A Case Report on Extraskeletal Osteosarcoma

Sir,

With reference to the article published on extraskeletal osteosarcoma (ex-ogs) - DOI: 10.7860/JCDR/2016/16183.7065, YEAR: 2016/ Month: Jan/ Volume: 10/ Issue: 01.

We raise certain queries and would like to add some critical points based on present multidisciplinary guidelines for the management of these rare tumours.

Evaluation: The initial evaluation for distant metastasis with only chest X ray is inadequate. These high grade tumours frequently metastasize to lungs, bone and regional lymph nodes [1,2]. Thus require a detailed staging evaluation with computed tomography scan of lungs, bone scan and ultrasonography of regional lymph nodes (though recently Positron emission tomography scan is gaining popularity as a single modality for staging evaluation).

Treatment: Authors have stated that the patient was treated with only surgery, which again is an inadequate treatment for an deep seated ex-ogs of more than 5 cm. Prechemo era had dismal outcomes in these tumours. Recent studies have shown improved result with the use of doxorubicin and ifosfamide based regimens as used in soft tissue sarcomas. Currently, a multi modality approach is used to treat extra skeletal osteosarcoma, which entails incorporation of multi drug chemotherapy and /or radiotherapy along with the surgery to get the best outcome in terms of disease specific survival and local relapse free survival [3]. Thus, based on the latest evidence available; this case should have been treated with adjuvant chemotherapy and radiotherapy in addition to surgery.

Follow up: A standard follow up protocol is required as these tumours have shown high propensity to metastasize and recur locally. We recommend a 6 monthly follow up with clinical examination of local part and regional lymph node (if suspicious, ultrasonography is recommended) and a chest X ray for five years and then at yearly interval till 10 years [4].

The article was written from a pathologist’s view point. However, the reader emphasized on evaluation, treatment and follow up. We agree that lung is the most frequent site involved in the metastasis from the Extraskeletal Osteosarcoma (ESOS), only a chest radiograph was taken in our case and as rightly pointed out by the reader; evaluation of other sites should also be done.

There is disagreement among various authors in the literatures regarding the treatment of ESOS. According to some authors, it is less chemosensitive and radiosensitive compared to the conventional osteosarcoma and treating the patients with chemo/radiotherapy in adjunct to surgery, depends upon individual risk factors [1]. According to some, adjuvant chemotherapy and radiation therapy are offered to patients with incomplete resections and to those with large (>5cm) or high grade tumours [2]. Literature also documents that chemo/radiotherapy is reserved for ESOS with metastasis [3]. Follow up protocol as mentioned by the reader is necessary and in our case too we recommended a long term follow up.

Thanks,

shifafrin@gmail.com

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