Surgical Approach to Sarcoma of the Cecum?
A 52-year-old man had a radical right colectomy for a sarcoma of the cecal wall (high grade of malignancy, 10 cells/field). On a postoperative computerized tomography (CT) scan 2 months later, a 3-cm lenticular lesion was found behind the right kidney. Other clinical and radiologic parameters are normal. Magnetic resonance imaging wasn't helpful and his positron emission tomography scan is normal. What is the best approach to this case?

J.M. Trindade Soares, MD, PhD, FACS

This patient underwent a "radical right colectomy" for a high-grade sarcoma. This was presumably a malignant gastrointestinal stromal tumor (GIST), leiomyosarcoma, or dedifferentiated liposarcoma. The colon is an infrequent site for stromal tumors, accounting for less than 5% of all intestinal stromal tumors.

A CT scan 2 months postoperatively delineated a 3-cm lenticular lesion behind the right kidney. This was performed unusually early in the postoperative period. Presumably this is new and there are no other intraabdominal abnormalities suggestive of recurrence. My radiology colleagues have educated me that the term "lenticular", although not frequently used to describe abdominal findings (usually used o describe abdominal findings in the head), is the shape that is created when subsyance accumulates between 2 less malleable surfaces. Thus, this may represent loculated fluid between Gerota's fascia and the posterior abdominal wall. However, one must consider whether this is a recurrence or perhaps, residual tumor. At the first operation, it is important to know whether the tumor extended towards the posterior aspect of the kidney. If there is a question as to whether this is a recurrence, an image-guided biopsy can be performed, but is not mandatory. In that this is relatively early in the postoperative period and has taken on a lenticular appearance, an image-guided biopsy/aspiration should be considered. If a definitive answer is not obtained and there is no concern of a prior positive margin or proximity to the region of the posterior kidney, then this patient can be followed with a repeat CT scan in 3 months.

If recurrence is confirmed by biopsy or if you decide to explore the patient without a biopsy because of prior margin status, a preoperative chest CT should be obtained. Although the liver is the preferential site for metastases, lung is the second most frequent site. Isolated lung metastases are not an absolute contraindication to abdominal exploration and resection. Pulmonary metastases can then be resected. However, it must be noted that if pulmonary metastases are present, this short disease-free interval is a poor prognostic sign. Last, in light of the proximity to the right kidney and the possible need for nephrectomy, renal function should be determined. If there is compromised renal function, a nephron-sparing nephrectomy can be considered as long as negative margins are obtained.

Thus, an aggressive approach should be taken in the management of this patient. Rendering him disease-free at a second operation will potentially provide him with an enhanced overall survival.