Section 6 -

• Langerhans cell disease • Mastocytosis mimicking histiocytic and vasculitic disorders • Cutaneous Borreliosis (early acrodermatitis chronica atrophicans) Bernhard Zelger, M.D., M.Sc. Clinical Department of Dermatology & Venereology Medical University Innsbruck Innsbruck, Austria

CASE 6–1 This punch biopsy of a 5 month old female infant comes from a generalized rash with reddish-blue crusted papules. Biopsy site is abdomen. The diagnosis is: Langerhans cell disease Mononuclear xanthogranuloma (Shapiro) Subacute dermatitis Lichen nitidus Lichen planus Case 6-1 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Histopathologic findings of case presented Spongiotic dermatitis with serum, parakeratosis and intraepidermal lymphocytes and epithelioid mononuclear cells Lichenoid dermal infiltrate of epithelioid mononuclear cells, lymphocytes and eosinophils in an edematous background Epithelioid mononuclear cells reveal hypochromatic, gyriform (kidney-shaped, coffee-bean-like) nuclei with ill-defined eosinophilic cytoplasm, i.e. Langerhans cells Langerhans cells are positive for CD1a, S100 protein (and lag-protein), variable reactivity for Ki-M1p (also seen in monocytes & macrophages) is frequently found Ultrastructural studies show typical trilammellar Birbeck granules This case may be histopathologically (and clinically) misinterpreted as Mononuclear variant of xanthogranuloma (Shapiro) Subacute dermatitis, e.g. diaper rash, seborrheic dermatitis, etc Lichen nitidus Diagnosis: Langerhans cell disease References Zelger B, Rapini RP, Burgdorf W, Burg G: Langerhans cell histiocytosis. In Chapter 4: Haematolymphoid Tumours. World Health Organization Classification of Tumours, ed. Kleihues P et al, IARC Press, Lyon, France, 2006. Pathology and Genetics of Skin Tumours, ed. LeBoit PE, Burg G, Weedon D, Sarasin A, pp 217-219. Zelger B, Burgdorf W: The cutaneous „histiocytoses". In Advances in Dermatology, Vol 17, Chapter 4, ed. James WD, Cockerell CJ, Maloney ME, Paller AS, Yancey KB, Mosby Inc., St. Louis, USA 2002, pp 77-114. CASE 6–2 This excision biopsy of a 3 year old male infant comes from a generalized rash with yellow-brown macules and plaques of several cm diameter with some cayenne-pepper-like aspects. The diagnosis is: Langerhans cell disease Mononuclear xanthogranuloma (Shapiro) Cutaneous Dorfman-Rosai disease Churg-Strauss syndrome Mastocytosis Case 6-2 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Histopathologic findings of case presented Diffuse and dense dermal infiltrate of eosinophils, neutrophils and nuclear debris with perivascular accentuation This infiltrate masks mononuclear cells with convoluted, hypochromatic nuclei, some discernable nucleoli, ill-defined cytoplasm and slight granulation (seen at periphery of process) Mononuclear cells are negative for CD1a and S100 protein, positive for Ki-M1p (monocytes & macrophages) Metachromasia of mononuclear cells with Giemsa, toluidine or methylene blue stains, i.e. (mostly degranulated) mast cells This case may be histopathologically (and clinically) misinterpreted as Langerhans cell disease Mononuclear variant of xanthogranuloma (Shapiro) Cutaneous Dorfman-Rosai disease Leukocytoclastic vasculitis in Churg-Strauss syndrome Diagnosis: Mastocytosis mimicking histiocytic and vasculitic disorders References Dunst KM, Huemer GM, Zelger BG, Zelger B. A new variant of mastocytosis: report of three cases clinicopathologically mimicking histiocytic and vasculitic disorders. Br J Dermatol 2005; 153:642-6 Golkar L, Bernhard JD. Mastocytosis. Lancet 1997; 349:1379-85. Valent P, Horny HP, Escribano L, et al. Diagnostic criteria and classification of mastocytosis: a consensus proposal. Leuk Res 2001; 25 :603-25. CASE 6–3 (1 H&E and 1 immunohistochemical slide plus cartography) This punch biopsy of a 35 year old male comes from several, partially annular macules on the right lower leg. No effect of local antimycotic therapy. Note microorganisms whose exact localization is indicated by cartography; please use your focus at a magnification of 200-400x. The diagnosis is: Dermatophytosis Late stage of erythema chronicum migrans Early lesion of acrodermatitis chronica atrophicans Early stage of lichen sclerosus et atrophicans Secondary syphilis Case 6-3 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Case 6-3 - Slide 2 Click to view with ImageScope Click to view with a Web-Based Viewer Histopathologic findings of case presented Moderate epidermal hyperplasia with parakeratosis including some serum Lichenoid infiltrate of lymphocytes, macrophages and fibroblasts Wiry bundles of collagen in papillary dermis Single spirochetes (B. Burgdorferi) at the periphery of the infiltrate seen in immunostain; exact localization indicated by proferred cartography. This case may be histopathologically misinterpreted as a wide variety of inflammatory disorders including chronic dermatitis ("eczema") or unspecific findings. The clue to correct diagnosis is to think of borreliosis in case of fibrosing dermatitis with lymphocytes, macrophages, fibroblasts and wiry bundles of collagen. Plasma cells may or may not be present. The combination of immunohistochemical staining with focus floating microscopy helps to detect the tiny microorganisms. This technique simultaneously scans through the sections in 2 planes: horizontally in serpentines as in routine cytology, and vertically by focusing through the thickness of the cut (usually 3-4m) at a 200 to 400 fold magnification. Borrelia can be detected as colonies, clusters, paired, or single spirochetes. Borrelia pass through the section plane at various angles, so their form varies from very long and undulated (length 10-30m) to comma-like and dot (diameter 0.2m). They are intimately related to collagen bundles (2m thick) and become swollen and granular as they degenerate. Diagnosis: Cutaneous Borreliosis (early acrodermatitis chronica atrophicans) References Grabner T, Eisendle K, Zelger B. Focus-floating microscopy, gold standard for cutaneous borreliosis? Submitted for publication.