This video provides a comprehensive dermatopathology review of cutaneous vasculitis, a broad and complex group of conditions affecting blood vessels in the skin. Jared Gardner and Eddie Fulton delve into the microscopic identification of various vasculitis types, beginning with leukocytoclastic vasculitis (LCV), characterized by neutrophil-mediated vessel damage, fibrinoid necrosis, and nuclear debris. They highlight the diagnostic significance of biopsy depth for systemic involvement, contrasting superficial LCV with deeper forms and the role of direct immunofluorescence in conditions like Henoch-Schonlein Purpura. The discussion extends to severe presentations such as bullous LCV with epidermal ischemia, optimal biopsy techniques including the "double punch," and distinct patterns associated with specific conditions. These include levamisole-associated vasculitis (linked to drug use, presenting with purpura and thrombi), cryoglobulinemia (featuring glassy cryoglobulin deposits), polyarteritis nodosa (involving deep medium-sized muscular vessels), eosinophilic vasculitis (suggesting drug reactions or Churg-Strauss Syndrome), and fibrosing vasculitis as seen in granuloma faciale and erythema elevatum diutinum. The presentation consistently emphasizes the critical need for correlating microscopic findings with clinical history for accurate diagnosis and management.
Exploring Cutaneous Vasculitis: A Dermatopathology Review
0:00 Introduction to Cutaneous Vasculitis: The video introduces vasculitis in the skin as a complex and broad topic, requiring differentiation between localized and systemic forms, and recommends Andrew Carlson's 2010 paper for classification.
1:03 Defining Leukocytoclastic Vasculitis (LCV): LCV is a common neutrophilic vasculitis where vessel damage is mediated by neutrophils. It often affects the skin but may indicate systemic involvement, warranting clinical notification.
Low power: Look for clusters of neutrophils and significant hemorrhage in the dermis.
High power: Confirm neutrophils around vessels, evidence of leukocytoclasis (nuclear debris from breaking down neutrophils), and fibrinoid necrosis (fibrin deposition) in the vessel walls.
Key takeaway: The presence of fibrin and nuclear debris is crucial for diagnosing LCV, distinguishing it from other neutrophilic infiltrates.
5:17 Superficial vs. Deep Involvement & Immunofluorescence:
Superficial LCV: Inflammation primarily in the superficial dermis, typically skin-confined.
Deep LCV: Involvement of deeper dermal vessels raises the possibility of systemic vasculitis.
Henoch-Schonlein Purpura (HSP): An IgA-mediated systemic vasculitis (common in children) that looks similar to LCV on H&E and requires direct immunofluorescence (DIF) to detect IgA deposits.
7:57 Bullous LCV and Ischemia: Extensive vascular damage, especially with deeper involvement, can lead to ischemia, causing epidermal death and detachment, clinically manifesting as blisters (bullous LCV).
Incisional biopsy: Recommended for adequate depth (deep dermis to subcutis).
"Double punch": A practical method for obtaining deeper tissue when an incisional biopsy is not feasible.
14:45 Recognizing Ischemic Epidermis: Appears pale, "washed-out," or "ghost-like" due to lack of blood flow; nuclei may dissolve, but keratin filaments (pink cytoplasm) persist.
15:46 Fibrin Thrombi: Fibrin clots forming within damaged vessel lumens further occlude blood flow and contribute to ischemia, a feature sometimes seen in LCV.
20:29 Levamisole-Associated Vasculitis: Presents with purpura on the ears or nose, bullous changes, significant fibrin thrombi, and subtle LCV. It is associated with levamisole (a cocaine cutting agent) and often requires clinical history and drug screening for diagnosis.
22:39 Cryoglobulinemia: Characterized by bright pink, glassy, or hyaline cryoglobulin deposits filling vessel lumens, often with concomitant LCV. Mixed types (2 & 3) involve both cryoglobulins and neutrophilic vasculitis. DIF (IgM/IgG staining) and PAS stain help confirm.
29:48 Polyarteritis Nodosa (PAN): A vasculitis of medium-sized muscular vessels, typically found deep in the dermis or subcutis, presenting as painful, tender nodules. Microscopic findings include neutrophilic destruction of the vessel wall and a lumen packed with fibrin. Systemic involvement is common.
34:44 Eosinophilic Vasculitis: When vasculitis is accompanied by numerous eosinophils, consider drug-associated causes or Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis - EGPA). Careful microscopic differentiation of eosinophils from neutrophils is important.
36:58 Granuloma Faciale (GF): Appears as a violaceous plaque on the face. Histologically, it features a "gren zone" (normal dermis above inflammation) and a dense mixed inflammatory infiltrate (eosinophils, histiocytes, neutrophils, plasma cells) but typically no true granulomas.
40:41 Fibrosing Vasculitis in GF and Erythema Elevatum Diutinum (EED):
Both conditions can show a sclerosing or fibrosing vasculitis with an "onion skin" pattern of collagen and spindle cells wrapping around vessels.
EED: A rare condition presenting as firm nodules on extremities (hands, feet, elbows), characterized by extensive sclerosis and fibrosis trapping small vessels, along with subtle LCV and eosinophils.
46:20 Conclusion: The video concludes by reiterating the complexity of vasculitis and emphasizing the importance of recognizing specific microscopic patterns in conjunction with clinical context for accurate diagnosis and patient management.