Recurrent idiopathic lobular panniculitis of the buttocks triggered by prolonged standing

ABSTRACT

Idiopathic lobular panniculitis is a rare inflammatory condition affecting subcutaneous adipose tissue. The diagnosis depends on the histopathological distinction of septal, lobular, or mixed types. Panniculitis is often attributed to autoimmune, infectious, and traumatic causes. However, panniculitis caused by prolonged standing is exceptionally uncommon. We present a case of a 37-year-old previously healthy male experiencing recurrent, self-resolving episodes of painful, hard subcutaneous lumps on the buttocks, consistently induced by standing for more than 8 h. The episodes showed improvement in 3–4 weeks without any intervention. Magnetic resonance imaging (MRI) scans revealed increased T2/STIR signaling and slight edema indicative of inflammatory progression. Ultrasonography of the soft tissues revealed an echo pattern characteristic of a lipoma. The patient was managed with trigger avoidance and remained stable during follow-up. This case demonstrates how mechanical factors can trigger localized fat inflammation, emphasizing the importance of MRI and ultrasonography as a noninvasive diagnostic tool for idiopathic panniculitis.