Intraepidermal proliferation of Merkel cells within a seborrheic keratosis: Merkel cell carcinoma in situ or Merkel cell hyperplasia?

Intradepidermal proliferation of Merkel cells without any dermal component has been interpreted as either a hyperplastic process secondary to chronic ultraviolet radiation or a neoplastic process, namely Merkel cell carcinoma (MCC) in situ. The recent criteria that have been proffered to diagnose MCC in situ, unfortunately, are identical to those that have been applied to Merkel cell hyperplasia in the past, posing a diagnostic quandary when faced with an intraepidermal proliferation of Merkel cells. Most previously reported cases of MCC in situ have occurred within associated epithelial lesion that includes solar (actinic) keratosis and squamous-cell carcinoma in situ. Similarly, Merkel cell hyperplasia has been reported to occur in association with a variety of epithelial lesions as well as on chronically sun-damaged skin. Herein, a case of an intraepidermal proliferation of Merkel cells within a seborrheic keratosis is presented accompanied by a discussion on whether the proliferation represents another case of Merkel cell carcinoma in situ or an incidental hyperplastic process on chronically sun-damaged skin.

Clinical and histopathological features of cutaneous manifestations of adult-onset Still disease.

Adult-onset Still disease (AOSD) is a rare autoinflammatory syndrome characterized by recurring fevers, arthralgia, and consistent laboratory abnormalities that include leukocytosis and hyperferritinemia. Skin findings accompany the disease in nearly 90% of the cases. Early reports described evanescent, pruritic, salmon-pink or urticarial lesions, referred to as the typical eruption of AOSD. Histopathologic findings consist of superficial perivascular dermatitis with varying number of interstitial neutrophils. Later reports described a more persistent rash that tended to be photodistributed, hyperpigmented, often in a linear configuration, sometimes in a rippled pattern, referred to as the atypical eruption of AOSD. The presence of individual necrotic keratinocytes in the upper spinous layer has been the consistent histopathologic finding. The persistent rash may not represent an atypical presentation of AOSD as recent reports indicate a high prevalence of the rash. Emerging data also suggest that patients with persistent eruption have a worse prognosis. The recognition of the clinical and histopathological findings of skin eruptions of AOSD may facilitate an earlier diagnosis, potentially improving disease outcome. Herein, clinical and histopathological features of cutaneous manifestation of AOSD in 2 Asian women are highlighted accompanied by a relevant review of the disease.

RB-pathway disruption is associated with improved response to neoadjuvant chemotherapy in breast cancer.

PURPOSE: We sought to determine whether dysregulation of the retinoblastoma (RB) tumor suppressor pathway was associated with improved response to neoadjuvant chemotherapy in breast cancer. EXPERIMENTAL DESIGN: An RB-loss signature was used to analyze the association between pathway status and pathologic complete response in gene expression datasets encompassing three different neoadjuvant regimens. Parallel immunohistochemical analysis of the RB pathway was conducted on pretreatment biopsies to determine the association with pathologic response to neoadjuvant chemotherapy. RESULTS: An RB-loss gene expression signature was associated with increased pathologic complete response in datasets from breast cancer patients treated with 5-fluorouracil/adriamycin/cytoxan (FAC; P < 0.001), T/FAC (P < 0.001), and Taxane/Adriaymcin (P < 0.001) neoadjuvant therapy encompassing approximately 1,000 patients. The association with improved response to neoadjuvant chemotherapy was true in both estrogen receptor (ER)-positive and ER-negative breast cancer. Elevated expression of p16ink4a is associated with the RB-loss signature (R = 0.493-0.5982), and correspondingly p16ink4a mRNA levels were strongly associated with pathologic complete response in the same datasets analyzed. In an independent cohort, immunohistochemical analyses of RB and p16ink4a revealed an association of RB loss (P = 0.0018) or elevated p16ink4a (P = 0.0253) with pathologic complete response. In addition, by Miller-Payne and clinicopathologic scoring analyses, RB-deficient tumors experienced an overall improved response to neoadjuvant chemotherapy. CONCLUSION: Disruption of the RB pathway as measured by several independent methods was associated with improved response to neoadjuvant chemotherapy. The RB-pathway status was relevant for pathologic response in both ER-positive and ER-negative breast cancer with similar results observed with multiple chemotherapy regimens. Combined, these data indicate that RB status is associated with the response to neoadjuvant chemotherapy in breast cancer and could be used to inform treatment.

Presence of broadly reactive and group-specific neutralizing epitopes on newly described isolates of Crimean-Congo hemorrhagic fever virus.

Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the genus Nairovirus of the family Bunyaviridae, causes severe disease in humans with high rates of mortality. The virus has a tripartite genome composed of a small (S), a medium (M) and a large (L) RNA segment; the M segment encodes the two viral glycoproteins, G(N) and G(C). Whilst relatively few full-length M segment sequences are available, it is apparent that both G(N) and G(C) may exhibit significant sequence diversity. It is unknown whether considerable antigenic differences exist between divergent CCHFV strains, or whether there are conserved neutralizing epitopes. The M segments derived from viral isolates of a human case of CCHF in South Africa (SPU 41/84), an infected tick (Hyalomma marginatum) in South Africa (SPU 128/81), a human case in Congo (UG 3010), an infected individual in Uzbekistan (U2-2-002) and an infected tick (Hyalomma asiaticum) in China (Hy13) were sequenced fully, and the glycoproteins were expressed. These novel sequences showed high variability in the N-terminal region of G(N) and more modest differences in the remainder of G(N) and in G(C). Phylogenetic analyses placed these newly identified strains in three of the four previously described M segment groups. Studies with a panel of mAbs specific to G(N) and G(C) indicated that there were significant antigenic differences between the M segment groups, although several neutralizing epitopes in both G(N) and G(C) were conserved among all strains examined. Thus, the genetic diversity exhibited by CCHFV strains results in significant antigenic differences that will need to be taken into consideration for vaccine development.

Cellular localization and antigenic characterization of crimean-congo hemorrhagic fever virus glycoproteins.

Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the genus Nairovirus of the family Bunyaviridae, causes severe disease with high rates of mortality in humans. The CCHFV M RNA segment encodes the virus glycoproteins G(N) and G(C). To understand the processing and intracellular localization of the CCHFV glycoproteins as well as their neutralization and protection determinants, we produced and characterized monoclonal antibodies (MAbs) specific for both G(N) and G(C). Using these MAbs, we found that G(N) predominantly colocalized with a Golgi marker when expressed alone or with G(C), while G(C) was transported to the Golgi apparatus only in the presence of G(N). Both proteins remained endo-beta-N-acetylglucosaminidase H sensitive, indicating that the CCHFV glycoproteins are most likely targeted to the cis Golgi apparatus. Golgi targeting information partly resides within the G(N) ectodomain, because a soluble version of G(N) lacking its transmembrane and cytoplasmic domains also localized to the Golgi apparatus. Coexpression of soluble versions of G(N) and G(C) also resulted in localization of soluble G(C) to the Golgi apparatus, indicating that the ectodomains of these proteins are sufficient for the interactions needed for Golgi targeting. Finally, the mucin-like and P35 domains, located at the N terminus of the G(N) precursor protein and removed posttranslationally by endoproteolysis, were required for Golgi targeting of G(N) when it was expressed alone but were dispensable when G(C) was coexpressed. In neutralization assays on SW-13 cells, MAbs to G(C), but not to G(N), prevented CCHFV infection. However, only a subset of G(C) MAbs protected mice in passive-immunization experiments, while some nonneutralizing G(N) MAbs efficiently protected animals from a lethal CCHFV challenge. Thus, neutralization of CCHFV likely depends not only on the properties of the antibody, but on host cell factors as well. In addition, nonneutralizing antibody-dependent mechanisms, such as antibody-dependent cell-mediated cytotoxicity, may be involved in the in vivo protection seen with the MAbs to G(C).