Case 2 :

A 13 year old female presented with fever, right sided chest pain and dyspnoea of 2 months duration.
Xray chest revealed a right opaque hemithorax with mediastinal shift to the left. CT scan chest was asked for.
What is your differential diagnosis ?

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Answer :

CT scan shows a homogenous, patchily enhancing mass lesion in the right hemithorax with rib destruction noted anteriorly. Differential diagnosis includes Ewing's sarcoma, PNET (primitive neuroectodermal tumour - Askin's tumour), malignant lymphoma and (less likely) rhabdomyosarcoma of the chest wall.
This patient was subjected to open chest biopsy; the specimen showed clusters of small ovoid cells arranged in a rosette formation. Periodic acid-Schiff (PAS) was negative and neuron specific enolase (NSE) was weakly positive. Final diagnosis was given as Askin's tumour.
In 1979, Askin et al described a chest wall tumour occuring in children which they called "the malignant small cell tumour of the thoraco-pulmonary region in childhood", now also known as the Askin's tumour, which is a rare malignant small cell neuroepithelioma arising from the soft tissues of the chest wall or lungs, and has also been classified as a PNET. CT guided FNAC, electron microscopy, and immuno histochemical examination helps to differentiate Askin's tumour from other chest wall masses.

References :
Saifuddin A, RobertsonRJH, Smith SEW. The radiology of Askin's tumours.Clin Radiol 1991; 43: 19-23
Gonzalez-Crussi F, Wolfson SL, Misugi K, Nakajima T. Peripheral neuro-ectodermal tumour of chest wall in childhood. Cancer 1984; 54: 2519-2527.

Contribution : Dr Amarnath Sortur, Dr Kiron Master, Detroit, USA.