Which of the following statements about gastric leiomyomas is/are true?

A. They are the most common type of gastric tumor of the stomach at autopsy.

C. A conservative surgical approach is indicated for their resection since regional lymphadenectomy has not been proved reliable even when they turn out to be malignant.

D. Severe hemorrhage may occur from deep ulcerations overlying the intramural tumor.

DISCUSSION: Approximately 40% of benign tumors of the stomach are leiomyomas derived from the smooth muscle of the stomach or its associated blood vessels. Because it is rare for gastric leiomyomas smaller than 3 cm. in diameter to be symptomatic, considerably fewer than 2% of gastric neoplasms resected surgically are of smooth muscle origin. Gastric leiomyomas may be smooth or lobulated, but in time a central ulceration occurs in the mucosal bulge of the tumor in approximately half of submucosal leiomyomas. Ulceration may be present in smaller tumors but absent in very large tumors. Overlying central mucosal ulceration, which may penetrate deeply into the tumor, results in hematemesis, melena, or anemia and draws attention to the tumor. Bleeding from the tumor may be massive and/or intermittent. Gastric leiomyomas are not encapsulated, even though on section they appear to be well-circumscribed. Microscopically, the tumor cells at the margin may intermingle with cells of the surrounding gastric wall. Along with the presence of occasional large cells with hyperchromatic nuclei, this has led to confusion in distinguishing benign tumors from malignant ones. Stout described a reasonably distinct variety of gastric smooth muscle tumor that he called leiomyoblastoma (bizarre smooth muscle tumor). They were characterized histologically by polyhedral smooth muscle cells with central nuclei and abundant cytoplasm rather than elongated cells. A clear zone that surrounds the central nucleus may be an artifact of fixation. Leiomyoblastoma may be benign or malignant. Carney has described a syndrome characterized by the triad of multiple malignant leiomyoblastoma, pulmonary chondroma, and functioning extra-adrenal paraganglioma. The principle of surgical treatment of smooth muscle tumors is local excision with a 2- to 3-cm. margin of surrounding gastric wall. In view of the difficulty in distinguishing between the benign and malignant variants, enucleation is not an appropriate method of treatment. Regional lymphadenectomy is not of proven value, even if malignancy is strongly suspected and is not consistent with the known property of these tumors to spread by the hematogenous route.