Histiocytic sarcoma with secondary involvement of the skin and expression of CD1a: evidence of indeterminate cell differentiation?

BACKGROUND: Histiocytic sarcoma is an exceedingly rare malignant neoplasm composed of cells with a monocyte/macrophage phenotype. In the current nosology of histiocytic neoplasms, histiocytic sarcoma is separate from indeterminate cell histiocytosis, a generally benign disorder characterized by proliferation of a CD1a+ and S-100+ population of cells lacking Birbeck granules usually limited to the skin. METHODS: We present a case of histiocytic sarcoma in a 64-year-old man presenting as a peritonsillar mass and secondarily involving the skin. RESULTS: The malignant cells in the extracutaneous foci of disease expressed macrophage-associated antigens including S-100 but were CD1a-. The malignant cells in the skin coexpressed CD1a and S-100 but lacked ultrastructural features of Langerhans cells, findings indicative of indeterminate cells. CONCLUSIONS: We discuss the clinical and histopathologic differential diagnosis in association with prior reported cases of histiocytic sarcoma, particularly in cases involving the skin and cases expressing the Langerhans cell-associated antigen CD1a.     

Taponamiento cardíaco por sarcoma de Kaposi

—Kaposi's sarcoma is a systemic angiomatous tumor that generally affects individuals over 50 years of age; it is mainly observed in male patients. Few cases of visceral involvement have been described in its classic form. In this work, we describe a case of classic Kaposi's sarcoma with disseminated skin lesions, involvement of multiple internal organs and fatal evolution. The cause of death was a cardiac tamponade caused by the Kaposi's sarcoma lesions that developed in the epicardium and the pericardium.     

A case of intraepidermal Merkel cell carcinoma within squamous cell carcinoma in-situ: Merkel cell carcinoma in-situ?

We report a case of a 79-year-old Caucasian male who presented with a wrist lesion of combined intraepidermal Merkel cell carcinoma and squamous cell carcinoma in-situ. The two tumors were tightly admixed and distinct, and both were without any dermal or invasive components. No features of transition between the two tumors were seen. We suggest the term Merkel cell carcinoma in situ for tumors that demonstrate exclusive intraepidermal proliferation of neuroendocrine cells.     

Obligatory roles of filamin A in E-cadherin-mediated cell–cell adhesion in epidermal keratinocytes

BackgroundExtracellular Ca²⁺ (Ca_o²⁺)-induced E-cadherin-mediated cell–cell adhesion plays a critical role in promoting differentiation in epidermal keratinocytes. Our previous studies show that the calcium-sensing receptor (CaR) regulates keratinocyte cell–cell adhesion and differentiation via Rho A-mediated signaling. CaR forms a protein complex with Rho A, guanine nucleotide exchange factor Trio, and a cytoskeletal actin-binding protein, filamin A, at the cell–cell junctions in response to elevated Ca_o²⁺ levels. Filamin A has the ability to interact directly with CaR, Trio, and Rho and mediate CaR-dependent signaling events.ObjectiveThis study was conducted to investigate the roles of filamin A and Trio in regulating Ca_o²⁺-induced Rho activation and intercellular adhesion.MethodsExpression of filamin A and Trio in keratinocytes was inhibited by siRNA. Its effects on Ca_o²⁺-dependent junction formation and adhesion complex formation were evaluated by fluorescence immunostaining and immunoprecipitation. Endogenous Rho activity and expression of keratinocyte differentiation markers were also examined. The significance of the physical interactions of filamin A with Trio and Rho was assessed in dominant-negative inhibition studies.ResultsInhibiting filamin A expression blocked the formation of CaR-Rho A-Trio-E-cadherin protein complex. Knockdown of filamin A or Trio inhibited Ca_o²⁺-induced membrane localization and activation of Rho A, formation of the E-cadherin–catenin adhesion complex, and keratinocyte terminal differentiation. Expressing dominant-negative peptides disruptive to the endogenous filamin–Trio, filamin–Rho, and CaR–filamin interactions suppressed the formation of adherens junctions.ConclusionThrough physical interactions with CaR, Trio and Rho, filamin A generates a scaffold for organizing a signaling complex that promotes E-cadherin-mediated cell–cell adhesion and keratinocyte differentiation.     

Nevoid basal cell carcinoma syndrome or multiple hereditary infundibulocystic basal cell carcinoma syndrome?

We present a case of nevoid basal cell carcinoma syndrome, also known as Gorlin syndrome, or basal cell nevus syndrome, which clinically follows a course more consistent with multiple hereditary infundibulocystic basal cell carcinomas or multiple hereditary trichoepitheliomas. The following article describes the case in detail and gives an overview of other genodermatosis, which were initially considered in the differential and which may be linked pathogenetically.     

Penile intraepithelial neoplasia overlying Kaposi's sarcoma lesions: role of viral synergy?

Several viral agents have been detected in the lesional tissue of Kaposi's sarcoma (KS). Their precise oncogenic role remains to be determined. A 32-year-old heterosexual man with acquired immunodeficiency syndrome (AIDS) who had penile lesions of KS with overlying epithelial changes characteristic of intraepithelial neoplasia associated with concurrent infection by human papillomavirus (HPV) and human herpesvirus 8 (HHV-8) is reported. The absence of viral DNA from uninvolved skin suggests that this coinfection is more than coincidental and may involve synergy between these viruses, as has already been suggested for HPV and herpes simplex 2 virus.     

Nevus cell maturation or atrophy?

Nevus cells show considerable variation in their appearance, depending on their localization in epidermis, upper dermis, or deep dermis. The difference in appearance of nevus cells when located superficially or in the deep dermis has been referred to as nevus cell "maturation." The aim of this study is to objectify morphological differences between nevus cells in epidermis, upper dermis, and deep dermis by means of a morphometric study at light- and electron microscopic levels. The results show that there is a decrease in number and size of all structures except for mitochondria and microfilaments. These findings are consistent with atrophy. The concepts of maturation, differentiation, and atrophy are also discussed.     

Association of haptoglobin phenotypes with the development of Kaposi��s sarcoma in HIV patients

Kaposi's sarcoma (KS) is a rare cutaneous tumor caused by human herpes virus-8 (HHV-8) infection that preferentially develops in case of severe immunosuppression, such as in HIV/AIDS disease. Haptoglobin (Hp), a polymorphic multifunctional plasma protein, exerts several immunomodulatory effects and is characterized by a genetic polymorphism leading to three major phenotypes (Hp 1-1, Hp 2-1 and Hp 2-2). This study investigated the influence of Hp genetic polymorphism on the development of KS in HIV-positive patients. 661 HIV patients were enrolled in the study with a median age of 35?years and a median follow-up time of 57?months. Hp phenotyping was performed using hemoglobin-supplemented starch gel electrophoresis. In case of low Hp concentration high pressure gel permeation chromatography (HPGPC) was used. The Hp 1-1 phenotype was associated with a significant higher risk of KS compared to the combined group of Hp 2-1 and Hp 2-2 patients (p?相似文献   

Human herpesvirus 8 investigations: a role in the clinical management of Kaposi's sarcoma?

Kaposi's sarcoma (KS) is a vascular tumour associated with infection by human herpesvirus 8 (HHV-8). Most of the recent studies on KS have focused on the epidemiology and molecular biology of HHV-8. However, the contribution of virological investigations into HHV-8 to the clinical management of KS has been poorly evaluated so far. From a diagnostic point of view, HHV-8 currently appears as a useful tool for distinguishing KS from its mimics. Seroconversion to antibodies against HHV-8 may predict the development of KS in susceptible individuals, and reduction of HHV-8 viraemia is associated with therapies effective against KS. Further prospective studies are still required to determine the role of serological or genotypic investigations into HHV-8 in the prevention of KS and in KS response to therapy.