Discussion

Cardiac myxoma is a rare neoplasm in paediatric patients, with incidence increasing with age. Once diagnosed, prompt surgical resection is recommended, even in asymptomatic cases. Prognosis is generally favourable, with a low recurrence rate. ^{Reference Shi, Wu and Fang2} However, certain neurological complications can be severe and significantly increase mortality in cardiac myxoma patients. ^{Reference Holley, Martin and Brenner1}

Visual dysfunction due to cardiac myxoma is rarely reported in paediatric patients, and vision loss as an initial symptom in children is even more uncommon. ^{Reference Rosário, Fonseca, Sotero and Ferro3} Transient and permanent vision loss typically result from retinal artery involvement and localised thrombosis. In younger patients, retinal arteries may be obstructed by emboli or vegetations from cardiac arrhythmias, valve disease, endocarditis, or myxoma. A few cases of retinal embolism due to cardiac myxoma have been documented in paediatric patients, and such embolism may lead to irreversible damage due to the limited window for intervention. Therefore, it is essential to exclude cardioembolic causes in children and young patients presenting with stroke-like symptoms without apparent risk factors, particularly those with sudden vision changes.

Brain metastases, a rare neurological complication of cardiac myxoma, can be devastating. These metastases disrupt normal neurological function, leading to significant morbidity and mortality. Although myxoma is typically considered a benign tumour, its location may impart malignant potential, particularly in cases of multilobulated and villous myxomas. In such cases, tumour emboli can disseminate through the circulatory system, causing infarction. Furthermore, these emboli may penetrate the walls of small blood vessels, invading normal tissues and resulting in a space-occupying effect. ^{Reference Shi, Wu and Fang2,Reference Rosário, Fonseca, Sotero and Ferro3}

The diagnosis of the brain lesion in this patient was established using a combination of diagnostic imaging techniques. Echocardiography revealed no evidence of tumour recurrence, while positron emission tomography imaging showed hypometabolic lesions, consistent with myxoma characteristics. Histopathological examination further confirmed the presence of similar histological and molecular features. Ultimately, it was determined that the brain lesion originated from the cardiac tumour. Moreover, the child’s MRI revealed multiple new lesions compared to scans taken one-year prior (Figure 2), suggesting the occurrence of multiple intracerebral tumour emboli before myxoma resection. Some of these emboli may have contributed to the patient’s blindness and mild muscle weakness, while others may have progressively caused a space-occupying effect. Predicting potential metastases based solely on histology is challenging. Surgical resection does not eliminate the risk of delayed neurological complications, as these may arise long after myxoma removal. However, in patients exhibiting embolic symptoms, the tumour’s instability increases susceptibility to future brain haemorrhage and metastatic disease. ^{Reference Brinjikji, Morris and Brown4}

Cases of myxoma-associated brain metastases are rare and no standard therapeutic approach exists. In this case, following craniotomy, subsequent monitoring and follow-up are being undertaken. If tumour progression occurs, additional surgical resection or radiofrequency ablation may be pursued. A review of the extant literature indicates that surgical resection is the primary treatment for progressive nerve damage when the number of lesions is limited. In cases with multiple metastases, radiotherapy and chemotherapy may be considered. ^{Reference Bernet, Stulz and Carrel5,Reference Khong, Abou-Hamden, Koszyca, Roos and Govindaraj6} Panos et al. found fractionated low-dose whole-brain radiotherapy effective for treating myxoma-associated brain tumours and aneurysms in adults. ^{Reference Panos, Brunel and Berezowska7} The combination of Gamma knife radiosurgery and temozolomide has been effective for treating multiple myxoma brain metastases in adults. ^{Reference Ma, Zhao and Li8} Repeated resection has proven effective in patients with poor responses to radiotherapy or multiple recurrences. ^{Reference Abdow, Breton and Nayar9} However, few cases have been reported in paediatric patients. Moreover, radiation therapy in children requires great caution due to the risk of radiotherapy-induced neurotoxicity. The efficacy of chemotherapy for myxoma-related tumours remains inconclusive. ^{Reference Khong, Abou-Hamden, Koszyca, Roos and Govindaraj6}

This patient has been followed for approximately two years. We assert that surgical resection of the initial cardiac tumour is not the endpoint of treatment, and long-term follow-up is essential to monitor for tumour recurrence and the development of complications. In patients with neurological involvement, regular and comprehensive postoperative imaging is crucial due to the potential for rapid disease progression. A close follow-up is typically required for 3 to 5 years. Therefore, in patients with cardiac myxoma, particularly those who are young and have neurological involvement, prompt and complete tumour resection, along with long-term follow-up, are critical.