1303 More Than Meets the Eye: Pancreatic Panniculitis as Presenting Sign of Invasive Pancreatic Adenocarcinoma

Abstract

INTRODUCTION: Despite its first description by Chiari in 1883, pancreatic panniculitis remains an atypical manifestation of pancreatic disease, appearing in only 0.3-2% of patients. Although the pathogenesis remains unclear, biopsy-proven subcutaneous liquefactive fat necrosis has implicated elevated lipase, amylase, and trypsin in dissemination and subcutaneous deposition/lipolysis, manifesting as edematous, erythematous superficial nodules of the lower extremities, thigh, and buttock. CASE DESCRIPTION/METHODS: A 91-year-old male presented with 2-week history of painful erythematous nodular rash of bilateral anterior lower extremities. Rash began as small singleton lesion, approximately 1 cm each in size, which grew in diameter with progressively worsening tenderness. Outpatient punch biopsy revealed lobular fat necrosis and local inflammatory infiltrate, consistent with pancreatic panniculitis. Labs were significant for amylase 1026 U/L (ULN 100), lipase of 4366 U/L (ULN 78), CA 19-9 1600 U/mL, and CEA of 9.4 ng/mL. CT-abdomen/pelvis without contrast showed a normal appearing liver, atrophic pancreas with 1.5 cm cystic structure at the pancreatic head, and a 9 mm cystic structure within the pancreatic body. EUS/ERCP for suspected choledocholithiasis with concomitant malignancy revealed 5 mm dilation of the main pancreatic duct with associated 21 mm × 17 mm mass of mixed solid and cystic consistency with multiple anechoic lesions throughout the pancreas suggestive of cysts. Fine needle biopsy revealed invasive ductal adenocarcinoma with associated high grade intraductal papillary mucinous neoplasm. He completed staging work-up and underwent Whipple Procedure with negative margins. DISCUSSION: Although a rare dermatologic manifestation of underlying pathology, pancreatic panniculitis serves as a herald of severe pancreatic pathology. Subcutaneous biopsy of suspicious lesions is invaluable in identifying the etiology and ultimately diagnosing underlying pancreatic pathology. Histologic evaluation following punch biopsy of nodules reveals liquefactive fat necrosis, surrounded by a neutrophil-rich mixed inflammatory infiltrate with pathognomonic “ghost cells”. Treatment of the underlying disease process can lead to resolution of the nodules. Our patient presented with pancreatic panniculitis as the initial manifestation of internal occult malignancy in the absence of typical symptoms. Prompt recognition and biopsy of suspicious nodules led to an expedient diagnosis of locally resectable disease.