the year. Holding these two brainstem-region tumours together, the resectable medulloblastoma and the fatal diffuse intrinsic pontine glioma, is the reasoning the boards reward. [7]

Communication and the family

The family is counselled honestly and hopefully. The candidate names the diagnosis, explains that it is the commonest malignant brain tumour of childhood, that the contemporary survival sits around seventy to eighty percent for the average-risk disease, and that the treatment runs over roughly a year. The parents are introduced to the multidisciplinary team, given a written plan, taught the recurrence and the late-effects surveillance, and supported by the social work and the educational liaison. The girl is prepared in an age-appropriate way, and the siblings and the school are included. The fellow who can hold the science and the humanity together in this conversation demonstrates the reasoning the boards reward. [12]