Primary idiopathic segmental infarction and torsion of greater omentum: Report of two cases ROBERT E. FOX, JR., D o Wagoner, Oklahoma the first report of primary torsion of the omentum.2 Primary idiopathic segmental torsion The first description of omental infarction was by and isolated infarction of the greater Johnson in 1932.1 omentum is a rare clinical entity A myriad of terms are used to describe this clini- which is frequently misdiagnosed. cal entity: acute segmental infarction, omental in- The clinical manifestations are farction, omental segmental infarction, spontane- varied, and diagnosis is usually made ous infarction of the greater omentum, hemor- at laparotomy. However, with rhagic infarction of the greater omentum, throm- increased awareness, the correct bosis of the omentum, omental volvulus, and acute preoperative diagnosis might be epiploitis. However, the concensus in the literature made. The presence of lower right indicates the correct term is "primary idiopathic quadrant pain, anorexia, segmental infarction of greater omentum." leukocytosis, and a low-grade fever Anton proposed the following classification: should alert one to the possibility of A. Primary (idiopathic, cryptogenic, pure intra- greater omental infarction. If there is abdominal) a negative exploratory celiotomy and B. Secondary serosanguineous fluid, the greater 1. Hernia (external, in sac) omentum should always be explored 2. Abdominal for a possible torsion and/or a. Intrinsic (cysts and tumors) infarction prior to closing the b. Extrinsic (associated with pathologic abdomen. findings of abdominal and pelvic organs and peritoneum) The next classification was published by Leitner4 in 1952 as follows: A. Omental infarction (with or without gangrene) due to torsion. Primary idiopathic segmental torsion and isolated 1. Primary (idiopathic) infarction of the greater omentum is a rare occur- 2. Secondary rence of an acute surgical abdomen which is fre- B. Omental infarction (with or without gangrene) quently misdiagnosed as acute appendicitis, acute due to thrombosis. cholecystitis, or perforated viscus. It usually is not 1. Idiopathic (spontaneous) infarction. diagnosed until laparotomy. Fortunately, most 2. Associated with vascular disease. cases present with such persistent abdominal 3. Due to external trauma. symptoms that exploratory laparotomy is per- Several cases of omental infarction have been formed. However, one should be suspicious of a reported in the past decade, bringing the total to a "negative" abdomen and explore the "abdominal probable 190 cases, as reflected by a brief review of policemen," that universal metaphor of the greater the English literature. Although it appears to be a omentuml expressed by Rutherford Morrison in rare disease by a number of reports, it is probably teaching his classes. much more common than the literature suggests, Pierre de Marchette is credited with the publica- and is not diagnosed or reported by surgeons be- tion of the first report in 1851 of torsion of the cause of its benign nature. omentum as a separate clinical entity. 2 His report Several classifications have been presented in and others that followed in the literature were of a the literature and two are noteworthy. The first is secondary type of torsion related to preexisting by Anton and associates in 1946, who published an hernias. In 1896 Bush described hemorrhage of the excellent review in which they discussed embryol- greater omentum.3 Eitel in 1899 is credited with ogy, anatomy, physiology, and pathology of the Primary idiopathic segmental infarction and torsion of greater omentum 189/101 omentum, supported by 104 references. turn was detected on the right side and was found to be Wrzesinski,5 in 1956, reported two cases of pri- firm on digital examination. When it was brought down into the operative field it was bluish-red and appeared to mary idiopathic (spontaneous) infarction of the be a pedicle of the omentum that had undergone torsion omentum and proposed the following criteria to and which had an impending infarction. The entire seg- simplify and avoid confusion with the other types of ment was excised and the abdomen closed. secondary infarction: (1) The infarction must be In addition to the appendix, the gross pathologic spontaneous and idiopathic and not preceded by findings included a fragment of fibrofatty tissue, said to trauma, infection, or other etiologic factors; (2) it be the omentum, weighing 12 grams. It measured 6.5 x must be segmental and not associated with massive 2.4 x 1.2 cm. Several of the fatty lobules were dark wine vascular occlusion; (3) it must be primary in the red in color. On cut sectioning the interior of the fatty omentum and not the result of a pathologic condi- mass was a deep red color. The microscopic sections of tion in another organ; and (4) it should present omental tissue revealed normal fat. Recent hemorrhage typical gross and microscopic findings and should was noted in the fat cells. The patients postoperative not have torsion or a pedicle. course was entirely unremarkable, and he was dis- The purpose of this report is to present two cases charged on the fourth postoperative day. and to describe the clinical manifestations to aid in Case two its recognition during surgical evaluation of an A 40-year-old white-man was admitted through the acute abdomen. emergency room with a history of pain for 3 days. It was centered just above McBurneys point in the lower right Case reports quadrant of the abdomen. The patient had no nausea, Case one vomiting, diarrhea, constipation, or cardiopulmonary A 21-year-old white man was admitted through the symptoms (9 months prior he had had two myocardial emergency room with the primary complaint of lower infarctions). There was no history of previous surgery or right abdominal pain. It was intermittent and had in- of trauma or heavy lifting. creased in severity during the preceding 24 hours. The The oral temperature was 98.2 F., the pulse 80 beats patient had pain on ambulation with abdominal splint- per minute and regular, the blood pressure 154/96 mm. ing. He had no nausea, vomiting, constipation, diarrhea, Hg., and the weight 165 lbs. The patient stated that he or anorexia. had a moderate degree of shortness of breath. He had The oral temperature was 99.4 F., the pulse 100 beats smoked for 30 years but had stopped following his per minute and regular, the blood pressure 136/80 mm. myocardial infarctions. He appeared to be well nourished Hg, the height 5, 10", and weight 170 lbs. The patient with slight distress. was well developed and well nourished with moderate to Medical consultation was obtained prior to surgery for marked distress because of the abdominal pain. There cardiac evaluation, which was negative. The impression was no history of trauma or heavy lifting prior to admis- was of atherosclerotic heart disease. Ruptured appendix sion. was ruled out. The abdominal examination revealed obese abdomen, Abdominal examination revealed pinpoint pain on Rovsings sign, negative psoas sign, negative rectal palpation just above McBurneys point and generalized examination, and no evidence of visceromegaly or mas- tenderness in the right lower quadrant. The entire right ses on palpation. On compression and palpation of the side was rigid on deep compression with localized re- abdomen, midplane periumbilical pain was elicited as bound pain. There was no organomegaly or abdominal well as guarding in the right lower quadrant. The re- masses. mainder of the examination was noncontributory and Laboratory examination revealed a leukocyte count of unremarkable. 8,200/cu. mm. with a normal differential. Urinalysis was Laboratory evaluation revealed the following: The normal. SMA-12 revealed elevated cholesterol 316 mg./ leukocyte count was 14,200/cu. mm. with 60 percent 100 ml. (normal range, 150-250 mg./100 ml.). On the day neutrophils, 12 percent stab cells, 25 percent lympho- following admission the EKG, SMA-6, chest x-ray, and cytes, and 3 percent monocytes. Urinalysis was normal. scout abdomen were all unremarkable. A chest x-ray and flatplate of the abdomen were nega- The patient was taken to surgery on the day of admis- tive. sion with the preoperative diagnosis of acute perforated A tentative diagnosis of acute appendicitis was made, appendicitis. Following emergency laparotomy using a and the patient was scheduled for emergency appendec- modified McBurney incision which had to be lengthened tomy. Following laparotomy the appendix was found to both ways, the omentum was found to be adherent to the be retrocecal and subserosal. It was slightly edematous, anterior abdominal wall. It was gently dissected free but otherwise unremarkable, and it was removed in a revealing an infarction of a pedicle of the right side of the routine manner. The appendix would not have accounted omentum with a fibrous strand of omentum attached to for the patients symptoms. Because of the McBurney the pelvis. There was no evidence of inflammatory incision, it was difficult to examine the surrounding changes in the pelvis or elsewhere, with the appendix structures, with the exception of distal small bowel being retroileal. Exploration of the small bowel, which was negative for any pathologic condition. In at- gallbladder, pylorus, stomach, and colon failed to exhibit tempting to palpate the gallbladder, a segment of omen- intrinsic or extrinsic inflammatory changes. The appen- 190/102 Nov. 1979/Journal of AOA/vol. 79/no. 3 dix was removed, the infarcted omentum resected, and and thus theorized that a sudden increase in the abdomen closed. intra-abdominal pressure may result in venous The gross pathologic findings included two fragments rupture and infarction. of fatty tissue, 8 x 6 x 1 cm. and 5 x 2 x 1 cm. Microscopic sections of omentum showed fat with hemorrhage, blood clots, and several small areas of infarction. Comment The patient tolerated the surgery well, the postopera- The two cases reported here each had different tive course was unremarkable, and he was discharged on etiologies and can be placed in different classifi- the fifth postoperative day.