—  SHORT COURSE  —

INFLAMMATORY DISORDERS OF THE SKIN AND SUBCUTIS:
A PRACTICAL AND ANALYTICAL APPROACH



CASE #6: CELL POOR INTERFACE DERMATITIS OF
COLLAGEN VASCULAR DISEASE (Tables 2,3,4)

Cynthia M. Magro, M.D., A.Neil Crowson, M.D., and Martin C. Mihm Jr., M.D.




The two main connective tissue disease syndromes which are characterized by a cell-poor vacuolar interface dermatitis are systemic lupus erythematosus and dermatomyositis. In acute systemic lupus erythematosus the changes are subtle: the epidermis and the stratum corneum may not show any appreciable alterations save a focal and often subtle basilar vacuolopathy with a few lymphocytes tagging along the dermal-epidermal junction. What is more striking are alterations of the dermis comprising splaying of the collagen fibres by mucin, with superficial vascular plexus ectasia. Critical to the diagnosis is the presence of clinical signs and symptoms which fulfill the American Rheumatology Association criteria for systemic lupus erythematosus (see Table 2). The differential diagnosis of this particular reaction pattern includes dermatomyositis which will be considered presently. We have also observed exactly this morphology in patients with constitutional symptoms simulating systemic lupus erythematosus in the setting of parvovirus B19 infection and Lyme disease. We recommend that any patient who presents with an acute symptom complex characterized by a skin rash with arthralgia and constitutional symptoms, and a skin biopsy histomorphologically resembling acute systemic lupus erythematosus as defined by the criteria above, be evaluated for parvovirus B19 infection and Lyme disease, the latter particularly if the patient is from an endemic area.


Interface Dermatitis Of Collagen Vascular Disease - Systemic Lupus Erythematosus

Dermatomyositis can have many of the aforementioned prototypic histological features, that is, a cell-poor interface dermatitis with pan-dermal mucinosis and vascular ectasia (see Table 4). However, a humoral-based microangiopathy with C5b-9 as the effector mechanism is integral to the pathogenesis of the cutaneous lesions of dermatomyositis; in consequence an active microangiopathy characterized by endothelial cell necrosis and denudement with zones of reduced vascular density of the superficial plexus is present. Similar vasculopathic changes are seen in anti-Ro- associated systemic lupus erythematosus. Patients with anti-Ro-associated systemic lupus erythematosus often have a cell-rich interface injury pattern i.e. a lichenoid dermatitis. In addition, immunofluorescent testing reveals a positive lupus bant test in concert with C5b-9 deposition along the dermoepidermal junction.

References

  1. Clark WH Jr, Reed RJ, Mihm MC Jr. Lupus erythematosus, histopathology of cutaneous lesions. Hum Pathol. 1973;4:157-163
  2. Crowson AN. Superficial and deep perivascular dermatitis. In : Barnhill R, Crowson AN, Busam K, Granter S ed's. Textbook of Dermatopathology. New York : McGraw-Hill Co, 1998:69-81
  3. Crowson AN, Magro CM. The role of microvascular injury in the pathogenesis of cutaneous lesions of dermatomyositis. Hum Pathol 1996;27:15-19
  4. Crowson AN, Magro CM, Dawood MR. A causal role for parvovirus B19 infection in the pathogenesis of adult dermatomyositis and other autoimmune syndromes. J Cutan Pathol 2000;27:505-15
  5. Jaworsky C. Connective tissue diseases. Elder D, Elenitsas R, Jaworsky C, Johnson B, Ed's. Lever's Histopathology of the skin, 8th Ed'n, Philadelphia: Lippincott-Raven, 1997:253-286
  6. Magro CM, Crowson AN, Harrist TJ. The use of antibody to C5b-9 in the subclassification of lupus erythematosus. Br J Dermatol 1996;134:855-862
  7. Magro CM, Crowson AN, Regauer S. The dermatopathology of mixed connective tissue disease. Am J Dermatopathol 1997;19:205-212
  8. Magro CM, Crowson AN. The immunofluorescence findings in cutaneous lesions of dermatomyositis : a comparative study versus lupus erythematosus. J Cutan Pathol 1997;24:543-552
  9. Magro CM, Crowson AN. The cutaneous pathology asssociated with seropositivity for antibodies to SSA (Ro): a clinicpathologic study of 23 adults patients without subacute lupus erythemnatosus. Am J Dermatopathol 1999;21:129-137
  10. Magro CM, Dawood MR, Crowson AN. The cutaneous manifestations of parvovirus B19 infection. Hum Pathol 2000;31:488-97