Multiple Intra-abdominal Leiomyosarcoma in a Single Patient

Leiomyosarcomas (LMS) are malignant lesions that develop from the smooth muscles of blood vessels, visceral organs and uterus. It is the predominant sarcoma originating from the large blood vessels. Leiomyosarcoma originating from small bowel or intra-abdominal blood vessels is very rare. We report a unique and rare case of multiple synchronous leiomyosarcomas originating from blood vessels of mesentery, omentum and bowel.

Case Report

Forty-one-year-old male patient was presented to the emergency department with gross distension of abdomen, bilious vomiting, melena and anaemia. On examination, he had a huge mass in the abdomen with a poor general condition. Computerised tomography (CT) showed a large mass in the upper abdomen with multiple small tumours. Image-guided biopsy of the large mass showed spindle cell tumour. There was no distant metastasis. In view of acute intestinal obstruction, he underwent surgery with probable preoperative diagnosis of gastrointestinal stromal tumour (GIST). The large mass was 30 cm in size in the upper mesentery involving the proximal jejunum. It was removed intact along with jejunum. Multiple small independent tumours ranging in size from 1–5 cm, present over the omentum, small and large bowel, mesentery, peritoneum and urinary bladder, were removed (Fig. 1). At initial look, we were not sure of removing all tumours but we held our nerves and persisted with patience as surgery was the only curative option. All tumours were well-encapsulated, distinct and not muscle invasive. There was no sign of capsule rupture to suspect peritoneal sarcomatosis. All visible tumours were meticulously removed from the abdomen (cytoreductive surgery including omentectomy, peritonectomy). The total number of tumours removed was more than 340. Final biopsy reported it as intermediate grade leiomyosarcoma on histological features and immunohistochemistry (positive for SMA, caldesmon and vimentin; negative for CD 117, DOG-1, CD34), with high Ki67 (50%) and mitosis of 22–25/50HPF. Mutation analysis for c-KIT and PDGFR was negative. Postoperative recovery was speedy and uneventful. After discussing in the tumour board meeting, he received 6 cycles of Adriamycin and ifosfamide adjuvant chemotherapy. He is doing well on 6 months of follow-up.

Fig. 1.

Intraoperative and imaging picture

Discussion

Leiomyosarcomas account for 11% of all soft tissue sarcomas (STS) [1]. We had never seen so many independent synchronous tumours in a single patient and neither is it reported in the literature, and we were able to successfully remove all the tumours. The possible origin is from the muscle layer of smaller blood vessels as the tumour was not infiltrating in to muscle layer of bowel or bladder. It is important to differentiate LMS from GIST in the abdomen. Though histologically our case did not have features of GIST, it was ruled out following the algorithm of Asian consensus guidelines [2]. Multiple soft tissue sarcomas on extremity and retroperitoneum in a single patient were reported but only few were synchronous [3]. Synchronous is defined as second tumour developing within 6 months of the previous diagnosis. It is difficult to ascertain whether they truly represent multiple distinct primaries or metastasis. Usual spread of LMS is by hematogenous route, liver and lung being the most common sites [4]. Our case cannot be categorised as benign metastasising leiomyomas as there was significant cellular atypia with high mitotic index and Ki67.

Surgery is the only curative option and every effort should be made to achieve R0 resection. There is no standardized chemotherapy but anthracycline based or gemcitabine and docetaxel combination are most commonly used. Few studies have reported promising outcomes with complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC), especially with melphalan in recurrent intra-abdominal sarcoma with peritoneal sarcomatosis [5]. Incomplete resection with HIPEC did not achieve good outcome. More recently, in advanced cases who have received prior chemotherapy, pazopanib is used as an effective salvage therapy [6]. To conclude, it is a rare case of multiple synchronous leiomyosarcomas originating from smaller blood vessels, and complete cytoreduction with newer adjuvant treatment modalities will give more hopes for improving the survival.