Compurerized Medical Imaging and Graphics, Vol. 14. No. 6. pp. 431L435, 19W Printed in the USA. All rights reserved.

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LEIOMYOMA INVOLVING THE GASTROCOLIC LIGAMENT: CT DEMONSTRATION

Philip Goodman, Bharat Raval, Carmen Bonmati and Waldemar A. Schmidt’ Departments of Radiology and Pathology and Laboratory Medicine’, The University of Texas Medical School at

Houston, 6431 Fannin, Houston, TX 77030

(Received 15 December 1989)

Abstract-A case of a large leiomyoma involving both the transverse colon and the greater curvature of the stomach is presented. Computed tomography (CT) demonstrated contiguous extension of the mass along the gastrocolic ligament. Although similar findings have been described in colonic and gastric carcinoma and in omental metastases, tbis is the first report in which these findings were due to a leiomyoma.

Key Words: Leiomyoma, Omentum, Stomach, Colon, Computed tomography

INTRODUCTION

The gastrocolic ligament represents an important path- way for the direct extension of malignancy between the transverse colon and the greature curvature of the stom- ach (1, 2). Omental metastases may also invade the colon and stomach along this mesenteric reflection (3-5). We recently encountered a case in which a leiomyoma extended along the gastrocolic ligament to involve both the colon and the stomach. We describe the case briefly and discuss its significance.

CASE REPORT

A 36-year-old woman presented with a two week history of a firm, nontender mid-abdominal mass and increasing constipation. History and physical examina- tion were otherwise noncontributory.

Ultrasound demonstrated a 6 cm, well defined solid mass in the mid-abdomen a.djacent to the inferior aspect of the stomach. The mass was separate from the uterus and ovaries which appeared normal. Since the origin of the mass was uncertain, a CT was performed. This showed a homogeneous mass extending from the stom- ach to the mid-transverse colon (Fig. 1). On a subse- quent barium enema, there was persistent mass effect with tethered folds at the superior aspect of the mid- transverse colon (Fig. 2). This deformity was unrespon- sive to intravenous administration of 1 mg of glucagon. An upper endoscopy revealed no abnormalities in the stomach.

Please address all correspondence to: Philip Goodman, M.D., Department of Radiology, University of Texas Medical Branch, Galveston, TX 77550.

At exploratory laparotomy, there was a large mass attached to the external surface of the mid-transverse colon. The mass involved a large portion of the gastro- colic ligament and was adherent to a focal area of the greater curvature of the stomach. Omental dissection and partial colonic and gastric resections were necessary to mobilize the mass.

Pathologic examination revealed a solid homogeneous mass firmly adherent to a 6 cm segment of colon and a 0.8 cm wedge of stomach (Fig. 3). There was infiltra- tion of the serosal and outer muscular layers of both colon and stomach, and the colonic mucosa, though not invaded, was puckered near the mass. The gastric mucosa appeared unremarkable. The mass contained no hemorrhage, necrosis, or calcification and was well demarcated from adjacent gastrocolic ligament adipose tissues. Exhaustive microscopic exam revealed no cyto- logical evidence of malignancy and was consistent with a leiomyoma of uncertain origin (Fig. 4). The patient made an uneventful recovery.

DISCUSSION

The greater omentum is a fatty peritoneal membrane which extends inferiorly from the greater curvature of the stomach to drape over the small bowel (3). The proximal portion of the greater omentum is known as the gastrocolic ligament. This inserts on the transverse colon at the tenia omentalis, the most anterosuperior of the three longitudinal muscle bands or teniae of the colon, and extends along the superior aspect of the transverse colon between the tenia omentalis and the more posterior tenia mesocolica (4). By direct extension along this ligament, gastric carcinoma can invade the transverse colon and carcinoma of the transverse colon

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432 Computerized Medical Imaging and Graphics November-DecemberIl990, Volume 14, Number 6

Fig. la. CT scan shows a large homogeneous mass (arrows) adjacent to the greater curvature of the distal stomach (curved arrows).

can invade the stomach (1, 2). Metastases to the gastro- colic ligament resulting from intraperitoneal spread of tumor can also invade the stomach, the transverse colon, or both (2-5). However, to our knowledge, such an occurrence secondary to a leiomyoma has not been previously reported.

Leiomyomas are benign smooth muscle tumors that may arise in any portion of the gastrointestinal tract. These occur most commonly in the stomach with de- creasing frequency in the small bowel, esophagus, and colon, respectively. Symptoms vary with size and loca- tion of the mass and may include hemorrhage or ob-

Fig. lb. A more caudal section shows the most inferior portion of the mass (arrow) adjacent to the transverse colon (open arrows).

The g&rocolic ligament 0 P. GOODMAN et al. 433

Fig. 2. Barium enema demonstrates mass effect and tethered folds in the mid-transverse colon (arrows).

struction (6). Although gastric leiomyomas are most often submucosal or intramural in location, subserosal lesions may occur, sometimes attaining large size before

causing symptoms. Such exogastric lesions may extend into the greater or lesser omentum, lesser sac, or general peritoneal cavity (7). Colonic leiomyomas represent less than 3% of intestinal leiomyomas and usually occur in the cecum or rectosigmoid area (6, 8). Primary leiomy- omatous tumors of the omentum are extremely rare though they represent the most common group of pri- mary solid omental tumors (9).

On CT, leiomyomas are usually well marginated and homogeneous in density, unlike their malignant counter- parts, leiomyosarcomas, which tend to be larger, more poorly circumscribed and more heterogeneous in density due to necrosis. Although benign lesions are sometimes very large and necrotic on CT, large malignant lesions almost never appear homogeneous (10-12). Leiomyo- blastoma, a rare smooth muscle neoplasm composed predominantly of rounded cells, may be benign or malignant and may simulate leiomyoma or leiomyosar- coma radiographically ( 13).

The large size and extensive contiguous spread of the mass reported here are not typical features of a leiomy- oma. However, its homogeneous and well defined ap- pearance on CT and absence of cellular atypia on microscopic examination are consistent with a benign lesion.

Although the exact origin of the leiomyoma in our case is uncertain, its extent was clearly demonstrated on CT. Radiologists should be aware that a leiomyoma may spread along the gastrocolic ligament and lead to find-

Fig. 3. Surgical specimen shows a large mass (arrow) with adherent portions of colon (curved arrows) and stomach (open arrow).

434 Computerized Medical Imaging and Graphics NovemberDecember0990, Volume 14, Number 6

Fig. 4. Photomicrograph of the mass shows a uniform population of spindle ceils. (Hematoxylin and eosin, x 2.50.)

ings on CT which can mimic colonic or gastric carci- noma or omental metastases. \

SUMMARY

A case of a leiomyoma extending along the gastro- colic ligament to involve both the stomach and the colon is presented. This rare occurrence may mimic primary or metastatic carcinoma involving the gastrocolic liga- ment.

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REFERENCES

Meyers, M.A. Intraperitoneal spread of malignancies and its effect on the bowel. Clin. Radiol. 32:129-146; 1981. Levitt, R.G.; Koehler, R.E.; Sagel, S.S.; Lee, J.K.T. Metastatic disease of the mesentery and omentum. Radiol. Clin. North Am. 20:501-510; 1982. Cooper, C.; Jeffrey, R.B.; Silverman, P.M.; Federle, M.P.; Chun, G.H. Computed tomography of omental pathology. J. Comput. Assist. Tomogr. 10:6266; 1986. Krestin, G.P.; Beyer, D.; Lorenz, R. Secondary involvement of the transverse colon by tumors of the pelvis: Spread of malignan- cies along the greater omentum. Gastrointest. Radiol. 10:283- 288;1985. Rubesin, S.E.; Levine, M.S.; Glick, S.N. Gastric involvement by omental cakes: Radiographic findings. Gastrointest. Radiol. 11: 223-228; 1986. Simmang, C.L.; Reed, K. Leiomyomas of the gastrointestinal tract. Milit. Med. 15445-47; 1989. Herlinger, H. The recognition of exogastric tumours. Report of six cases. Br. J. Radiol. 39:25-36; 1966. Bruneton, J.N.; Drouillard, J.; Roux, P.; Lecomte, P.; Tavemier, J. Leiomyoma and leiomyosarcoma of the digestive tract-A report of 45 cases and review of the literature. Europ. J. Radiol. 1:291-300; 1981.

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Schwartz, S. I. Principles of surgery, 4th edition. New York McGraw-Hill; 1984. Megibow, A.J.; Balthazar, E.J.; Hulnick, D.H.; Naidich, D.P.; Bosniak, M.A. CT evaluation of gastrointestinal leiomyomas and leiomyosarcomas. Am. J. Roentgenol. 144727-731; 1985. Scatarige, J.C.; Fishman, E.K. ; Jones, B.; Cameron, J.L.; Sand- ers, R.C.; Siegelman, S.S. Gastric leiomyosarcoma: CT observa- tions. J. Comput. Assist. Tomogr. 9:320-327; 1985. McLeod, A.J.; Zomoza, J.; Shirkhoda, A. Leiomyosarcoma: Computed tomographic findings. Radiology 152:133-136; 1984. Stanley, J.H.; Ravenel, D.; Parker, T.H.; Vujic, I. Exogastric leiomyoblastoma: A rare gastric neoplasm mimicking left hepatic mass on computed tomography. J. Comput. Tomogr. 10: 187- 190; 1986.

About the Author--PHILIp GOODMAN was born in Binghamton, New York in 1954. He received his B.A. degree from Cornell University in 1976 and his M.D. degree from the University of Rochester in 1980. He was a resident in diagnostic radiology at Rochester General Hospital in Rochester, New York from 1981 to 1984 and a fellow in gastrointestinal radiology at the Hospital of the University of Pennsyl- vania in Philadelphia during 1986 and 1987. He is currently an Assistant Professor of Radiology at the University of Texas Medical School at Houston, and Chief of Gastrointestinal Radiology at Her- mann Hospital.

About the Author-BmwT RAVAL graduated with a degree in Medicine from Makerere University Medical School in Uganda in 1971. He undertook internship and residency training at St. Michael’s Hospital in Toronto. Currently, he is a Professor of Radiology at the University of Texas Medical School at Houston and Chief of Body Computed Tomography at Hermann Hospital. His interests and publi- cations are in the fields of computed tomography and magnetic resonance imaging of the abdomen.

About the Author-Wmmm A. SCHMDT is a Professor of Pathol- ogy and Laboratory Medicine at the University of Texas Medical School in Houston. He is a graduate of the Oregon Health Sciences University. Presently, he is Director of Cytopathology and Flow Cytometry.

The gastrocolic ligament 0 P. GOODMAN et al. 435

About the AI&OT-CAFMEN M. E~ONMA~ is an Assistant Professor of Radiology at the University of Texas Health Science Center at Houston Medical School, and is currently serving as the Interim Director of Clinical Magnetic Resonance Imaging Division. She is a graduate of Universidad Complutense, Madrid, Spain, and completed

her residency in Radiology at the University of New Mexico School of Medicine in Alburquerque, New Mexico. She has also completed a Clinical fellowship in Abdominal Imaging at the University of Texas Health Science Center at Houston.