Peritoneal loose bodies may be discovered incidentally during laparotomy or at autopsy. Most of the reported cases are adults but the condition may be diagnosed at younger ages and children. The size is usually small not exceeding a size of a pea1.
In most patients they cause no symptoms or nonspecific symptoms. There may be mild abdominal pain but large size masses may produce urinary frequency or retention, constipation, intestinal obstruction, abdominal distension or may become palpable during abdominal examination1,2.
They usually consist of densely hyalinized, laminated, fibrous tissue which is arranged in multiple concentric layers2.
The differential diagnoses of peritoneal loose bodies may include calcified uterine fibroid, calcifying fibrous peritoneal pseudotumor, foreign body granuloma, teratoma, ovarian cancer, desmoid tumor, spontaneously amputated ovary, enlarged mesenteric lymph node, peritoneal tuberculosis, and hydatid cyst. Calcified leiomyoma of the uterus and calcifying fibrous peritoneal pseudotumor are the most difficult to be distinguished from loose bodies. Immunohistochemical studies are sometimes very helpful in distinguishing some different types of these lesions1,3–6.
Imaging, particularly magnetic resonance imaging (MRI) shows that peritoneal loose bodies have a low intensity signals in both T1 and T2 weighted images, it will also shows the same signal intensity as in muscle or collagen tissues, other modalities such as ultrasound is not usually diagnostic. Computed tomography (CT)-scan shows well defined masses which consist of central or scattered peripheral calcifications1,7.
When the diagnosis is done, no specific form of treatment is usually required, but in selected patients particularly when neoplasm is suspected surgery is required, other indications of surgery may include large symptomatic masses that causes obstruction of the urinary or the alimentary tracts1.
The work has been reported in line with the SCARE 2018 criteria8.
A 67-year-old male presented with lower abdominal pain and constipation for 3 months.
The pain was dull aching in nature and constant in the lower abdomen, associated with constipation, with no vomiting, and no weight loss. The past medical and surgical histories were negative.
The patient had a negative drug history, the family history was not relevant for any genetic or psychosocial abnormalities.
The general examination was unremarkable. Abdominal examination showed a fixed palpable mass in the lower abdomen arising from the pelvic cavity, the mass was firm in consistency and not mobile.
The hemoglobin level was normal, the renal function and the liver function tests were normal.
Ultrasound of the abdomen showed an evidence of 10×70 cm mass lesion in the lower abdomen with calcifications. Other intra-abdominal organs were normal.
MRI of the pelvis showed a large lobulated abdominal mass 10×70 cm with low signal intensity on T1W image, and intermediate signal intensity on T2W image with areas of necrosis and calcifications, there was no significant enhancement (Fig. 1).
Colonoscopy was performed and there it was difficult to pass the scope beyond the sigmoid colon due to external compression by the mass (Fig. 2).
Decision for laparotomy was done, throughput a midline incision, a large smooth and firm intraperitoneal mass was found attached by small pedicle to the omentum (Figs. 3, 4).
Extraction of the mass was performed. The cut surface of the mass showed a light yellow mass with multiple concentric layers and a central stone like structure (Fig. 5).
The histopathologic evaluation revealed an extensive fibrous tissue with mild inflammatory cells infiltration with areas of calcifications (Fig. 6).
The operation was done by a specialist general surgeon, who is specialized in the field of general surgery and laparoscopic surgery.
No specific postintervention consideration was undertaken.
Follow-up and outcomes
The patient was admitted for 3 days after surgery with no complications. Follow-up ultrasound was normal 6 months after surgery.
In most literature, it is reported that these peritoneal loose bodies are originated from epiploic appendices which undergo a sequential process of torsion, ischemia and necrosis, saponification and then calcification, they are termed sometimes as peritoneal mice1.
The most important critical step in the management is to distinguish them from other intraperitoneal lesions particularly tumors which is sometimes very difficult and may require some invasive procedures including surgery1.
Most of the reported cases are small in size ranging from 0.5 to 2.5 cm and only few cases are reported to be larger than 5 cm, in such cases they are termed as giant peritoneal loose bodies, cases larger than 9 cm are very rare and only few cases are reported in literature, in our case the size was 10 cm and probably it is the largest reported size1,7.
Most of the loose bodies are located in the pelvic cavity due to the effects of gravity, the location may change by changing of the position if there are no adhesions7.
The preoperative diagnosis is sometimes very difficult especially the distinction from neoplasms and most cases are diagnosed after the result of histopathology like the presentation in our case4.
Imaging particularly CT-scan may be helpful to differentiate them from some other pathologies which have different contrast enhancement comparing to loose bodies which have a homogeneous texture with no enhancement. MRI show that peritoneal loose bodies have low signal intensity which is near to muscle intensity and collagen tissues which is helpful especially when the CT-scan is not very informative1,4.
Currently, there is no specific form of treatment for peritoneal loose bodies, small size lesions may be left untreated. Large size masses more than 5 cm usually require intervention because most of them are associated with symptoms. Surgery can be done by the open and laparoscopic technique2.
Ethical approval was exempted by my institution for reporting the case.
Sources of funding
The authors are the main source of funding.
The concept of reporting the case, writing and final approval of the manuscript was done by Dr Ayad A. Mohammed.
Conflict of interest disclosures
The authors declare that they have no financial conflict of interest with regard to the content of this report.
Research registration unique identifying number (UIN)
Dr Ayad Ahmad Mohammed.
1. Kim H-S, Sung J-Y, Park WS, et al. A giant peritoneal loose body. Korean J Pathol 2013;47:378.
2. Cojocari N, David L. Giant peritoneal loose body in a patient with end-stage renal disease. SAGE Open Med Case Rep 2018;6: 2050313X18770936.
3. Arif SH, Mohammed AA. Primary hydatid cyst of the urinary bladder. Case Rep 2018;2018:bcr-2018-226341.
4. Jang JT, Kang HJ, Yoon JY, et al. Giant peritoneal loose body in the pelvic cavity. J Korean Soc Coloproctol 2012;28:108.
5. Aldohuky W, Mohammed AA. Fibrous tumor of the stomach causing abdominal pain and melena: case report with review of literature. Int J Surg Case Rep 2019;65:97–101.
6. Ng JL, Salkade HP, Yusof SB, et al. Peculiar case of calcifying fibrous tumor presenting as a free-floating intraperitoneal body. J Case Rep Images Surg 2016;1:29–33.
7. Gayer G, Petrovitch I. CT diagnosis of a large peritoneal loose body: a case report and review of the literature. Br J Radiol 2011;84:e83–5.
8. Agha RA, Borrelli MR, Farwana R, et al. The SCARE 2018 statement: updating consensus Surgical CAse REport (SCARE) guidelines. Int J Surg 2018;60:132–6.