Introduction

Liponecrotic granuloma, also known as encapsulated fat necrosis, is a benign lesion resulting from a chronic inflammatory reaction of adipose tissue following adipocyte damage [1]. It may be associated with endogenous or exogenous lipids and primarily involves the subcutaneous tissue. This entity most commonly occurs after trauma, surgery, or local ischemia, leading to fat necrosis followed by a granulomatous inflammatory response and progressive fibrosis [1,2].

Clinically, it usually presents as a palpable subcutaneous mass, although most lesions remain small and asymptomatic. In some cases, however, encapsulated fat necrosis may progressively enlarge and present as a tumor-like mass months or even years after the initial triggering event [2]. Because of its variable clinical and radiological presentation, the diagnosis can be challenging and may mimic a soft-tissue neoplasm. Imaging, particularly ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), plays a key role in lesion characterization and diagnostic orientation.

We report a case of a giant post-traumatic liponecrotic granuloma of the gluteal region presenting as a slowly enlarging pseudotumoral soft-tissue mass. Rather than emphasizing the anatomical location itself, this report highlights the diagnostic challenge posed by an unusually large encapsulated lesion with imaging features overlapping those of soft-tissue neoplasms. It also illustrates the complementary value of ultrasound, CT, and MRI in supporting a confident presumptive diagnosis based on characteristic clinicoradiological findings, thereby helping to avoid unnecessary invasive procedures.