A Gastrointestinal Stromal Tumor Discovered in a Resected Hemorrhoidal Donut After Stapled Hemorrhoidopexy: Report of a Case

We report a case of a 47-year-old woman found to have a rectal gastrointestinal stromal tumor discovered on routine pathological examination of the resected hemorrhoidal donut after a stapled hemorrhoidopexy. There was no evidence of metastatic spread. No further therapy will be instituted.

Case Report

A 47-YEAR-OLD, HEALTHY FEMALE presented with a 10-year history of painful, itching, and protruding hemorrhoids. Her condition had recently exacerbated, and she desired definitive treatment. Her past medical history was unremarkable except for a history of a previous appendectomy. She was found to have enlarged external hemorrhoids and grade 3 internal hemorrhoids. Digital examination, fecal occult blood exam, and proctosigmoidoscopy to 10 cm were normal. A discussion was held with the patient regarding the various options available to her for treatment. She opted to undergo a stapled hemorrhoidopexy. A routine preoperative history and physical examination was performed and was unremarkable except for a healed appendectomy scar. A CBC, electrolytes, and urinalysis were also within normal limits.

She underwent an uneventful stapled hemorrhoidopexy. On routine intraoperative visual examination of the hemorrhoidal donut, it was noted that there was a small, bulbous, pale yellow swelling on the external aspect of the posterior portion of the donut. The remainder of the donut appeared grossly normal, and it was submitted for pathological examination. The patient tolerated the procedure well and had no postoperative discomfort of any kind and had no complaints referable to her operation. She felt that her symptoms had been completely ameliorated and she has remained asymptomatic since her procedure.

The final pathology report indicated that the previously seen bulbous area was a gastrointestinal stromal tumor. The area was inked and reexamined. The gastrointestinal stromal tumor was seen to measure 0.7 cm in greatest diameter and was completely contained within the fibers of the muscularis propria. It was seen to have been completely excised and had margins that were negative for tumor. Immunohistochemical stains were ordered.

The patient underwent upper gastrointestinal endoscopy, colonoscopy, and a small intestinal capsule study. All were normal. A CT scan of the pelvis was normal except for a small amount of inflammatory change at the resection site. The abdominal CT scan performed with oral and intravenous contrast showed a 2.9 cm 2.7 cm low-attenuation round density in the posterior aspect of the right lobe of the liver. There was delayed phase illumination of the lesion consistent with a diagnosis of an hemangioma. The patient was found to have had a CT scan of the abdomen prior to her appendectomy 2 years earlier. It showed an identical lesion in an identical location. It too had been diagnosed as an hemangioma.

The results of the immunohistochemical stains were now available; They showed that the tumor was strongly positive to C-Kit and CD34 antibody/probe. SlOO, smooth muscle actin (SMA), and desmin probes were negative.

Sections from this specimen showed a 0.7-cm-diameter, well circumscribed, round mass contained within the muscularis propria and abutting normal-appearing mucosa and submucosa (Fig. 1). The mass is composed of interlacing fascicles and whorls of elongated cells seen to form a characteristic storiform pattern (Fig. 2). The cells show pale eosinophilic cytoplasm and bland, hypochromatic, elongated, spindle-shaped nuclei. Many of these nuclei demonstrate a typical “cigar-shaped” appearance. This neoplasm does not show high cellularity or significant mitotic activity (<1 mitosis/10 hpf) (Fig. 3).

Immunohistochemical examination reveals that this neoplasm stains strongly positive for CD34 and C-Kit (CD117) (Fig. 4). Scattered cells show positive staining for desmin and smooth muscle actin, but overall, these stains are interpreted as negative. For all of these immunostains, the adjacent intestinal smooth muscle serves as an excellent control. In contrast to the neoplasm, the adjacent smooth muscle is negative for CD34 and C-Kit. The adjacent smooth muscle shows strong positive staining for desmin and SMA and clearly demonstrates what a positive immunostain for these antigens should look like (Fig. 5). The histological appearance and staining patterns are most consistent with a gastrointestinal stromal tumor (GIST).

FIG. 1. H and E low magnification photomicrograph of tumor.

FIG. 2. H and E 40 magnification photomicrograph of tumor.

FIG. 3. H and E 100 magnification photomicrograph of tumor.

FIG. 4. Positive tumor stain with CD34 and c-kit (CD117).

The patient will be evaluated on a regular basis with physical exams and endoscopic examinations. No further therapy is planned. She remains asymptomatic after her stapled hemorrhoidopexy and is satisfied with her results.

FIG. 5. Positive muscle stain for desmin and SMA (tumor does not stain).

Discussion

Gastrointestinal stromal tumors are uncommon. They are mesenchymal tumors that arise in the wall of the gastrointestinal tract. Accounting for 0.1 per cent to 3 per cent of all gastrointestinal tumors, approximately 150 new cases are diagnosed each year in the United States.1

Gastrointestinal stromal tumors may occur at any location in the digestive tract. They may be found from the esophagus to the anus. Additional locations have been found to include omentum, mesentery, and retroperitoneum.2, 3 They are found in the stomach (52-60%), the small intestine (30%), the colon (11 %), the rectum (7%), and the esophagus (5%).4

Originally thought to be of smooth muscle origin from the intestinal wall, they were referred to as leiomas or leiomyosarcomas. However, more recent studies have suggested that their true origin may be from the intestinal pacemaker cells, and they may contain both neural and muscle appearances. These are also referred to as cells of Cajal.5

After excision, the diagnosis is made by pathological examination, usually showing a highly cellular spindle cell morphology. Alternatively, these tumors may show epithelioid features. Mitotic activity may be active or quiescent. Additionally, most have tyrosine kinase receptors (KIT) and stain positive for these receptors using the CD117 marker (stem cell factor receptor) or CD34.2, 6 Staining with desmin or SMA shows only muscular tissue and leaves the tumor unstained.

Traditionally, treatment has been confined to surgical excision. Complete resection with the avoidance of tumor rupture is the goal of any excision. Rather than growing and invading surrounding organs, these tumors tend to grow by expanding and pushing other tissues away, making complete surgical excision relatively straightforward.7

Sloan-Kettering Cancer Center recently prospectively studied 200 patients with gastrointestinal stromal tumors. Forty-six per cent of patients presented with only an isolated primary tumor and no metastatic disease. Forty-seven per cent first presented with metastatic disease, and 7 per cent of patients presented with a local recurrence after having undergone a previous curative resection. Surgical treatment was the only mode of therapy. In 80 patients with primary tumors, the survival rate was 54 per cent at 5 years. Survival rate decreased to 20 per cent with tumors larger than 10 cm. Five-year survival was predicted by tumor size but not by microscopic margins of resections.8

Until recently, radiation therapy and/or chemotherapy had little to offer in the way of prolonging survival. However, following the discovery that imatinib was able to block c-kit tyrosine kinase9 and lead to growth arrest and eventual apoptosis,10 further studies were begun. Larger studies have now been performed and show promising results, with 59 per cent of 145 patients showing a partial response to 400 mg or 600 mg of imatinib daily. Only 13 per cent showed disease progression.11

With respect to rectal gastrointestinal stromal tumors, in 2001 a retrospective review was reported that examined the clinicopathologic features of 133 anorectal gastrointestinal stromal tumors. Occurring most commonly in adults, who ranged in age from 17 to 90 years (median, 60 years), it was found that there was a male predominance (71%). It was found that the tumors ranged from small, asymptomatic intramural nodules to larger, bulging symptomatic masses. Most were of the highly cellular spindle cell type and most stained positive for KIT and CD34. Size greater than 5 cm and greater than 5 mitoses per 5 high-power fields (hpf) were associated with a 70 per cent mortality rate. There was a long time period between the primary operative excision and the discovery of recurrences or metastases. Local recurrence or metastatic disease occurred in 54 per cent of patients. Metastatic sites included liver, bones, or the lungs.12

When discovered, treatment is primarily by wide excision (and abdominoperineal excision if necessary).

To our knowledge, our patient represents the first reported case of a complete excision of a previously asymptomatic and undiscovered anorectal gastrointestinal stromal tumor found during the conduct of a stapled hemo\rrhoidopexy. A metastatic evaluation has been negative, and the patient will be followed closely with regular radiographic and endoscopic screening.

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12. Miettinen M, Furlong M, Sarlomo-Rikala M, et al. Gastrointestinal stromal tumors, intramural leiomyomas, and leiomyosarcomas in the rectum and anus: a clinicopathological, immunohistochemical, and molecular genetic study of 144 cases. Am J Surg Pathol 2001;25:1121-33.

EIMAN FIROOZMAND, M.D., F.A.C.S.,* SCOTT BINDER, M.D., F.A.C.P.,[dagger] ANDREW THOMPSON, M.D., PH.D.,[dagger] GARY H. HOFFMAN, M.D., F.A.C.S.*

From the * Department of Surgery, Cedars Sinai Medical Center, Los Angeles, California; and [dagger] UCLA Medical Center, David Geffen School of Medicine, Los Angeles, California

Address correspondence to Gary H. Hoffman, M.D., F.A.C.S., 9400 Brighton Way, Suite 307, Beverly Hills, CA 90210.

Copyright The Southeastern Surgical Congress Feb 2005