Morphea limited to the superficial reticular dermis: An underrecognized histologic phenomenon

Morphea (localized scleroderma) is a disease of unknown etiology, presentin g as circumscribed areas of indurated skin. Histologically, most cases of m orphea feature thickened collagen bundles in the deep reticular dermis, som etimes also extending into the superficial dermis or into the subcutis. We present six cases of morphea in which typical histologic features were rest ricted to the superficial dermis and contrast these with 27 additional biop sies of conventional morphea seen during the same time period. Sections wer e stained for elastic fibers, and dermal dendritic cells were labeled with antibodies to CD34 and Factor XIIIa. All six cases showed thickened collage n bundles restricted to the superficial dermis, spacing the deep dermis and without associated evidence of lichen sclerosus et atrophicus (LSA). Derma l elastic fibers were not appreciably decreased in number. There was loss o f CD34-positive dermal spindle cells in each of our six superficial example s of morphea, which was restricted to the area of altered collagen in four of the six cases. This report highlights the distinctly uncommon phenomenon of morphea presenting solely as alteration of the superficial reticular de rmis, without features of LSA. The selective loss of CD34-labeled spindle c ells may provide information regarding the role of these putative immune ac cessory cells in morphea. Recognition of this manifestation of morphea may be helpful diagnostically.