Subcutaneous fat necrosis, a type of panniculitis, is a rare entity that is manifested by painless or painful subcutaneous nodules on the legs, buttocks, or trunk and is associated with pancreatitis or carcinoma of the pancreas, either of which may be asymptomatic. The histopathological findings are pathognomonic and consist of subcutaneous focal fat necrosis and "ghost-like" cells with thick, shadowy walls and no nuclei.
Arthritis, particularly of the ankles, is a commonly associated finding. Distant foci of fat necrosis in pancreatic disease are probably due to the local action of hematogenous-borne trypsin and lipase. Since the underlying pancreatic disease may be asymptomatic, histopathologic study of all cases of panniculitis should be considered.
Hughes PSH, Apisarnthanarax P, Mullins JF. Subcutaneous Fat Necrosis Associated With Pancreatic Disease. Arch Dermatol. 1975;111(4):506-510. doi:10.1001/archderm.1975.01630160096013