Lichen planopilaris and pseudopelade of Brocq involve distinct disease associated gene expression patterns by microarray.

BACKGROUND: Lichen planopilaris (LPP) and pseudopelade of Brocq (PPB) are two scarring alopecia diagnoses that exhibit similar clinical features. Some suggest LPP and PPB are not distinct diseases, but rather different clinical presentations in a spectrum derived from the same underlying pathogenic mechanism. OBJECTIVE: We explored the degree of similarity between LPP and PPB gene expression patterns and the potential for common and unique gene pathway and gene activity in LPP and PPB using microarrays. METHODS: Microarray analysis, using a 21K cDNA set, was performed on pairs of biopsies obtained from affected and unaffected scalp of untreated patients. Diagnosis was confirmed by histopathology. Significantly differentially expressed genes were identified by analysis of microarray results in various datasets and screened for signaling pathway involvement. Selected genes were validated by quantitative PCR and immunohistology. RESULTS: The global gene expression profiles in LPP and PPB versus comparative intra-control scalp tissue were distinguishable by significance analysis of microarrays (SAM). There was limited commonality in the gene expression profiles between LPP and PPB. Specific genes, such as MMP11, TNFSF13B, and APOL2, were identified with significantly differential expression in association with LPP versus PPB. CONCLUSIONS: Our findings may have important implications for understanding the pathogenesis of LPP and PPB at the molecular level. Results suggest LPP and PPB involve different mechanisms of disease development and should be regarded as biologically distinct cicatricial alopecia diagnoses. Genes that we have identified may be useful as markers of the respective diagnoses and may be potential therapeutic targets.

Histologic spectrum of melanocytic nevi removed from patients > 60 years of age.

BACKGROUND: The histology of melanocytic nevi removed from older patients often differs from that of nevi from younger adults. According to the literature, the most common nevus in older individuals is the intradermal nevus, and purely junctional nevi are rare and should alert the pathologist to a possible melanoma precursor. OBJECTIVE: To evaluate the histologic features of melanocytic nevi removed from patients > 60 year of age. METHODS: Biopsies of nevi (N=215) from 172 patients > 60 years (mean age 69+/-7 years) were examined retrospectively by three dermatopathologists, a consensus diagnosis was rendered, and the spectrum of histologic features was documented. RESULTS: Junctional melanocytic nevi were frequently diagnosed in older patients (21% of cases) and a lentiginous, often heavily pigmented growth pattern was common (12% of nevi). Severely atypical (dysplastic) changes were found in 6% of nevi removed from older patients. CONCLUSIONS: We conclude that benign junctional nevi are relatively common in older patients and that a lentiginous, heavily pigmented growth pattern, traditionally associated with younger individuals, is often seen in both junctional and compound nevi in this older age group. This pattern must be differentiated from dysplastic nevus and melanoma in situ, which they may clinically resemble.

Spectroscopic assessment of dermal melanin using blue vitiligo as an in vivo model.

BACKGROUND: Spectroscopic methods have been used to analyze in vivo melanin in the past but the specific effect of melanin depth on autofluorescence and reflectance spectroscopy has not been determined. In patients with blue vitiligo, three distinctive clinicopathologic patterns are present: (1) normal skin with normal epidermal melanin pigmentation (2), skin of blue vitiligo with dermal melanin pigmentation, and (3) tissue of regular vitiligo with no melanin pigmentation. Blue vitiligo may thus serve as an in vivo model to assess dermal pigment using spectroscopic techniques. OBJECTIVES: To evaluate the reflectance and autofluorescence spectra of a patient with blue vitiligo in order to assess the effect of melanin pigmentation and its localization on the optical properties of the skin. METHODS: The blue-gray, normal and depigmented lesions of a patient with blue vitiligo were analyzed using reflectance and fluorescent spectroscopy. The condition was likely induced by a phototoxic reaction in a patient with pre-existing vitiligo. These data were then correlated to the histologic and electron microscopic findings present in the various types of lesions. RESULTS: Reflectance spectroscopy detected little difference in spectral shape between skin sites affected by blue vitiligo vs. vitiligo. Autofluorescence spectroscopy detected an apparent difference between the two types of lesions, with the blue-gray lesions (blue vitiligo) showing lower fluorescence intensity and spectral maximum position red-shifted compared with regular vitiligo, whereas regular vitiligo showed more intense hemoglobin absorption than the blue vitiligo. CONCLUSIONS: Dermal melanin present in blue vitiligo can be well characterized by autofluorescence spectroscopy, while little difference in reflectance spectral shape exists between vitiligo and blue vitiligo. Thus, autofluorescence spectroscopy may better identify deeper structures in skin tissue, such as melanin, than reflectance spectroscopy.

Actinic granuloma is a unique and distinct entity: a comparative study with granuloma annulare.

Since the initial description of actinic granuloma (AG), debate has continued over whether it should be considered a specific condition or simply granuloma annulare (GA) located in sun-exposed areas of skin. We conducted a case-control study to clarify this issue. Twenty cases given the diagnosis of AG between 1991 and 2001 were retrieved from our archives. We applied the following inclusion criteria: extensive loss of elastic tissue in or at the side of the granuloma, and elastophagocytosis. Sixteen cases of GA that involved sun-exposed and non-sun-exposed sites, 8 cases from each group, were randomly selected as controls. Histologic parameters were quantitated on hematoxylin-eosin, Verhoeff van Gieson, and Alcian blue stains for each case. Results were statistically analyzed by SPSS program version 9. Fourteen cases of AG met our inclusion criteria. Presence of mucin, occurrence of multinucleated giant cells, and the type of granulomata were of high statistical significance (p < 0.01) in distinguishing the two entities. We also found that the location of the granulomata in these conditions is different and of statistical significance (p < 0.05). Based on histomorphology, we believe that AG should be considered a separate, independent condition and should be distinguished from GA even in sun-exposed areas of skin.