23rd Aug 2021

ICRI CASE OF THE WEEK

Contributed By:
Dr Sriviruthi B, Dr Uma Maheshwari K B, Dr Nanjaraj C P, Dr Sanjay P,

Dr Pradeep H N, Dr Murali
Department of Radio-diagnosis
Mysore Medical College and Research Institute, Mysore

Copyright of the Case belongs to : Dr Sriviruthi B

Clinical Details

• A 20 year old female, primigravida who was on admission for missed
abortion, was incidentally found to have left chest wall swelling.

• The patient alleged h/o having noticed the swelling since 3 months.
• No h/o pain over the swelling.
• No h/o trauma.
• Not a K/C/O DM, HTN, TB or familial cancers.
• No h/o previous surgery.

Chest Radiograph

Ultrasound Chest

Plain CT Thorax

Contrast enhanced CT

3D VRT

Findings Rib
destruction
• White-out left hemithorax with
homogeneous radio-opacity in the left Better appreciated in the CT topogram
lateral chest wall causing tracheo-
mediastinal shift to right side.

• Destruction of lateral aspect of left 6th
rib also noted.

Findings

• Heterogeneous lesion with anechoic areas within - cystic/ necrotic
areas.

• On Colour Doppler, e/o significant internal vascularity noted.

Findings

• Large, heterogeneously enhancing soft tissue density lesion with non-
enhancing areas within (s/o necrosis), arising from the left lateral
chest wall involving left hemithorax with extra thoracic extension and
bony destruction.

• Moderate fluid in left pleural cavity, with thickening and
enhancement of left parietal pleura- s/o malignant pleural effusion.

Diagnosis

Askin tumour/ Peripheral Primitive
Neuroectodermal Tumour (PNET)-
Ewing’s sarcoma of chest wall

Histopathology - Sheets of small round blue cells

Discussion
Ewing sarcoma family of tumours (ESFT)

• Postulated origin from embryonal neural share a karyotype abnormality with
crest cells translocation involving

• Based on the point of origin of tumour, chromosomes 11 and 22.
this group includes
Histologically, these lesions
1) Osseous Ewing’s sarcoma demonstrate crowded sheets of

2) Extra skeletal Ewing sarcoma small round blue cells.

3) Peripheral Primitive Neuroectodermal
Tumour (pPNET)

4) Askin tumor (pPNET arising from chest
wall) - Small cell cancer of
thoracopulmonary region

Chest wall Ewing’s

• Primitive neuro-ectodermal tumors (PNETs), originally known as Askin tumors,
are malignant small round cell tumors that typically affect children and
adolescents.

• They are typically unilateral, aggressive masses that originate in the chest
wall, destroy bone, and are typically associated with pleural effusion.

• Females are affected more commonly than males (3:1).

• Detection of associated rib destruction establishes the tumor location
within the chest wall.

• In an adult, the most common etiologies of rib destruction are metastatic
lesions, multiple myeloma, and chondrosarcoma. In children and
adolescents, the most likely neoplasms include Ewing sarcoma,
neuroblastoma, lymphoma, and Askin (PNET) tumor.

Radiographic Findings

• Best diagnostic clue • Size
• Large unilateral extrapulmonary • Typically quite large; explosive

mass in a young adult growth
• Best imaging tool • Morphology
• CT: Skeletal involvement and • Soft tissue mass ± multicystic

metastatic disease components
• MRI: Optimal evaluation of soft • Rib destruction in 25-63% of cases
• Pleural effusion is frequent
tissue involvement • Lymphadenopathy; metastases to
• Location
• Chest wall, pleura lung &/or bone

Extrathoracic/extraosseous origin

• CECT

• Heterogeneous soft tissue mass

• Hemorrhage, necrosis, cystic change– Calcification is rare

• Invasion of chest wall, pleura, lung, mediastinum

• The mass tends to displace, rather than encase the adjacent organ.

• Linear and nodular density in the subpleural fat, which may represent
local perilymphatic and perineural extension, is an unfavourable
prognostic sign.

• MR Findings

• T1WI - Heterogeneous mass, mixed signal intensity

• T2WI – Heterogeneous, intermediate/high signal intensity

• T1WI C+ - Enhances with gadolinium

• Post-contrast T1-weighted imaging can demonstrate the boundary
and parenchyma of the tumor, as well as the blood supply of the
mass.

• Nevertheless, the radiologic characteristics of Askin tumors are not
specific, but imaging can be valuable for evaluating the extent of the
tumor, the response to treatment and local recurrences or distant
metastases.

PET/CT
May be used for staging of disease, assessing

response to therapy, and detecting tumor
recurrence

high signal intensity in the
tumor

aggressive periostitis intense FDG uptake within
the tumor

diffuse heterogeneous contrast
enhancement

References

• Se Jin Nam et al. Imaging of Primary chest wall tumours with
Radiologic-pathological correlation. RadioGraphics 2011; 31, 749-770.

• Rosado-de-Christenson, Carter. Specialty Imaging: Thoracic
neoplasms. Elsevier; 2016p442-443.

• Caffey’s Pediatric diagnostic imaging, 12th ed.Elsevier;637-644.