SESSION TITLE: Cancer Cases
SESSION TYPE: Case Reports
PRESENTED ON: Sunday, March 23, 2014 at 09:00 AM - 10:00 AM
INTRODUCTION: Cancer has been described as a civil war raging within the body. Advances in cancer treatment has improved survival, but also highlighted the long term adverse effects of treatment.
CASE PRESENTATION: A 37-year-old female, non smoker, was referred to the respiratory department after a chest radiograph to investigate symptoms of respiratory tract infection, detected a pulmonary mass lesion. She had a past history of Hodgkin’s Lymphoma stage IIB at the age of 24.Treatment with curative intent was initiated with Adriamycin, Bleomycin, Vinblastine and Dacarbazine. Unfortunately she had only partial response to chemotherapy and it was decided to proceed with radical radiotherapy as the primary treatment modality. She had mantle field radiotherapy to her neck and thorax (36 Gray) and 36 Gray to the paraaortic/splenic region, with good response. Subsequent follow-up confirmed cure. Her current presentation was investigated with a chest CT scan followed by CT guided biopsy of the lesion, which revealed features suggestive of adenocarcinoma. PET scan showed a PET avid lesion in the left upper lobe with no evidence of metastatic disease. Since her diffusion capacity (DLCO) was only 51%, she was treated with wedge resection (rather than lobectomy) of the left upper lobe mass. The histology revealed malignant spindle-cell and epithelioid tumor with positive staining for pan-cytokeratins and lack of labelling for CEA, CD15, CD117 and TTF-1, confirming the diagnosis of synovial sarcoma. Molecular studies using total RNA extracted from tumor tissue was performed using TriReagent. Reverse transcription followed by PCR of the junctional regions of the SYT-SSX1 and SYT-SSX2 fusion gene transcripts resulted in a positive band at the expected size, corresponding to positivity for the SYT-SSX transcript and confirming the diagnostic translocation.The patient had an uneventful post-operative period and follow-up after 1 year revealed no evidence of recurrence.
DISCUSSION: Newer treatment modalities have made a significant impact on the survival of patients with cancer which has highlighted the long term adverse effects associated with treatment.Radiation associated sarcomas are defined as sarcomas arising in a previously irradiated field after a minimum latency of 2 years. Their incidence is estimated to be between 0.03%-5% .Osteosarcoma is the commonest histological subtype of post-radiation sarcoma. There is a linear association between the total dose of radiation and risk of radiation-associated bone sarcomas. These tumors tend to arise at the margin of the radiation field (as in this reported case), probably due to mutagenic effect of the radiation (dose of radiation sufficient to cause mutation but insufficient to cause death of the cells).Murray et al proposed the following criteria for diagnosis of radiation associated sarcoma  - 1. History of prior irradiation and tumor development at this site 2. No evidence of sarcoma prior to irradiation 3. Histologically different from the primary tumor The synovial sarcoma reported in this case fulfils the above criteria. The latency period of the tumor conforms to the mean latency of 10-20 years, reported in the literature. Synovial sarcomas are seen more often in adolescents and young adults. Their development is linked to the chromosomal translocation t(X;18) involving either SSX1 or SSX2 genes on chromosome Xp11 and the SYT gene from chromosome 18 q11.Post-radiation synovial sarcomas are reported to have similar clinical, morphological, immunohistological and molecular characteristics when compared to sporadic synovial sarcomas. There has been a previously reported case of pulmonary synovial sarcoma secondary to radiotherapy to pulmonary metastases from Wilm’s tumor . This is the first reported case of radiotherapy associated synovial sarcoma in an otherwise healthy lung.
CONCLUSIONS: Radiation associated sarcomas should be considered in the differential work-up of solitary pulmonary nodule/mass in a patient with previous radiotherapy to the thorax.
Reference #1: Laskin, W.B., T.A. Silverman, and F.M. Enzinger, Postradiation soft tissue sarcomas. An analysis of 53 cases. Cancer, 1988. 62(11): p. 2330-40.
Reference #2: Wolden, S.L. and K.M. Alektiar, Sarcomas across the age spectrum. Semin Radiat Oncol, 2010. 20(1): p. 45-51
Reference #3: Murray, E.M., et al., Postradiation sarcomas: 20 cases and a literature review. Int J Radiat Oncol Biol Phys, 1999. 45(4): p. 951-61
DISCLOSURE: The following authors have nothing to disclose: Vinod Aiyappan, Sonja Klebe, Doug Henderson, Anand Rose
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