Embolic Metastases

Malignancies shed as many as 4 million cells per gram of tumor tissue into the bloodstream per day. Of these, greater than 90% are cleared rapidly from the circulation.231,232 Despite this "metastatic inefficiency," the abdominal organs and bowel are a common site of he-matogenous metastases from both intraabdominal and

231 232

extraabdominal primary sites. '

The most common primary neoplasms that embolize to bowel include melanoma and tumors of the breast and lung. The presenting picture is usually one of incomplete obstruction or bleeding, often occurring several years after treatment of the original neoplasm. At times, the symptoms of the bowel metastases may be the first clinical manifestation of an occult primary malig-

7,8,233,234

nancy. Partial or complete obstruction is the re sult of the bulk of the metastatic mass, accompanied by either angulation of the bowel from a fibrotic response or intussusception. The appearance of a hematogenous metastasis to bowel depends on the characteristics of the lesions.1 These include both the degree of vascularity relative to the rate of growth and the desmoplastic capabilities.

Fig. 4-197. Demonstration of small seeded deposits by CT after induced pneumoperitoneum, using a "pulmonary-type window."

(a) Pinpoint metastatic ovarian lesions (arrowheads) are detected. Asterisk = ascending colon.

(b) Two ovarian carcinomatous nodular lesions outside the bowel lumen (arrows) are shown. (Reproduced from Caseiro-Alves et al.223)

Fig. 4-197. Demonstration of small seeded deposits by CT after induced pneumoperitoneum, using a "pulmonary-type window."

(a) Pinpoint metastatic ovarian lesions (arrowheads) are detected. Asterisk = ascending colon.

(b) Two ovarian carcinomatous nodular lesions outside the bowel lumen (arrows) are shown. (Reproduced from Caseiro-Alves et al.223)

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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