Sixty-six cases of leiomyosarcoma of the inferior vena cava (IVC) have been reported. We present another case and review the characteristics and treatment of this rare tumor. IVC leiomyosarcomas spread by extension into adjacent tissue planes. Direct extension into the heart is known, but not into the kidneys, adrenals, or bowel. IVC leiomyosarcomas arising below the renal vein cause pain in the right-lower quadrant, back, and flank, and varying degrees of lower extremity edema; those arising in the middle caval segment cause right-upper-quadrant pain and sometimes renovascular hypertension; those arising above the hepatic vein cause varying manifestations of the Budd-Chiari syndrome. A reasonable approach to early diagnosis involves oral and intravenous contrast studies followed by computed tomography, angiography, and vena cavography. Aggressive surgical treatment is optimal in light of the tumor's slow growth pattern and relatively low malignant potential. (Metastases have been reported in fewer than 50% of cases). Tumors involving the lower IVC are most amenable to surgery; extensive collateral venous drainage of the left kidney preserves renal function during resection of middle caval tumors. Upper caval leiomyosarcomas are the least amenable to complete removal. Postoperative survival of all patients has ranged from a few weeks to eight years.

A review of 308 cases of colorectal carcinoma showed 12 cases (3.9%) of colorectal multiple primary malignant tumors and 14 cases (4.5%) of colorectal primary malignant tumor associated with extracolonic primary malignant tumor. A total of 60 tumors was involved: 14 each in the sigmoid and transverse colon; eight in the cecum; six in the rectum; one each in the ascending and descending colons; three each in the bladder and prostate; two each in the breast, cervix, and lung; and one each in the skin, nasopharynx, kidney, and endometrium. Three of the four patients with multifocal cancer were found to have in situ cancer, and 12.7% of concomitant adenomas had malignant changes. Seven patients had regional lymph node metastases. Of the six patients with rectocolonic multiple tumors who had adequate follow-up data, survival in three ranged from 19.5 to 60 months; three were alive and well 15 to 51 months after resection. Survival of patients with primary rectocolonic and extracolonic tumors was similar. From these data and the pathologic study of the resected specimens, we recommend for any patient with cancer of the rectocolon that the entire colon be searched for multiple primary malignant tumors, that extracolonic tumors be considered second primary tumors unless proved to be metastases, and that follow-up be long and include frequent rectocolonic examinations for a second primary tumor.