Colloidal milio pathology

Introduction

Colloid milium is a rare condition characterized by a dome shape translucent papules and dermal colloid statement. Four variants are recognized: adult, youth, pigmented and nodular colloid milia.

Histology colloid millium

In the papillary dermis, homogeneous eosinophilic masses of a colloid are found (figures 1, 2, 3). The colloid masses are split or cracked, and these fissures can be lined with fibroblasts (figure 4 arrow).

In adult-type colloidal milia, there is often a grenz zone with subepidermal preservation of the papillary dermis (figure 5 arrow) and solar elastosis. There is a saving of attached structures (figure 6).

Special studies for milium colloid.

The staining is positive for PAS. Congo red and crystal violet can also be positive.

Differential diagnosis colloid millium

Primary cutaneous amyloidosis: Differentiation It can be difficult and done only by special stains. Unlike amyloidosis, milium colloid is laminin and type IV negative. collagen. Cytokeratin is positive in lichen amyloidosis and may be useful in differentiating colloidal milia, which stain negatively; however, nodular amyloid and skin involvement systemic amyloids are also negative for cytokeratin. Juvenile-type colloidal milia may stain positively for cytokeratin and are considered by some authors to be a variant of lichen amyloidosis. Electron microscopy of amyloidosis reveals straight, unbranched filaments, while colloid milia filaments are shorter, branched, and wavy.

Erythropoietic protoporphyria: hyaline deposits are observed around and within the surface blood vessel walls The involvement of the dermoepidermal junction (preserved in colloidal milia) can be seen.

Lipoid proteinosis: dermal deposits are accentuated around blood vessels. Atrophy of eccrine Sweat glands and the involvement of pilosebaceous units are additional features. Unlike milium colloid, there is positive staining for laminin, type IV collagen, and cytokeratin.

Woody conjunctivitis: Juvenile colloidal milia have been reported to be associated with this chronic pseudomembranous conjunctivitis. Plasminogen deficiency may be a common causality. Histology of woody conjunctivitis reveals thinned or eroded conjunctiva epitheliumsubepithelial amorphous eosinophilic masses and foci of granulation tissue.