Elastic fiber pattern in regressing melanoma: a histochemical and immunohistochemical study.

BACKGROUND: Although histopathologic identification of regression of melanoma is usually straightforward, sometimes it can be difficult to distinguish it from scarring fibrosis. Therefore, this study investigates the elastic fiber pattern in melanomas associated with either regression or scars. METHODS: We compared 33 invasive melanomas with the fibrosing stage of regression to 10 cases of invasive melanomas with scarring fibrosis. None of the regression cases had a prior surgical procedure. Elastic fiber patterns were evaluated with Verhoeff's elastic van Gieson stain (EVG) and elastin immunostain. RESULTS: Elastin immunostain was superior to EVG in revealing the elastic fiber patterns. Both regression and scars had decreased to absent elastic fibers in the areas of fibrosis. However, areas of regression had a well-defined compressed layer of thin elastic fibers pushed down from the papillary dermis to the base of the fibrosis. In contrast, the base of scars lacked this compressed elastic layer and had instead an abrupt transition to the thick elastic fibers of the spared reticular dermis. CONCLUSIONS: We have identified distinct changes of the elastic tissue network, which more accurately define the presence of regression in melanoma and distinguish it from scarring fibrosis.

The use of elastin immunostain improves the evaluation of melanomas associated with nevi.

BACKGROUND: Twenty to 30% of malignant melanomas are associated with melanocytic nevi; however, sometimes it is difficult to distinguish the melanoma from the nevus by routine histology. We have previously described distinctive patterns of elastic fibers in nevi and in melanomas. METHODS: We analyzed elastic fiber patterns using elastin immunostain and elastic van Gieson (EVG) stain in 30 cases of invasive melanomas associated with nevi, 12 control melanocytic nevi and 14 control invasive melanomas. RESULTS: Elastin immunostain was superior to EVG in showing the elastic fiber patterns. In nevi, the elastic fibers were preserved between nests and often around individual melanocytes. In contrast, melanomas had markedly decreased elastic fibers in the stroma and within the nests of melanocytes. The melanoma pushed down the pre-existing thin elastic fibers of the papillary dermis, forming a compressed layer at its base, which separated the melanoma from the nevus. On sun-damaged skin, the solar elastosis had similar elastin and EVG patterns. In three cases with dense inflammation, the layer of elastic fibers between melanoma and nevus was still present but less evident. CONCLUSIONS: The distinctive patterns of elastic fibers, best shown by the elastin immunostain, were helpful in evaluating melanomas associated with melanocytic nevi.

Traumatic neuromas of the penis: a clinical, histopathological and immunohistochemical study of 17 cases.

We present 17 penile traumatic neuromas. The mean patient age at presentation was 38 years (range 23-59 years). The most common site involved was the penile shaft. The lesions ranged from 1 to 7 mm in greatest dimension. The clinical diagnosis in all cases included condyloma acuminatum. In all cases, a history of trauma because of prior biopsy and/or circumcision was found. Histologically, all lesions showed similar features consisting of an increased number of dermal nerve bundles embedded within a fibrous stroma. Often, single or multiple Meissner corpuscle-like structures were noted in the papillary dermis. Our study suggests that circumcision or other forms of trauma to the skin of the penis likely plays an important role in the pathogenesis and clinical presentation of this peculiar neural neoplasm. We call attention to this entity because it is often clinically misdiagnosed as condyloma acuminatum.

A modified approach to the histologic diagnosis of onychomycosis.

BACKGROUND: Histologic examination of nail clippings with periodic acid-Schiff staining is the most sensitive diagnostic test for onychomycosis; however, difficulties in processing nail plates limit its use. In onychomycosis, fungi are most concentrated in the subungual hyperkeratosis rather than in the nail plate. We hypothesized that the diagnosis of onychomycosis could be effectively made from histologic examination of subungual hyperkeratosis alone. Specimens of subungual hyperkeratosis, unlike nail plates, can be processed in the same routine manner as skin specimens, allowing for the diagnosis of onychomycosis to be made more quickly and at lower cost. OBJECTIVE: We investigated whether the diagnosis of onychomycosis could be effectively made from histologic examination of subungual hyperkeratosis alone. METHODS: We selected all nail specimens submitted during an 8-month period to the New York University Dermatopathology Section for evaluation of onychomycosis that had subungual hyperkeratosis associated with the nail plate. Nail specimens were divided into two components: a subungual hyperkeratosis component and a nail plate component. The subungual hyperkeratosis was processed separately in a routine fashion and embedded in paraffin and examined. We determined the percentage of cases of onychomycosis in which hyphae were present in the subungual component. RESULTS: Sixty-six cases of onychomycosis were diagnosed histologically during the study period. Ninety-seven percent of these cases had hyphae in the subungual component. In 3% of cases, hyphae were present in the nail plate component but not in the subungual component. LIMITATIONS: This modified approach to diagnosing onychomycosis can only be utilized when an adequate amount of subungual hyperkeratosis is submitted. CONCLUSIONS: The diagnosis of onychomycosis can be effectively made from histologic examination of subungual hyperkeratosis alone in most cases. This method circumvents the need to process nail plates in the vast majority of cases of onychomycosis (97%), resulting in a more efficient, less costly, and technically easier way of diagnosing onychomycosis. Submitting ample amounts of subungual hyperkeratosis is essential to increasing the diagnostic yield of nail clippings.

Possible role of the bulge region in the pathogenesis of inflammatory scarring alopecia: lichen planopilaris as the prototype.

BACKGROUND: Lichen planopilaris (LPP) is the prototype of scarring alopecias that mainly target the infundibuloisthmic (bulge) region of hair follicle. Hair follicle stem cells have been shown to reside in the bulge. METHODS: We carried out this study to better define the possible pathogenetic role of the bulge in LPP. Thirty-five cases of LPP were studied. Multiple serial sections of biopsy specimens stained with hematoxylin and eosin, periodic acid Schiff-diastase, and Elastic van Gieson. The following immunostains were applied: CD3, CD4, CD8, CD1a, and Ki-67. Uninvolved follicles and normal scalp biopsy specimens served as normal controls. RESULTS: All cases showed a lichenoid lymphocytic infiltrate at the bulge region. The bulb area was spared. CD8(+) T cells were increased compared with CD4(+) T-cell population. Langerhans' cells were decreased. Proliferating stem cells, highlighted by Ki-67, showed a marked decrease in the bulge compared with uninvolved follicles. CONCLUSION: Our study supports the finding that in LPP, the inflammatory infiltrate mainly involves the bulge region, where the stem cells reside. Once this area is damaged, the hair loses its potential of regrowth with resulting scarring alopecia. This is in contrast with inflammatory non-scarring alopecias such as alopecia areata, where the bulb region is targeted, sparing the stem cells.