CASE 13108 Published on 25.04.2016

Primary posterior mediastinal yolk sac tumour in a two-year-old girl

Section

Paediatric radiology

Case Type

Clinical Cases

Authors

W Douira Khomsi, MD1, S Moalla, MD1, F Fedhila, MD2, I Ammar, MD1, I Bellagha1

(1) Department of Pediatric Radiology
(2) Department of Pediatric A
Bechir Hamza Children Hospital
1007 Jebbari, University el Manar
Tunis, Tunisia;
Email:salma.moalla29@gmail.com
Patient

2 years, female

Categories
Area of Interest Thorax, Oncology, Paediatric ; Imaging Technique Digital radiography, Ultrasound, CT
Clinical History
A 2-year-old girl was referred to our department for respiratory distress. There was no relevant information in her past medical history. Physical examination revealed respiratory distress with intercostal and sub-sternal retractions, and tachycardia. The right hemithorax examination showed decreased movements, absolute dullness and suppressed breath sound. The AFP level was remarkably high.
Imaging Findings
Chest X-rays showed a right opaque hemithorax with a mediastinal shift due to a large right pleural effusion (Fig. 1). A chest and lung ultrasonography (US) was performed and showed a hyperechoic mass with dented edge located in the mid inferior part of the right hemithorax associated with a pleural effusion [2].
The patient was transferred to cardiovascular surgery department because of the worsening of her respiratory state. An exploratory thoracotomy was urgently performed and revealed a fragile mediastinal mass invading the parietal pleura. Resection of the tumour was not attempted. Instead, biopsies were taken and a drain tube was left.
CT-scan (computed tomography) revealed a large posterior mediastinal mass spreading in the inframediastinum posterior space, repressing cardiac cavities and invading the adjacent pleura and the diaphragm (Fig. 3 a, b, c, d and Fig. 4). A capsular rupture was noticed. Mediastinal and coeliac lymphadenopathies were detected in addition to pleural and hepatic metastasis.
Discussion
Yolk sac tumour (YST) is a primitive malignant germ cell tumour (GCTs) that is uncommon in clinical practice and seems to have a special predilection for males [1]. It occurs mostly between one to five years of age involving most frequently gonads than extragonadal sites [2] with a predilection of anterior mediastinum [3]. Our report contradicts common literature data as far as our patient is female and the tumour is localized at the posterior mediastinum. To our knowledge, this is the second female patient case with a primary posterior mediastinal YST.
There are no specific clinical signs for YST.
The finding of an elevated AFP serum level is useful in the diagnosis and follow-up of these patients [3] and should be measured at presentation and monitored during treatment. They are very useful in diagnosis and in evaluating the effectiveness of therapy [4]. The dosage of this parameter can be sufficient to the diagnosis without histological confirmation [4]. The rate should be superior to 1000 kUI/L.
Radiology can aid in surgical planning, and avoid inappropriate management, and may enable the surgeon to plan the adequate procedures [1].
According to Li and Al [1], the CT (Computed Tomography) aspect of YST ranges from entirely solid to predominantly cystic or presents as heterogeneous appearances consisting of a mixed solid and cystic nature and tend to grow in an expansive centripetal fashion with compression of adjacent organs. On unenhanced CT, the solid portion of YST appeared as isodense to normal muscle. Enhancement can be more or less marked. Its heterogeneity may be due to intralesional haemorrhage, necrosis, or cystic change. CT can also pinpoint capsular rupture which may lead to a large spread into the adjacent structures, such as abdominopelvic cavity, surrounding soft tissue space, pleural cavity, lung parenchyma, or tracheobronchial tree. This may cause inflammation, adhesion, metastasis implantation, or invasion and compression of adjacent organs. Intratumoral calcification and fatty tissue, although rare, may indicate a mixed YST containing a teratoma component.
YST are chemosensitive. Surgical excision is also an important step for the treatment of these tumours [4]. Radiotherapy has no place in YST management [4]. Surgery increased the response rate to 42 % [4]. Analysis of the operative specimen suggests that surgical removal is necessary after chemotherapy as far as follow up cannot be based solely on AFP rate. Prognosis is intimately linked to the rapid onset of the treatment and to the initial extension of the tumour.
Differential Diagnosis List
Yolk sac tumour arising within the posterior mediastinum
Rhabdomyosarcoma
Teratoma
Final Diagnosis
Yolk sac tumour arising within the posterior mediastinum
Case information
URL: https://www.eurorad.org/case/13108
DOI: 10.1594/EURORAD/CASE.13108
ISSN: 1563-4086
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