CASE 13692 Published on 19.06.2016

Desmoplastic round cell tumour of pleura with liver and spine metastases: Uncommon pathology with grave prognosis

Section

Chest imaging

Case Type

Clinical Cases

Authors

Dr. Somit Mittal, Dr Amber Obaid

Jawaharlal Nehru Medical College,
Amu, Aligarh Muslim University;
Civil Lines 202001
Aligarh, India;
Email:somit999@gmail.com
Patient

20 years, female

Categories
Area of Interest Lung, Abdomen, Thorax, Bones, Soft tissues / Skin ; Imaging Technique CT, CT-High Resolution
Clinical History
A 20-year-old female patient was admitted to our hospital with complaints of chest pain, dyspnoea and weight loss for 6 months. X-ray chest revealed opacification of the left hemithorax. On examination dullness was noted in the left side of the chest. CT was advised.
Imaging Findings
Topogram demonstrated opacification of the left hemithorax with a shift of the mediastinum towards the right side (Fig. 1).
CT image morphology showed a heterogeneously enhancing circumferential irregular nodular pleural thickening on the left side, involving the entire pleural surface (Fig. 2a, 2b & 3a, 3b) with ipsilateral pleural effusion and metastases in liver and bone (Fig, 4a & 5).
The left diaphragm showed inferior displacement by the mass lesion without obvious trans-diaphragmatic extension. The only manifestation of disease in the abdomen was noted in the form of liver metastases (Fig. 4 & 5), however, no contiguous extension of the lesion was seen.
CT-guided biopsy revealed angulated nests of small cells embedded in a vascular fibroblastic stroma and areas of central necrosis.
On immuno-histochemistry the cells showed evidence of epithelial, mesenchymal, and neural differentiation with positivity for vimentin and desmin.
Discussion
Background: Desmoplastic small round cell tumour (DSRCT) is an extremely rare malignant neoplasm which is highly aggressive. It was initially reported by Rosai and Gerald in 1989 [1]. The histogenesis or pathogenesis of DSRCT is uncertain, mostly involving the abdominal and/or pelvic peritoneum [2]. It has also been reported in epididymis, ovaries, kidneys, pleura, soft tissues and bones. DSRCT usually occurs in young adults and adolescents in the age group of 16-26 years with male predilection and a male to female ratio of 4:1 [3, 4]. The diagnosis is usually confirmed by histological and immunohistochemistry studies [5].
Desmoplastic small round cell tumour (DSRCT) belongs to the group of “small round blue cell tumours”, which are characterised by sheets of small cells and round nuclei. The primary tumour most commonly arises in the peritoneal cavity, although DSRCT arising from other organs of the body like brain, lung, pleura etc. has been described. [6, 7] It is a very aggressive neoplasm with mean survival of 23 months. [8]
CT frequently shows multiple nodular, lobulated, heterogeneous peritoneal soft-tissue mass lesions with a predilection for spread to distant organs (including local, lymphatics and haematogenous modes of spread) without obvious primary organ involvement.
On histology these tumours show sharply demarcated, cohesive nests of uniform tumour cells with scanty cytoplasm; surrounded by abundant fibrous stroma. Immunohistochemistry of this peculiar tumour shows co-expression of various markers including epithelial, mesenchymal and neural origin.
Genetically DSRCT shows reciprocal translocation specifically between chromosomes 22 and 11, thereby leading to fusion of the Wilms’ tumour gene (WT1) and Ewing’s sarcoma gene (EWS) gene [t(11;22)(p13;q12)]. This type of reciprocal translocation of the EWS gene has also been reported in Ewing’s sarcoma and primitive neuro-ectodermal tumours, but the locus is separate on chromosome 11.
CT is the most useful tool for diagnosis and staging of DSRCT and should be the initial imaging test of choice. However, MRI can provide some further characterisation of the lesions of DSRCT (such as the presence of intralesional haemorrhagic necrosis). Fluorodeoxyglucose (FDG)-PET/CT has been shown to identify occult lesions not demonstrated on CT or MRI.
Treatment is limited to surgical resection with radiotherapy and chemotherapy.
Despite chemotherapy, radiotherapy, and aggressive surgical resection, the overall survival is poor (30-55% at 3 years, less than 15 % at 5 years).
Early diagnosis is crucial for disease management.
Differential Diagnosis List
Desmoplastic small round cell tumour
Desmoplastic small round cell tumour
Ewing's sarcoma/PNET
Final Diagnosis
Desmoplastic small round cell tumour
Case information
URL: https://www.eurorad.org/case/13692
DOI: 10.1594/EURORAD/CASE.13692
ISSN: 1563-4086
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