Rosai-Dorfman disease (RDD) is a rare, benign histiocytic proliferative disorder primarily occurring in the lymph nodes. Extranodal disease can occur in skin and soft tissue, central nervous system, gastrointestinal tract, and breast. Here we present a case of a 55-year-old female with a history of hypertension, hyperlipidemia, and diabetes mellitus who presented with a fixed solid mass localized to the right medial thigh. Excision revealed S100 and CD 68 positive scattered lymphoid aggregates and emperipolesis, hallmark molecular and cytopathologic features of RDD. RDD is a nonmalignant, classically sporadic histiocytosis. Clinical outcome in terms of mortality seems to be favorable in most cases, however given the benign and slowly progressive nature of the disease, conservative management with observation is typical, with surgical excision recommended for larger lesions. Currently, therapy revolves around surgical and immunosuppressive treatments, but the optimal diagnostic and therapeutic management of RDD remains to be defined.

Heparin-induced thrombocytopenia (HIT) is characterized by low platelets and thrombosis after exposure to Heparin products. It is classically characterized by a rapid and significant drop in platelets and life-threatening thrombosis. Thrombosis can occur up to 50% of the cases if left untreated. It requires immediate discontinuation of all heparin products and switching to a non-heparin anticoagulant to prevent further thrombosis. Here we present a case of a 56-year-old male who presented to the Emergency Department with sudden onset of severe left leg pain. Duplex study showed arterial thrombosis in the common iliac and distal iliac arteries. He received TPA at once and underwent thrombectomy while his platelet continued to drop. He used Low Molecular Weight Heparin (enoxaparin) for bridging after his tonsil surgery a week prior to this hospital admission. His HIT assay was found to be positive and despite the Argatroban therapy his clinical condition continued to worsen while his platelet count continued to drop. Given the refractory nature of the thrombosis and thrombocytopenia; Intravenous immunoglobulin (IVIG) therapy was introduced. The patient showed a great response and his platelet count improved to 150,000/ μ . He was discharged on warfarin with a closer follow-up. Few case reports have described the treatment of such refractory cases using intravenous immunoglobulin (IVIG), resulting in stabilized platelet counts, reduced platelet activation, and reduced thrombotic complications, the exact mechanism of which is unknown. It is thought that IVIG inhibits platelet activation by binding as platelet receptors, which would otherwise bind with heparin–platelet factor 4 complexes and HIT antibodies.

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