Published online Feb 27, 2017. doi: 10.4240/wjgs.v9.i2.68
Peer-review started: October 8, 2016
First decision: November 14, 2016
Revised: December 4, 2016
Accepted: December 28, 2016
Article in press: December 28, 2016
Published online: February 27, 2017
Processing time: 144 Days and 17.4 Hours
Extraskeletal osteosarcoma (ESOS) is an uncommon tumor that accounts for 1% of all soft tissue sarcomas and 4% of all osteosarcomas. Its presentation may be atypical, while pain has been described as the most common symptom. Radiological findings include a large mass in the soft-tissues with massive calcifications, but no attachment to the adjacent bone or periosteum. We present the case of a 73-year-old gentle man who presented with a palpable, tender abdominal mass and symptoms of bowel obstruction. Computer tomography images revealed a large space-occupying heterogeneous, hyper dense soft tissue mass involving the small intestine. Explorative laparotomy revealed a large mass in the upper mesenteric root of the small intestine, measuring 22 cm × 12 cm × 10 cm in close proximity with the cecum, which was the cause of the bowel obstruction. Pathology confirmed the diagnosis of an ESOS. ESOS is an uncommon malignant soft tissue tumor with poor prognosis and a 5-year survival rate of less than 37%. Regional recurrence and distant metastasis to lungs, regional lymph nodes and liver can occur within the first three years of diagnosis in a high rate (45% and 65% respectively). Wide surgical resection of the mass followed by adjuvant chemotherapy or radiotherapy has been the treatment of choice.
Core tip: We present the case of an elderly man who presented with a palpable abdominal mass and signs of intestinal obstruction. Intra-operative findings revealed a mass in the right abdomen involving the small intestine, which was widely resected. A diagnosis of soft tissue osteosarcoma was confirmed by pathology; further treatment with chemotherapy followed. To our knowledge it has never been reported a case of abdominal obstruction due to soft tissue sarcoma in the literature. Due to its rarity, we strongly believe that the presentation of this case would contribute to further understanding of the biology and management of this tumor.