An Atypical Abdominal Presentation of Pancreatic Panniculitis in a Patient With Suspected Pancreatic Cancer: A Case Report.

Pancreatic panniculitis (PP) is an uncommon manifestation of pancreatic disorders and usually presents as painful erythematous subcutaneous nodules involving the lower extremities. We describe a 79-year-old man with a pancreatic head tumor clinically suspected to represent pancreatic cancer who developed a painful, erythematous, approximately 10-cm abdominal wall lesion. Contrast-enhanced computed tomography showed inflammatory changes involving the subcutaneous and abdominal wall adipose tissue. Despite the extensive lesion, pancreatic enzyme elevation was modest, with a lipase level of 157 IU/L and pancreatic amylase level of 86 IU/L. Malignant involvement and soft-tissue infection were initially considered because of the lesion's location and appearance. Histopathological examination demonstrated lobular panniculitis, fat necrosis, and anucleated adipocytes with thickened borders and eosinophilic material, consistent with ghost-like adipocytes of PP. Klebsiella pneumoniae was isolated from the aspirated material, raising the possibility of secondary bacterial infection. Cefmetazole was administered at 1 g twice daily for five days; subsequent susceptibility testing showed cefmetazole resistance. After the histopathological diagnosis of PP was established, symptomatic treatment with oral loxoprofen was initiated. The pain, erythema, and swelling gradually improved, and the lesion had markedly resolved by day 60, with corresponding improvement of the abdominal wall inflammatory changes on follow-up computed tomography. This case illustrates that PP may occur at an atypical abdominal site despite only modest pancreatic enzyme elevation and may mimic infection or malignant involvement. Histopathological evaluation of a subcutaneous lesion can be particularly valuable when clinical and biochemical findings are atypical, and a definitive pathological diagnosis of the underlying pancreatic lesion is not obtained.