Secondary torsion of vermiform appendix with mesoappendiceal lipoma

Abstract

A torsion of the vermiform appendix with a mesoappendiceal lipoma is a rare condition. It is also a rare cause of acute abdomen, as such, the condition is diagnosed during surgery. This case report presents a 70-year-old male patient with lower right abdominal pain and signs of acute abdomen with an increased peripheral blood leukocyte count. An ultrasound examination revealed a mass of 9×6 cm², which was suggested to be a perityphlitic abscess. An emergency operation was indicated, as the patient had clinical signs of acute abdomen. Laparotomy via a pararectal incision revealed the cause of the pain to be a torsion of the vermiform appendix caused by a mesoappendiceal lipoma. The apex of the appendix was perforated, which caused circumscript peritonitis. Both an appendectomy and an extirpation of the tumor were performed, and a surgical drain was placed in the wound, yielding an excellent postoperative clinical outcome.

Acute appendicitis is one of the most common causes of acute abdomen. A torsion of the appendix can be primary or secondary, and it is also a rare cause of acute appendicitis.¹ Primary torsion may be the result of obstruction of the appendiceal lumen by foreign bodies, lymphadenitis, or calcified faecal deposits known as fecalith.² Ischemia, necrosis, and luminal dilatation may be evident without primary lesions.³ Contributing factors may include a long appendix, a narrow base, and a laterally attached appendix to the caecum.^4,5 A torsion of the appendix was first described in 1918.³ To date, about 17 cases of secondary torsion have been reported. Documented cases exist where the secondary torsion of the appendix was caused by a carcinoid tumor,⁶ appendiceal mucoceles,^7–9 mucinous cystadenomas,¹⁰ including 1 case of cystadenoma that mimicked ovarian torsion,¹¹ and only 1 case where a torsion was caused by a mesoappendiceal lipoma, which dates back to 1969.¹²

In this case report, a secondary torsion of the vermiform appendix was caused by a mesoappendiceal lipoma, clinically manifested as acute appendicitis.

CASE

A 70-year-old male patient was admitted to the emergency department complaining of abdominal pain in the right lower abdominal quadrant, which began 48 hours prior to arrival. The patient negated vomiting, stool was regular, and there was no significant medical history. A physical examination revealed a pulse of 80 beats/min and a blood pressure reading of 170/100 mm Hg, but this reading normalized later. Rectal and axillary temperatures were measured, yielding measurements of 37.9°C and 37.3°C, respectively. In the right lower abdominal quadrant, a mass was palpated with direct and rebound tenderness. The patient exhibited pain at the McBurney point upon palpation. Rovsing sign and Blumberg sign, as well as the psoas sign, were positive. The patient presented abdominal guarding, or défense musculaire, as a sign of peritoneal irritation. Peripheral blood testing showed an increased leukocyte count (13.9×10⁹/L). Biochemical test results showed no significant values. Abdominal X-rays did not reveal intestinal dilatation or pneumoperitoneum. An ultrasound examination was performed and showed a mass of 9×6 cm² in the right lower abdominal quadrant. Radiologists suggested that the mass may be a perityphlitic abscess. As the patient presented abdominal guarding, a clear sign of acute abdomen, an emergency laparotomy was performed via a pararectus incision. The exploration of the peritoneal cavity revealed a tumor located within the mesenterium of the vermiform appendix. It was clear that this tumor caused the torsion of the appendix, and as a result, inflammation and perforation at the apex, manifested as the signs and symptoms mentioned earlier. A small amount of intestinal content was present in the peritoneal cavity, which was taken for cytological and bacteriological testing. No malignant cells were found. Escherichia coli was isolated, and an antibiogram was ordered. The tumorous mass was 9 cm in length, 6 cm in width, and originated in the mesenterium of the appendix (Figure 1). The appendix was twisted 1800 clockwise, and necrotic due to ischemia. An appendectomy was performed, and the tumor was extirpated (Figure 2). The tumor was sent for pathohistological examination, which identified the tumor as a lipoma. The pathohistological report described the presence of tumorous, maturated adipocytes, and areas of hemorrhage within the lipoma, as well as perivascular inflammatory cell infiltration in the mesenterium, necrotic cell death in the subserosal tissue of the appendix, and perforation at the apex. The findings were plausible with the torsion. The postoperative course was uncomplicated. The patient received antibiotics, cephasoline (1 g, 2 times a day) in combination with metronidazolum (500 mg, 3 times a day), according to the antibiogram results. The patient was in a good physical condition and afebrile. The wound healed per primam. The surgical drain was removed on the third day, and the stitches on the tenth day after surgery. The patient was discharged 5 days after surgery in a good condition.

Figure 1.

Lipoma that caused the torsion of the vermiform appendix. The picture was taken during the operation.

Figure 2.

Extirpated lipoma and vermiform appendix. Necrotic changes, as a result of ischemia, are seen on the lipoma and vermiform appendix.

DISCUSSION

A torsion of the appendix is a very rare condition. Primary torsion is more common than secondary torsion, and it is generally found during abdominal surgical procedures. Primary torsion manifests as acute appendicitis, and a final diagnosis cannot be made without surgery.^1,3 Secondary torsion is rare in practice, and there are even less published reports on it. In general, patients complain of right lower abdominal pain, while nausea or vomiting are usually present.³ In this case report, a secondary torsion is presented of the vermiform appendix that was caused by a mesoappendiceal lipoma. However, no obvious explanation for the mechanism of torsion could be given. Some authors proposed that the torsion of appendix is probably a result of enlargement of the distal end of the organ or the enlargement around it.¹³ The patient in this case showed signs of abdominal pain and acute abdomen indistinguishable from acute appendicitis, which was further characterized as a mild inflammatory response by a white blood cell count. Upon admittance to the hospital, a physical examination was done, including rectal and axillary temperature measurement, as in most cases of peritonitis, there is usually a difference greater than 1°C between rectal and axillary temperatures. This is not a sensitive or certain sign,¹⁴ and was not presented in the patient in this case. There is no exact preoperative examination for a torsion of the appendix, thus diagnosis is only possible during surgery.¹⁵ Even the radiologists associated with this case, based on a preoperative ultrasound examination, suggested an abscess following acute perforated appendicitis, otherwise known as a perityphlitic abscess, instead of a torsion. As the patient presented signs of acute abdomen, an indication for an emergency operation, a laparotomy was performed without any additional preoperative diagnostic procedures. A pararectal incision was used as an approach to abdominal exploration, as it is a large muscle sparing incision that allows for adequate access to explore and to perform a lavage of the peritoneal cavity.¹⁶ Through this incision, a right hemicolectomy may be done; however, in this case, there was no indication for such a procedure as the tumor was benign and well encapsulated, showing no signs of infiltration, and could be treated by a simple and more sparing operation, such as the appendectomy and extirpation of the tumor performed. The exploration of the peritoneal cavity indeed revealed that the patient had circumscript peritonitis, and a surgical drain in the wound was indicated. A torsion of the appendix is a rare cause of acute abdomen, but it must be treated by appendectomy, in a timely manner, to avoid complications, and to achieve an excellent outcome.^2,5

In conclusion, a torsion of the vermiform appendix is a rare cause of acute appendicitis. Its presentation is variable, making preoperative diagnosis extremely difficult. It is treated by appendectomy. Although this condition is not common, it is important to keep it in mind and take it into consideration before surgery.