Traumatic neuroma of the lower lip with intraepithelial nerve fibers.

A 42-year-old man had noticed a small tender papule on his lower lip, and the papule clinically became unnoticeable after cryosurgery. He visited our clinic because the lesion recurred up to the original size after 9 months. On examination, a linear scar and a papule, 4 mm in diameter, were observed on the mucosal lower lip. The papule was resected and histopathologically showed proliferation of nerve fibers in irregular and tortuous fascicles, thus establishing the diagnosis of traumatic neuroma. Immunohistochemical staining by antineuron-specific enolase (NSE) antibody showed proliferation of axons in the upper lamina propria and even in the mucosal epithelium overlying the tumor. Traumatic neuroma of the lower lip is very rare, and a literature search showed only one reported case. Intraepithelial proliferation of axons may be one of the characteristics of mucosal traumatic neuroma.

The interaction of inflammatory cells in granuloma faciale.

Granuloma faciale (GF) is a rare chronic inflammatory skin disease characterized by single or multiple reddish-brown cutaneous plaques or nodules. Although this condition is benign, its clinical course is extremely chronic with poor response to therapy. The typical histopathological features of GF include vasculitis with mixed cellular infiltration; however, its etiopathogenesis remains unknown. Here, we describe the case of a 76-year-old man with GF resistant to topical steroids. Biopsy of the lesion revealed i) dense mixed inflammatory cellular infiltrates of lymphocytes, histiocytes, neutrophils, and eosinophils, ii) mild perivascular nuclear dust and swollen endothelium of blood vessels, and iii) a narrow Grenz zone beneath the epidermis. Immunohistochemical staining demonstrated mixed cellular infiltrates intermixed with CD1a(+) dendritic cells, CD68(+) histiocytes, and CD4(+) and CD8(+) T cells.

COL7A1 mutation G2037E causes epidermal retention of type VII collagen.

COL7A1 glycine substitution (GS) mutations result in dominant and recessive dystrophic epidermolysis bullosa (DDEB and RDEB). Here, we report a DDEB family in which retention of type VII collagen by epidermal keratinocytes was observed for a female proband. Mutational analysis detected a GS mutation, G2037E, in the proband and her affected father. To demonstrate direct association of G2037E and type VII collagen retention we introduced this mutated COL7A1 gene into cultured keratinocytes using retroviral methods. This mutation was dominant, so we transferred a 1:1 mixture of wild-type (unaffected) and G2037E-mutated COL7A1, together, in addition to the unaffected gene or the mutated gene alone. The increase in type VII collagen cytoplasmic staining in the G2037E/wild transfectant cell samples was compared with that for control/wild-type cells. Intracellular collagen VII staining in the G2037E (alone)-transfected cells was even stronger than for the G2037E/wild transfection sample. These results indicate that the G2037E COL7A1 mutation leads to increased epidermal retention of type VII collagen in vivo, and also suggests that homozygotes carrying this dominant GS mutation may have more severe phenotypes than heterozygotes. This study furthers our understanding of GS COL7A1 mutations in DEB.