Rosai-Dorfman disease presenting as a solitary soft-tissue mass in the thigh: a case report

Abstract

A 46-year-old man presented to the Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital in February 2004 with a 3-month history of self-detected left thigh mass. It was of spontaneous onset with no history of trauma, associated pain, weakness, or numbness. The patient had full range of movement and no lymphadenopathy was noted. Magnetic resonance imaging (MRI) [ Fig 1] revealed a large area of infiltrative soft-tissue Hong Kong Med J 2019;25:149-51 https://doi.org/10.12809/hkmj164921 thickening at the medial aspect of the left distal thigh and involved the subcutaneous layer. The lesion measured 8.4 × 3.4 × 11.2 cm (anteroposterior × transverse × longitudinal) and was characterised by T1-weighted (T1W) hypointense to isointense and T2-weighted (T2W) fat-suppressed hyperintense signals with internal heterogeneity. Internal foci of hypointensity in the T2W fat-suppressed images were noted. An internal reticular pattern of septal thickening was also found. There was enhancement after gadolinium contrast administration. The margin of the lesion was well delineated from the underlying vastus medialis and sartorius muscles with no features of muscular invasion or destruction. The knee joint was unremarkable and bone marrow signal was normal. The neurovascular bundle was also intact. Overall features were non-specific for either inflammatory or neoplastic pathology.Microscopic examination of an incisional biopsy over the left vastus medialis with a wedge of skin and subcutaneous tissue revealed infiltrate in the subcutis and to a lesser extent the deep dermis. The infiltrate consisted of lymphocytes and a low number of plasma cells. Immunohistochemical stains showed mainly T-cells and some B-cells. Occasional areas with aggregates of paler histiocytic cells were present and suggested granuloma formation. Stains for acid-fast bacilli and fungus were negative. The paler histiocytic cells were S100-positive and showed lymphophagocytosis (Fig 2). Molecular study by polymerase chain reaction showed no clonal T-cell proliferation. The overall features were suggestive of Rosai-Dorfman disease (RDD).Radical excision of the lesion was performed subsequently and included the epimysium of the gracilis, sartorius and aponeurosis of the vastus medialis. The excision margin in the radial excision of the lesion was 2 cm. Microscopic examination revealed that the mass in the subcutis was composed of nodules or aggregates of lymphohistiocytic cells separated by areas of fibrosis. The cellular aggregates were composed of dark areas with plasma cells and lymphocytes and pale areas with CASE REPORT FIG 1. (a) Axial T1-weighted magnetic resonance (MR) image showing a large area of infiltrative soft tissue thickening involving the subcutaneous layer at the medial aspect of the thigh with hypo-to iso-intense signals (arrow). (b) Axial T2-weighted fat-suppressed MR image showing hyperintense signals with internal heterogeneity and foci of hypointensities. Internal reticular pattern of septal thickening was pre...

Extensive Multiorgan and Neurological Involvement on F-18 FDG PET-CT in a Case of Rosai-Dorfman Disease

“…8 The clinical course of RDD is unpredictable, marked by episodes of exacerbation and remission. 9 Molecular studies in RDD showed recurrent mutations involving KRAS and MAP2K1 in one-third cases and this was highlighted in a retrospective study by Garces et al in 2017. 10 Genomic analysis was not performed in our case; however, literature suggests these mutations could explain the extensive disease presentation.…”

Rosai-Dorfman Disease of Bone and Soft Tissue

“…6,19 Some studies report a rapid evolution of the lesions. [36][37][38] Pain may occur in 16.8% of cases. 18 Rosai-Dorfman disease of soft tissue tends to arise in older age than classic nodal disease, with a mean age of 42.5 to 46 years, and demonstrates female predilection.…”

“…Heterogeneous postcontrast enhancement is seen. 30,35,37,38 The lesions are hypermetabolic on positron emission tomography-computed tomography, which facilitates their detection. 30,41…”