In addition, the patient also complained of vague bilateral lower extremity pain of several months duration. Magnetic resonance imaging (MRI) of the lower extremities was performed for investigation of the patients leg pain, which showed diffuse replacement of the fatty marrow of the long bones with abnormally diminished T1 signaling, suggestive of an infiltrative process of the bone marrow such as storage disorder, leukemoid or histiocytic infiltration. Keywords:dermatology, granuloma, immunohistochemistry, pathology dermatopathology == Case statement == A 35-year-old White male presented with a 5-month history of a brown/red occasionally pruritic, non-painful skin rash. The rash was initially confined to the central trunk but subsequently involved the upper extremities and neck. In addition, the patient also complained of vague bilateral lower extremity pain of several months duration. Magnetic resonance imaging (MRI) of the lower extremities was performed for investigation of the patients leg pain, which showed diffuse replacement of the fatty marrow of the long bones with abnormally diminished T1 signaling, suggestive of an infiltrative process of the bone marrow such as storage disorder, leukemoid or histiocytic infiltration. A bone marrow biopsy was performed, which showed Rabbit polyclonal to EGFLAM variable cellularity estimated at 3050% with trilineage hematopoiesis, stainable iron, no granuloma and no evidence of a leukemic disorder. AL 8697 In addition, no lymphoid aggregates were noted. A skin biopsy from your mid-abdominal region performed showed skin with superficial and deep xanthogranulomatous infiltrate, including multinucleate Touton-like giant cells in keeping with the radiologic findings suggesting a histiocytic infiltration. The patient was referred to the Genetic Medical center at Brigham and Womens Hospital for investigation of a possible storage disorder. However, the acutely progressive tempo of his clinical course, essentially normal biochemical screening [in particular, the alkaline phosphatase, liver function assessments and complete blood count (CBC)] and the absence of organomegaly were considered to be inconsistent with a storage disease (Fabry or Gauchers disease). A 99mTc-Methyl disphosphonate (TC-MDP) bone scan of the entire body was performed, which showed bilateral symmetric uptake in the frontal skull, distal femurs, tibiae and ankles, as well as the clavicular heads (Fig. 1). The patient was referred to Dermatology for further evaluation and management. == Fig. 1. == TC-MDP bone scan revealing characteristic bilateral symmetric uptake in AL 8697 the frontal skull, distal femurs, tibiae and ankles, as well as clavicular heads. The patients past medical history was significant for obesity, sleep apnea, alcoholism and panic attacks. There was no significant family history. On physical examination, the patient was found to have diffuse brown AL 8697 maculopapular skin lesions around the trunk and extremities (Fig. 2A). Bilateral scleral and conjunctival brown infiltrates were noted (Fig. 2B), in addition to bony tenderness of both ankles and knees. == Fig. 2. == A) Photograph of the cutaneous eruption showing browney macular and indurated papular eruption in chest, upper stomach and upper extremities. B) Photograph of the eye exposing scleral and conjunctival brown infiltrates. Laboratory studies revealed an elevated C-reactive protein (CRP;>17.80), erythrocyte sedimentation rate (ESR; 25) and hypoalbuminemia (2.7 g/dl). CBC, urea and electrolytes, lipids, urinary studies, liver function and antinuclear antibodies were all within normal limits. A skin biopsy of one of the maculopapular lesions was performed (Figs. 3and4). The 5-mm punch biopsy of the mid-back showed a dense superficial and deep dermal xanthogranulomatous infiltrate composed of histiocytes with abundant xanthomatous cytoplasm, multinucleate Touton-like giant cells and prominent intervening fibrosis. Immunohistochemistry showed the following staining profile in lesional cells: CD163 strongly positive, CD68 weakly positive and focal positivity for S-100 only in the most superficial component. HMB-45, CD1a and langerin were all unfavorable. == Fig. 3. == A) Low-power magnification showing skin with dense superficial and deep xanthogranulomatous infiltrate and associated intervening fibrosis (H&E, initial magnifications: 2). B) Medium-power magnification showing dense superficial xanthogranulomatous infiltrate, including multinucleate Touton-like giant cells (H&E, initial magnifications: 20). C) Multinucleate Touton-like giant cells and associated intervening fibrosis (H&E, initial magnifications: 60). == Fig. 4. == A) CD163 immunohistochemistry at 20 magnification. B) CD68 immunohistochemistry at 20 magnification. C) S-100 immunohistochemistry at 20 magnification. The subacute clinical course, lack of evidence for an inborn error of metabolism, including a normal bone marrow biopsy, the radiological findings, as well as the morphological appearance on routine H&E (hematoxylin and eosin) staining and the immunohistochemical profile led to a diagnosis of ErdheimChester disease (ECD) as the cause of the patients symptoms. The patient received interferon therapy and is currently stable with.