Cutaneous marginal zone B-cell lymphoma evolving into anetoderma: a role of matrix metalloproteinases?

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.

A Clinicoimmunohistopathologic Study of Anetoderma: Is Protruding Type More Advanced in Stage Than Indented Type?

Background. The clinical and histopathologic classification of anetoderma are not well characterized. Objective. We aimed to investigate the clinical and histopathologic characteristics of anetoderma and to correlate clinical phenotypes with immunohistopathologic findings. Methods. We retrospectively reviewed the medical records of 30 patients with anetoderma and performed immunohistochemistry for elastin, fibrillin-1, metalloproteinase- (MMP-) 2, MMP-7, MMP-9, and MMP-12, and tissue inhibitor of metalloproteinase- (TIMP-) 1 and TIMP-2. Results. Protruding type (n = 17) had a longer disease duration and more severe loss of elastin, without changes in fibrillin, than indented type (n = 13). MMP-2 and MMP-9 showed significantly higher expressions in the dermis compared with controls (p < 0.05). MMP-7 and MMP-12 showed little expressions in both anetoderma and control tissue. TIMP-1 was highly expressed in anetoderma lesions and controls. TIMP-2 expression was variable. Conclusions. Our findings suggest that protruding type anetoderma may represent a more advanced stage and that MMP-2 and MMP-9 could be responsible for elastic fiber degradation in anetoderma.