Sinus histiocytosis with massive lymphadenopathy in the medial cuneiform bone: A case report

Abstract

Introduction: Sinus histiocytosis with massive lymphadenopathy (SHML), also known as Rosai-Dorfman disease, is a benign histiocytic disorder most commonly found in young adults. Bone involvement is rare and usually occurs in long bones.

Case presentation: 38-year-old man diagnosed with SHML based on skin lesion biopsy. Six months after diagnosis, he presented with mechanical pain in the right foot, so he attended a new medical appointment. Physical examination and a non-enhanced X-ray were performed, finding a lytic lesion in the medial cuneiform bone, which was later confirmed with computed tomography and nuclear magnetic resonance imaging. The lytic lesion was excised, curetted and filled with calcium phosphate cement HydraSet (Stryker®). Immunohistochemical tests and anatomopathological study were performed on the excised tissue, evidencing positive CD68 and S100 protein staining and negative CD1a protein staining, as well as histiocyte proliferation. One year after surgery, the patient was asymptomatic and performed activities without any restriction.

Conclusions: Even though HSLM is a rare disease, it should be considered in the differential diagnosis of lytic lesions in the bones, especially when there are lesions in other parts of the body.