Ultrastructural aspects of primary anetoderma.

Anetoderma is a rare cutaneous disorder characterized by focal loss of dermal elastic tissue due to unknown mechanisms. Primary anetoderma develops on clinical normal skin, without any preceding dermatosis and it can be associated with autoimmune conditions. Secondary anetoderma develops on the same area of a previous disorder, such as infectious, neoplastic or inflammatory diseases. A 37-year-old female patient noticed for 4 years circumscribed, normochromic, asymptomatic herniated plaques on the trunk and upper limbs. Family history was negative. Only a positive antinuclear factor (ANF) test, with titer of 1:160 and nuclear homogeneous pattern was found. Light microscopy with Weigert staining showed a lessening of elastic fibers with fragmentation; the oxytalanic fibers were also affected or absent. Transmission electron microscopy showed fragmentation and granular degeneration of elastic fibers. With greater magnification, fragments similar to those seen with optical microscopy were identified. The collagen fibers did not present any alteration. The examination of the dermis with scanning electron microscopy also identified fragmentation and significant fissures of the elastic tissue, granular degeneration was also observed. With greater magnification fragmented elastic fibers were seen.

Light and electron microscopy of eruptive collagenoma.

Connective tissue nevi may be multiple or solitary, sporadic or familial. Eruptive collagenoma is a variant of the acquired collagenomas characterized by multiple sclerotic papules with an acute onset. A 13-year-old girl reported that in the past year, small asymptomatic lesions began to appear in her skin, 30 lesions were seen in the trunk, 5 in the cervical region and 1 in the face. Light microscopy with hematoxylin and eosin staining showed sparse collagen fibers, with Weigert staining diminished elastic tissue was observed. Scanning electron microscopy of the dermis showed individualized collagen fibers forming waved compact masses and not bundles. Transmission electron microscopy also showed sparse and loose collagen fibers with different diameters in cross sections.