Fatal case of pancreatic panniculitis caused by occult neuroendocrine tumor in the corresponding organ: A case report and review of the published work

Pancreatic panniculitis (PP) is a rare clinical variant of subcutaneous fat necrosis, developing in patients with a variety of pancreatic diseases such as acute or chronic pancreatitis, tumors and cysts. The tumor-associated PP represents a noteworthy skin manifestation of underlying internal malignancies, also known as dermadrome. Among causative pancreatic tumors, acinar cell carcinoma is the most frequent malignancy; however, little is known about how the origin of tumor cells and progression stage of pancreatic tumors potentially contribute to the establishment of panniculitis. Here, we present a 69-year-old Japanese male case of clinically aggressive PP on the bilateral legs, whose skin lesions developed prior to the diagnosis of occult pancreatic tumor and liver metastasis. Moreover, the immunopathology of the pancreatic lesion revealed neuroendocrine tumor (NET), a rare pathological variant. Skin lesions immediately spread to the upper limbs with extensive ulcerations and necrosis, accompanied by high levels of serum lipase and elastase, but not with other pancreatic enzymes. He died 2 months after the initial development of the skin lesion due to rapid deterioration of general condition. We reviewed 14 cases, including ours, of PP with NET in the pancreas thus far reported, to identify the clinicopathological characteristics regarding to what extent this rare complication could reflect the clinical course of pancreatic tumors and overall prognosis. Our published work review found that the disease has a significant male predominance (male : female, 13:1) and cases with occult pancreatic tumors died within 4 months after the development of their skin lesions. Our case was the poorest prognostic outcome. This report emphasizes that dermatologists should recognize PP with NET, reflecting a fatal prognosis, and to make a prompt diagnosis.