Pancreatic Panniculitis Sans Pancreatitis in a Patient with Diabetic Ketoacidosis.

Dear Editor, A 23-year-old Malay woman with no past medical illness was admitted for a 4-day history of epigastric pain, vomiting and drowsiness. Investigations showed a high anion-gap metabolic acidosis with elevated serum ketones and hyperglycaemia, consistent with diabetic ketoacidosis (DKA). Anti-glutamic acid decarboxylase autoantibodies were positive, consistent with type 1 diabetes mellitus. In the first week of admission, the patient had hyperamylasaemia (670 units/L, upper limit 100 units/L) and hyperlipasaemia (>400 units/L, upper limit 40 units/L) accompanying her epigastric pain, fulfilling the diagnosis of acute pancreatitis.1 The gastroenterology consultant who reviewed the patient, however, requested for contrastenhanced computed tomography (CT) scan of the abdomen to confirm the diagnosis as he felt the patient’s DKA could have accounted for the elevated serum amylase and lipase levels, with similar epigastric pain. Two contrastenhanced CT scans performed 6 days apart were negative for acute pancreatitis. The patient’s hyperamylasaemia and hyperlipasaemia, together with epigastric tenderness, was attributed to DKA by the reviewing gastroenterologist. Two weeks into admission, dermatology consult was sought for a 4-day history of painful lesions over the patient’s legs, associated with bilateral ankles arthralgia. On examination, multiple discrete tender erythematous nodules were present over her shins and dorsal feet (Figs. 1a and 1b). Septic workup was unremarkable. Anti-streptolysin O titre was <200 IU/mL. Serum alpha-1 antitrypsin level was not performed. Clinical differentials considered included pancreatic panniculitis, erythema nodosum, erythema induratum, other causes of panniculitis, and cutaneous polyarteritis nodosa. A 6 mm punch biopsy was performed over one of the patient's right leg nodules. Histology showed lobular panniculitis with fat necrosis and neutrophils. Bluish saponified fat, basophilic deposits of calcium and ghost cells were present. No vasculitis was seen (Fig. 2). This was consistent with pancreatic panniculitis. No tissue was sent for direct immunofluorescence. The patient was treated with indomethacin 25 mg thrice a day for symptomatic relief of her painful leg nodules. On outpatient review 2 weeks later, the patient was well. Nodules over her legs were less painful with flattening and post-inflammatory hyperpigmentation changes were seen. The diagnosis of acute pancreatitis requires 2 of the following 3 features: 1) abdominal pain consistent with acute pancreatitis (acute onset of a persistent, severe, epigastric pain often radiating to back); 2) serum lipase or amylase activity at least 3 times greater than the upper limit of normal; and 3) characteristic findings of acute pancreatitis on contrast-enhanced CT and less commonly magnetic resonance imaging (MRI) or transabdominal ultrasonography.1 Fig. 1. A) Multiple erythematous nodules are seen over the patient’s shins and dorsal feet. B) A close-up view of the erythematous nodules over the patient’s right shin.