Elastophagocytosis: Underlying mechanisms and associated cutaneous entities

Role of Dermal Factors Involved in Regulating the Melanin and Melanogenesis of Mammalian Melanocytes in Normal and Abnormal Skin

Mammalian melanin is produced in melanocytes and accumulated in melanosomes. Melanogenesis is supported by many factors derived from the surrounding tissue environment, such as the epidermis, dermis, and subcutaneous tissue, in addition to numerous melanogenesis-related genes. The roles of these genes have been fully investigated and the molecular analysis has been performed. Moreover, the role of paracrine factors derived from epidermis has also been studied. However, the role of dermis has not been fully studied. Thus, in this review, dermis-derived factors including soluble and insoluble components were overviewed and discussed in normal and abnormal circumstances. Dermal factors play an important role in the regulation of melanogenesis in the normal and abnormal mammalian skin.

A Comprehensive Update of the Atypical, Rare and Mimicking Presentations of Mycosis Fungoides

Introduction

Mycosis fungoides (MF) is the most frequent subtype of primary cutaneous T cell lymphomas (pCTCL). The diagnosis may be particularly difficult in the early stages as well as in atypical and rare clinical presentations. Furthermore, MF may simulate a large variety of common dermatologic disorders and patterns, both histopathologically and clinically.

Methods

A literature search was performed to provide a comprehensive update on the rare and atypical MF manifestations as well as the dermatoses and dermatological patterns that could be imitated by MF.

Results

A total of 114 publications were found describing a series of different dermatoses and dermatological patterns mimicked by MF, as well as some particular localizations of MF lesions and dermatoses that occur in preexisting MF lesions.

Conclusions

The number of dermatoses that can be imitated by MF is ever-increasing. Patients with common dermatologic conditions that prove to be treatment refractory should be biopsied without delay, and sequentially as necessary, to prevent delay in diagnosis and progression of disease. Clinicopathologic correlation is the best way of diagnosis.

Functionally Heterogenous Macrophage Subsets in the Pathogenesis of Giant Cell Arteritis: Novel Targets for Disease Monitoring and Treatment

Giant cell arteritis (GCA) is a granulomatous large-vessel vasculitis that affects adults above 50 years of age. In GCA, circulating monocytes are recruited to the inflamed arteries. With cues from the vascular microenvironment, they differentiate into macrophages and play important roles in the pathogenesis of GCA via pro-inflammatory cytokine production and vascular remodeling. However, a deeper understanding of macrophage heterogeneity in GCA pathogenesis is needed to assist the development of novel diagnostic tools and targeted therapies. Here, we review the current knowledge on macrophage heterogeneity and diverse functions of macrophage subsets in the pathogenesis of GCA. We next discuss the possibility to exploit their heterogeneity as a source of novel biomarkers and as targets for nuclear imaging. Finally, we discuss novel macrophage-targeted therapies and future directions for targeting these cells in GCA.

Secondary Syphilis With Elastophagocytosis: An Unusual Histologic Finding

ABSTRACT

Elastophagocytosis is a characteristic finding of granulomatous and elastolytic disorders. It is defined by phagocytosed elastic fibers within histiocytes, multinucleated giant cells, or both. This finding has also been associated with certain medications, malignancies, inflammatory conditions, and infectious disorders. Although Drs Ragaz and Ackerman reported elastophagocytosis in a secondary syphilis lesion in a review of actinic granuloma in 1979, more recent publications have not recognized this finding. We present a case of elastophagocytosis within a lesion of secondary syphilis in a 65-year-old man. Biopsy from his left forearm demonstrated features of secondary syphilis including subtle vacuolar alteration with mild superficial and mid perivascular lymphoplasmacytic inflammation. There were interstitial giant cells with phagocytosed elastic fibers within the superficial dermis. Spirochete immunostain was positive with confirmatory Treponema pallidum IgG antibody and RPR titer. In this report, we present a unique case of secondary syphilis.

Histopathologic features of noninfectious granulomatous disorders involving the skin

Granulomatous dermatoses may represent primary skin inflammation or can serve as the harbinger of a multitude of underlying systemic disorders or drug reactions. Taken together with clinical findings, the microscopic features from skin biopsy can allow recognition of various patterns and facilitate a precise diagnosis. Accurate classification of entities in this category of inflammatory dermatoses may prompt clinicians to investigate for underlying systemic problems, thereby allowing the pathologist to add considerable value in the care of affected patients. This review article categorizes clinical and microscopic features of common and uncommon causes of noninfectious dermal and subcutaneous granulomatous inflammation.

Elastophagocytosis and interstitial granulomatous infiltrate are more common in extragenital vs genital lichen sclerosus

BACKGROUND

Genital and extragenital lichen sclerosus (LS) share similar histopathologic features. A recent small series documented elastophagocytosis uniquely in extragenital LS. We evaluated a larger series of LS for elastophagocytosis, elastic fiber loss, and other histopathologic features. We evaluated matrix metalloproteinase (MMP) expression to determine if these proteins play an etiologic role.

METHODS

Genital (n = 42) and extragenital (n = 41) LS biopsies were examined for histopathologic features, elastic fiber alteration (Verhoeff van Gieson staining), and MMP-2 and MMP-9 expression (immunohistochemistry).

RESULTS

Elastophagocytosis and an interstitial granulomatous pattern were significantly more common in extragenital LS than genital LS (43.9% vs 4.7% and 56.1% vs 9.5%). Extragenital LS had mild/focal elastic fiber loss (43.9%), while genital LS had moderate (61.9%) or marked (19%) loss. MMP-9 was diffusely expressed in histiocytes in both types of LS (genital 97.5%; extragenital 100%). Weak MMP-2 expression was seen in genital (58%) and extragenital (55%) LS.

CONCLUSIONS

Extragenital LS, but not genital LS, frequently exhibits elastophagocytosis and interstitial granulomatous infiltrate, and these patterns could contribute to elastic fiber destruction in extragenital LS. While MMP-2 and MMP-9 expression are common in LS, expression did not significantly differ depending on anatomic site and thus is unlikely to explain observed histopathologic differences.

Cutaneous disorders characterized by elastolysis or loss of elastic tissue

Along with collagen, elastic fibers are integral components of cutaneous connective tissue. A decrease in elastic fibers or loss thereof has been described in a number of clinically distinct skin diseases, both hereditary and acquired. In disorders associated with inflammation, elastophagocytosis is an important histological hallmark. Treatment is generally difficult.

A Case of Annular Elastolytic Giant Cell Granuloma Associated with Syphilis

Annular elastolytic giant cell granuloma (AEGCG) is a rare granulomatous skin disease characterized by annular patches with slightly raised borders, hypopigmented and/or atrophic centers found mainly on sun-exposed skin. Histologically, it is characterized by phagocytosis of elastic fibers by multinucleated giant cells. The pathogenesis of the disease is unclear. We report a case of 55-year-old man with AEGCG in association with syphilis, whose condition improved when hydroxychloroquine sulfate and topical tacrolimus were administered over a 2-month period.

Granulomatous & histiocytic dermatitides

Granulomas of the skin may be classified in several ways. They are either infectious or non-infectious in character, and they contain areas of necrobiosis or necrosis, or not. Responsible infectious agents may be mycobacterial, fungal, treponemal, or parasitic organisms, and each case of granulomatous dermatitis should be assessed histochemically for those microbes. In the non-infectious group, examples of necrobiotic or necrotizing granulomas include granuloma annulare; necrobiosis lipoidica; rheumatoid nodule; and lupus miliaris disseminates faciei. Non-necrobiotic/necrotizing and non-infectious lesions are exemplified by sarcoidosis; foreign-body reactions; Melkersson-Rosenthal syndrome; Blau syndrome; elastolytic granuloma; lichenoid and granulomatous dermatitis; interstitial granulomatous dermatitis; cutaneous involvement by Crohn disease; granulomatous rosacea; and granulomatous pigmented purpura. Histiocytic dermatitides that do not feature granuloma formation are peculiar reactions to infection, such as cutaneous malakoplakia; leishmaniasis; histoplasmosis; lepromatous leprosy; rhinoscleroma; lymphogranuloma venereum; and granuloma inguinale.

Mid-dermal elastolysis: A female-centric disease; case report and updated review of the literature

Background

Mid-dermal elastolysis (MDE) is a rare, yet well-defined clinical and histopathologic entity manifested by fine wrinkling of the skin and mid-dermal loss of elastic fibers. This disease predominantly affects young to middle-aged Caucasian females and although it has no reported systemic features, it is psychologically bothersome and can be of great cosmetic concern.

Methods

We report a case of a healthy 45 year-old female with widespread mid-dermal elastolysis. A literature search using the search terms “mid-dermal elastolysis,” “mid dermal elastolysis,” “middermal elastolysis,” and “elastophagocytosis” was conducted on Pubmed, using articles published from January 2008 until November 2014 to accompany Gambichler’s comprehensive 1977 to 2009 review of mid-dermal elastolysis. The references of relevant papers were reviewed and further cases included as appropriate.

Results

We review the clinical features and histological, ultrastructural, and immunohistochemical findings of MDE, as well as differential diagnoses. There are 13 new publications of MDE since 2008. The novel findings since Gambichler’s review are discussed and pathomechanisms revisited. Interestingly, given the striking female predominance of MDE, there is no known hormonal role in its etiology.