LAUSR

A man in his thirties, presented for evaluation due to painful ulcers involving both lower extremities. He complained of weight loss, fatigue, blurred vision and epistaxis. On physical examination, multiple ulcers with a fibrinous base and purpuric circinate edges were observed on both legs (Fig. 1). Laboratory findings showed normocytic–normochromic anaemia, thrombocytosis 921 9 10/L (normal 130–400 9 10/L), low complement levels, a monoclonal serum component (IgM-lambda) of 17.25 g/L and positive type I cryoglobulins. Histopathologic examination revealed small vessels containing an eosinophilic periodic acid Schiff-positive hyaline material, throughout the dermis (Fig. 2a). Direct immunofluorescence (Fig. 2b) showed the deposition of IgM on the wall and within small vessels throughout the dermis, both findings being compatible with type I cryoglobulinemia. Bone marrow biopsy revealed an IgM-lambda lymphoplasmacytic lymphoma (Waldenstr€ om macroglobulinemia). Presuming a spurious elevation of platelet counts due to cryoglobulin precipitates, a complete blood count (CBC) analysis was performed after an incubation period of 30 min at 37°C, revealing a normal platelet count (153 9 10/L). The patient was diagnosed with a lymphoplasmacytic lymphoma negative for the MYD-88 gene mutation, an associated type I cryoglobulinemia and pseudothrombocytosis because, particularly in high cryoglobulin titre states, cryoprecipitates can produce structures on peripheral blood smears that may be mistaken for platelets by automated cell differential analysers. He received treatment with dexamethasone, rituximab and cyclophosphamide for the lymphoma and plasmatic exchanges with albumin and immunoglobulin infusions to treat the hyperviscosity symptoms. He responded well to these treatments without side effects. The leg ulcers resolved with the combination of systemic and local treatment. Cryoglobulins are immunoglobulins that precipitate in vitro at temperatures less than 37°C and redissolve on warming. Type I cryoglobulinemia consists of a monoclonal immunoglobulin, generally IgM or IgG. It is usually associated with a B-cell proliferative disorder that may be indolent, smouldering or malignant. It can cause serum viscosity from elevated levels of paraproteins in the blood vessels, resulting in precipitation in the microcirculation and vascular occlusion. Dermatologic manifestations usually develop as purpuric macules or papules on the lower extremities, acrocyanosis, livedo reticularis, Raynaud phenomenon, skin ulcers and necrosis. On skin biopsy, a noninflammatory thrombotic occlusion of dermal vessels by eosinophilic periodic acid Schiff-positive hyaline material