Abstract
Sneddon syndrome (SS) is a rare disorder that has a variety of pathologic associations, often described as the first cutaneous manifestation of Antiphospholipid syndrome. It is characterized clinically by livedo racemosa (LR) and cerebrovascular symptoms (CVS), with the former showing microangiopathic disease in the deep dermal vessels on skin biopsy. Skin findings usually precede the development of CVS, and rely on appropriate sampling of the central area of the rash since that is where the occluded artery is located. We discuss a case of a 55-year-old female with a remote history of stroke who presented with a new violaceous and painful net-like discoloration on her thigh. Multiple punch biopsies from only the peripheral livid area of the rash were performed. The differential included vasculitis, infection, or medication-related etiologies. Skin biopsy revealed full thickness epidermal necrosis, necrosis of hair follicles and eccrine glands, and rare intravascular fibrin thrombi in the superficial dermal vessels. CBC and coagulation tests were normal. Serology tests including workup for infectious (e.g., syphilis, HIV, HBV, HCV), autoimmune (e.g., lupus anticoagulant, anti-?2-microglobulin, anti-cardiolipin, cryoglobulin, complement, ANCA, anti-DsDNA, anti-Smith, ANA, and rheumatoid factor), and coagulopathic (e.g., antithrombin III, protein S, protein C) etiologies were all negative. Although the range of biopsy findings had not been previously described in SS, the histology, in addition to the clinical picture of stroke and LR, were consistent with this diagnosis. Our case highlights the importance of familiarity with the range of biopsy findings that can be seen in SS, particularly in the setting of suboptimal sampling. It is one of the few reports where the rash occurred long after cerebrovascular disease, and where the dermatopathologists recognition of the combination of clinical and microscopic findings led to this rare diagnosis.
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