Retroperitoneal leiomyosarcoma mimicking acute appendicitis: laparoscopic management.

BACKGROUND: Retroperitoneal leiomyosarcomas (RLMS) are a challenging clinical entity. The vast majority of patients are operated on when tumors are advanced. We report herein a case of RLMS, mimicking acute appendiceal disease and treated successfully via laparoscopy.
METHODS: A 37-year-old woman, para 1, was admitted to our department for right lower quadrant abdominal pain, fever, and leukocytosis. She had no changes in gastrointestinal and urologic function. A physical examination revealed the presence of abdominal guarding, rebound, and a tender mass in the right lower quadrant. The abdominal ultrasound showed an inhomogeneous ovoid mass (6 cm in diameter) located below the cecum, with no definite margins, and consistent with an appendiceal abscess. The patient was referred for laparoscopy. The procedure was performed with the aid of 3 ports: a 12-mm trocar in the umbilicus (open technique), a 10-mm trocar in the left iliac fossa, and a 5-mm one in the supra-pubic space. On inspection of the abdominal cavity, a retroperitoneal 6-cm mass was immediately found below the cecum and the appendix. Neither intraperitoneal seeding nor suspected lymph nodes were present. After dissection of the parietal peritoneum, the mass appeared to be encapsulated and well demarcated from all surrounding structures. It was eventually dissected and removed via a plastic bag. A standard appendectomy was also performed. The postoperative course was uneventful, and the patient was discharged on the 3rd day. The histology analysis of the resected specimen showed a totally excised G2 leiomyosarcoma. The appendix had no signs of inflammation. Postoperatively, the patient underwent a total-body CT-scan, which had no signs of residual or distant disease. No adjuvant therapy was necessary. At an 18-month follow-up, the patient was doing well and was disease free.
CONCLUSION: Surgery represents the main therapeutic option for resectable RLMS. Laparoscopy is a useful diagnostic tool that allows safe resection of incidentally discovered, small and well encapsulated RLMS.

INTRODUCTION

Retroperitoneal tumors consist of a heterogeneous group of uncommon neoplasms of unknown cause, accounting for 1% to 2% of all adult solid tumors.[1-3] Leiomyosarcomas represent about 2% to 9% of all soft tissue sarcomas.[1-3] Although surgical resection is often challenging, currently available chemotherapy is not as effective and radio-therapy is limited by its toxicity to adjacent structures.[4-6] Thus, complete surgical resection remains the most effective modality for primary and recurrent disease.[4-7] Herein, we report a case of retroperitoneal leio.myosarcoma (RLMS), mimicking acute appendicitis and successfully treated with laparoscopy.

METHODS

A 37-year-old woman, para 1, was admitted to our department with a 72-hour history of right lower quadrant pain, fever (38.5°C), and leukocytosis (12.5 × 103/mL). No change had occurred in gastrointestinal and urologic function. No relevant notes in her past medical history existed. She was not on any medications and had no known allergies. A physical examination revealed the presence of abdominal guarding, rebound, and a tender mass in the right lower quadrant. The gynecologic examination was negative. Chest x-rays and EKG were normal. The abdominal ultrasound showed an inhomogeneous ovoid mass (6 cm in diameter) located below the cecum, with no definite margins, and consistent with an appendiceal abscess. After providing informed consent, the patient was referred for laparoscopy. The procedure was performed with 3 ports: a 12-mm trocar in the umbilicus (open technique), a 10-mm trocar in the left iliac fossa, and a 5-mm one in the suprapubic space. A 30-degree laparoscope was used. On inspection of the abdominal cavity, a mass was observed bulging through the posterior parietal peritoneum in the right iliac fossa, below the cecum and the appendix. No evidence existed of intraperitoneal seeding or enlarged lymph nodes.

The parietal peritoneum over the mass was incised with the electrocautery, and the anterior surface of the mass was isolated with blunt dissection. The mass appeared encapsulated and well demarcated from the posterior abdominal wall and the surrounding structures. It was eventually dissected free and removed via a plastic bag. Its vascular pole seemed to stem from the right ovary suspensor ligament. Titanium clips were used to control blood vessels. A standard appendectomy was also performed. The postoperative course was uneventful, with flatus passing on the 1st day, a clear liquid diet started on the 1st day and a solid diet on the 2nd day. The patient was discharged on the 3rd postoperative day. The gross pathologic examination of the resected specimen revealed a 7 × 0.6-cm, whitish, hard mass. The histological analysis showed a well-differentiated G2 leiomyosarcoma. The surgical margins were tumor free, no necrotic area was present, and very few mitoses existed. Cells stained positive for desmin, actin 1A4, and actin HHF-35. All these features were consistent with a low-grade malignancy. The appendix had no signs of inflammation. Postoperatively, the patient underwent a total-body CT scan that failed to show either residual or distant disease. No adjuvant protocol was deemed necessary. At the 18-month follow-up, the patient is doing well and is disease free.

DISCUSSION

Leiomyosarcomas, a rare malignancy of smooth muscle cell origin, may arise from the retroperitoneum and present with the same vague symptoms as those of malignancies in the pelvic organs. Surgery is as crucial to the treatment of this neoplasm as it is to other soft tissue sarcomas. Although multimodal treatment modalities have been reported to achieve local control, surgical resection of the primary tumor is necessary.[4-7] The oncologic surgical principles to comply with are en bloc excision of the tumor and confirmation of tumor-free margins.[6-8] Complete tumor excision remains a challenge even for experienced surgeons.5 In the international literature, consisting mainly of case reports and few small series, resectability ranges from 38% to 100%, radicality from 8% to 95%, and survival rates from 0% to 29%.[1-10] Node metastases are extremely rare (less than 1% of reported cases), and nodal status does not seem to play a relevant prognostic role. Local recurrence is very common (33% to 86%), and distant metastases are rare (up to 30%), with local failure being the usual cause of death.[1-10]

Herein, we have reported on a case of retroperitoneal leiomyosarcoma, mimicking acute appendicitis. A 37-year-old woman was admitted to our institution with a suspected diagnosis of acute appendicitis. At laparoscopy, a retroperitoneal mass was found below the cecum and the appendix. Once the parietal peritoneum was incised, it appeared encapsulated and well cleaved from all the surrounding structures. The histology analysis showed a retroperitoneal G2 leiomyosarcoma with tumor-free margins. At a 18-month follow-up, the patient was disease free. No adjuvant chemotherapy, radiotherapy, or both together were administered.

CONCLUSION

Surgery is the main therapeutic option for resectable RLMS. The current report describes the laparoscopic approach to an incidentally discovered, small and well encapsulated RLMS. In such a case, laparoscopy yielded a high potential for diagnosis and treatment, as well as the advantages of minimally invasive surgery, including the possibility of a second-look procedure when necessary.