Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) of the pancreas: second case report.

INTRODUCTION: Rosai-Dorfman disease (RDD), originally described as sinus histiocytosis with massive lymphadenopathy, is a rare histiocytic proliferative disorder with a distinctive microscopic appearance. It formerly was thought to be a process limited to lymph nodes, yet RDD has been documented to occur in many organ systems, notably the bone, skin, soft tissue, central nervous system, eye and orbit, and upper respiratory tract. The digestive system, however, is affected only exceptionally, with this being only the second documented case involving the pancreas. CASE DESCRIPTION: In this case report, we present a case of a 63-year-old African-American female who was found to have a pancreatic head mass and right middle lobe pleural nodule during evaluation for obstructive jaundice. DISCUSSION AND
CONCLUSION: She underwent a Whipple procedure. Her pathology of both the pancreatic mass and RML lung wedge resection showed sinus histiocytosis with massive lymphadenopathy, along with extensive fibrosis intertwined with nodular mixed inflammatory infiltrate. The histiocytes characteristically showed "emperipolesis," in which lymphocytes had penetrated the cytoplasm and remained viable within the histiocytes (lymphocytes continued to have free movement in the histiocyte). In addition, the histiocytic cells were positive with S-100 protein and CD68, hallmarks of RDD. Although rare, Rosai-Dorfman disease should be considered in the differential diagnosis of patients presenting with pancreatic and/or lung nodules, especially when biopsy or cytology results report atypical inflammatory findings.