A giant peritoneal loose body

Abstract

Peritoneal loose bodies (PLBs) are usually discovered incidentally during laparotomy or autopsy. A few cases of giant PLBs presenting with various symptoms have been reported in the literature. Here, we describe a case of a giant PLB incidentally found in the pelvic cavity of a 50-year-old man. Computed tomography revealed a free ovoid mass in the pelvic cavity that consisted of central dense, heterogeneous calcifications and peripheral soft tissue. The mass was an egg-shaped, hard, glistening concretion measuring 7.5×7.0×6.8 cm and weighing 160 g. This concretion consisted of central necrotic fatty tissue surrounded by concentrically laminated, acellular, fibrous material. Small PLBs usually do not require any specific treatment. However, if PLBs cause alimentary or urinary symptoms due to their large size, surgical removal may be recommended. It is essential for clinicians to be aware of this entity and its characteristic features to establish the correct diagnosis.

Keywords: Colon; Loose body; Peritoneum.

Fig. 1

Abdominopelvic computed tomography findings. (A) Axial image shows a large, oval-shaped mass (arrow) consisting of peripheral soft tissue and central dense, heterogeneous calcifications. There is a distinct fat plane separating the mass from the adjacent organs. (B) Sagittal image reveals that the mass (arrow) compresses the bladder wall.

Fig. 2

Gross and histologic findings. (A) Grossly, the mass is an egg-shaped, white-to-pale yellow, hard, glistening concretion, measuring 7.5×7.0×6.8 cm, weighing 160 g, and resembling a boiled egg. (B) The cut surface of the concretion reveals a 1.5 cm diameter central portion of gray-to-yellow, creamy material surrounded by concentrically lamellar structures. (C) Microscopically, the central portion (inset) of the concretion consists of necrotic fatty tissue. (D) The peripheral portion consists of many layers of laminated, acellular, fibrous material. (E) Scattered blue-to-black lakes of microcalcifications are also identified in the peripheral portion. (F) Masson's trichrome staining shows intensely staining collagen at the periphery.