Critical Review-A Tribute to Louis Brocq Lymphomatoid Papulosis, the Key in Exploring the Relationship of Parapsoriasis and Mycosis Fungoides.

ABSTRACT: Both parapsoriasis and LyP appear clinically as inflammatory dermatoses with a paradoxical link to cMF. A key element in addressing the relationship of parapsoriasis and MF were the results of the French and Dutch long-term registries tracking the emergence of lymphomas in the setting of LyP. Both cMF and cALCL emerged almost equally in these long-term studies. This ultimately supports that the stem cells in both cMF and cALCL are probably derived from a common stem cell shared by CD4+/CD8+ memory stem cells defining cMF and CD30+ stem cells defining cALCL. The discovery of inducible Skin Associated Lymphoid Tissue (iSALT) mesenchymal hubs incorporating Tregs, with their pleiotropic functions represents a paradigm shift and formed a translational tool in this analysis of the paradox. LyP can be recast as activated inhibitory lymphomatoid T-cell hubs derived from inducible iTregs in iSALT and the source of the common stem cell LyP line. iSALT Treg integrated mesenchymal hubs provided an emerging translational tool in redefining integrated lymphomatoid pathways. Brocq's complex scheme defining parapsoriasis as hybrid inflammatory dermatoses with a paradoxical link to cMF became a template to preserve parapsoriasis as a clinical diagnosis. Two major iSALT Treg generated inhibitory integrated lymphomatoid hubs emerged. The major CD30+TNF lymphomatoid hub has been linked to cALCL. Clinically defined chronic regressing and relapsing parapsoriasis with the histopathology of patch stage MF can be redefined as lymphomatoid parapsoriasis. This twin inhibited oncogenic memory based hub is defined by Treg modulated, CD4+/CD8+memory linked PD-1/DL-1 cytoxic complex and lichenoid histopathology.

Myopericytomatosis: A rare entity mimicking other vascular tumours and malformations.

Myopericytoma is a rare tumour which typically presents as a benign lesion that mimics features of other more common vascular tumours and malformations. We present a case of a symptomatic diffuse myopericytomatosis of the left abdomen presenting as multiple subcutaneous vascular tumours detected on ultrasound and treated with ultrasound-guided sclerotherapy.

Eruptive Necrotizing Infundibular Crystalline Folliculitis: An Expression of an Abortive Sebaceous Follicular Repair Pathway Linked to Committed Infundibular Stem Cells?

ABSTRACT: Necrotizing infundibular crystalline folliculitis is a rare entity, which is a distinctive clinical and histopathological entity. Eruptive yellow waxy umbilicated folliculocentric plugs clinically correspond to pale crystalline filaments embedded in an amorphous sebum-rich material. Remarkably, only the superficial infundibular ostia remain, and the distended cavity is devoid of a follicular or sebaceous gland remnant. The pathogenesis of this enigmatic event remains to be established. The emergence of necrotizing infundibular crystalline folliculitis (NICF) as a paradoxical side effect of antitumor inhibitors epidermal growth factor receptor vascular endothelial growth factor and more recently programmed death-1 represents the expression of altered molecular pathways that underpin the pathogenesis of NICF. To explore these pathways, it is necessary to explore the hierarchy of follicular stem cells, particularly the potential role of committed infundibular stem cells that play a key role in wound healing. Committed infundibular stem cells are closely linked to the sebaceous gland stem cell axis, and this has relevance in the process of homeostatic repair of sebaceous follicles in the wake of folliculitis. The unscheduled modulation of this infundibular homeostatic sebaceous repair axis by epidermal growth factor receptor vascular endothelial growth factor, and programmed death-1 may lead to an aberrant outcome with metaplasia of infundibular keratinocytes to sebocytes. In the absence of sebaceous gland differentiation, these metaplastic infundibular sebocyte cells would lead to the consumption and loss of the infundibulum as a result of holocrine sebum production. This conceptual pathogenic pathway for NICF is constructed by incorporating recent advances in the fields of follicular stem cells, wound repair, follicular homeostasis, regulatory T cells, and molecular pathways linked to the biologicals inducing NICF.

Keratoacanthoma, committed stem cells and neoplastic aberrant infundibulogenesis integral to formulating a conceptual model for an infundibulocystic pathway to squamous cell carcinoma.

Keratoacanthomas (KAs) are distinctive tumors that are defined by their clinical and histopathological features. Their relationship and distinction from squamous cell carcinoma (SCC), however, remain controversial. All cytogenic and immunohistochemical markers that have been applied in this quest have failed. A close relationship of KAs to hair follicles has been recognized. The descriptive term infundibulocystic or infundibular SCC was introduced to define a more broad-based pathway encompassing KAs. The follicular infundibulum roles in respect to neoplasia and wound healing are important elements in understanding the pathogenesis of KAs. Mouse models for KA have provided insights into the relationship of KA to follicles and SCCs. These advances and together with the diverse clinical and histopathological aspects of KA have contributed to the formulation of a conceptual pathway. The central element is that ultraviolet (UV)-mutated or activated committed infundibular stem cells are driven by the combination of a mutated oncogenic RAS pathway linked with the Wnt/beta-catenin pathway responsible for stem cell maintenance, hair follicle development, wound healing and driving KA proliferation and terminal keratinization. The existence and activation of this mutated pathway may form the basis of the paradoxical emergence of KAs and SCCs in patients receiving BRAF and PD-1 inhibitor therapy.

Onycholemmal variant of keratoacanthoma centrifugum marginatum as an expression of mutated committed stem cells in a conceptual pathway.

We describe a 43-year-old woman with a 10-year history of grossly hyperkeratotic nodules which progressively extended over the right ring finger. These involuted leaving pale, atrophic skin in their wake. At presentation, the advancing border had an arciform series of nodules in the pattern of keratoacanthoma centrifugum marginatum. The presence of filiform keratinisation that encased the nail plate, gross onychogryphotic masses of keratin on the ventral finger surface and a flat nail-like plate of keratin on the dorsal finger surface were distinctive features. Skin biopsy showed epidermal acanthosis, gross papillomatous cutaneous horn formation that had onycholemmal features. The pathology differed from keratoacanthoma and was not crateriform or infundibulocystic. Although HPV was not detected on immunohistochemistry, pathogenesis may still represent an HPV-related transfection of onycholemmal keratin committed stem cells producing an onycholemmal variant of keratoacanthoma centrifugum marginatum. A conceptual model linked to advances in follicular stem cell biology is formulated to explore this case.

Granuloma formation following cyanoacrylate glue injection in peripheral veins and arteriovenous malformation.

Background: Cyanoacrylate adhesive closure is a technically simple alternative to endothermal ablation of peripheral veins. N-butyl cyanoacrylate is delivered via catheters or by percutaneous injection resulting in occlusion of target veins. The local tissue reaction or the systemic immune response that may follow have not been characterised. Aim: To characterise the late local tissue reaction to N-butyl cyanoacrylate glue injected in peripheral vessels. Methods: Biopsies were obtained from two patients. In patient one, distal tributaries of the great saphenous vein were injected with VenaBlock™ glue under ultrasound guidance. Ultrasound-guided incisional biopsies were performed at one week, six weeks and 12 months. In patient two, a peripheral arterio-venous malformation was injected with Venablock™ and biopsy was performed 12 months later. Histological analysis was performed using haematoxylin and eosin and immunofixation with CD-4, CD-31, CD-34, CD-68 and D2-40. Results: Echogenic material with a strong shadow artefact consistent with the injected N-butyl cyanoacrylate was observed on ultrasound on all follow-up occasions. Biopsies taken at one week showed intravascular glue without histiocytes. Biopsies at six weeks showed isolated foreign body histiocytes coating intravascular fibrillary glue spicules but no granuloma formation. The one-year biopsies showed extravascular changes including fibrosis, lymphoid aggregates and multiple extravascular foreign body cavitated granulomas. Some vessel lumens contained residual spicules of glue but no intravascular granulomas. The extravascular granulomas were deeply located, asymptomatic and not complicated by clinical ulceration. Histologically, there was no evidence of transepidermal elimination. Conclusion: Extravascular foreign body cavitated granulomas containing spicules of glue with fibrosis and lymphoid aggregates occur as a delayed finding following the use of N-butyl cyanoacrylate.

Differential proteomic analysis of actinic keratosis, Bowen's disease and cutaneous squamous cell carcinoma by label-free LC-MS/MS.

BACKGROUND: The boundaries between actinic keratosis (AK), Bowen's disease (BD), and cutaneous squamous cell carcinoma (cSCC) are sometimes not clear. Large-scale proteomic profiling studies of these lesions are also non-existent. OBJECTIVE: To evaluate proteomic changes between normal epidermis, AK, BD and cSCC that could support a molecular classification and improve our understanding of disease progression. METHODS: Microdissected formalin-fixed paraffin embedded samples of normal epidermis (n = 4, pooled), AK (n = 10), BD (n = 10) and cSCC (n = 10) were analyzed by mass spectrometry. Following normalization and multiple testing adjustments, differential abundance analysis was performed using Linear Models for Microarray data. Proteins were filtered for significance (adjusted p-value ≤ 0.05) and fold change of at least ±1.5. Comparative bioinformatics analysis was performed using Ingenuity Pathway Analysis (IPA) software. Proteomic findings were subsequently substantiated using immunohistochemistry. RESULTS: 2073 unique proteins were identified. cSCC had the highest number of differentially abundant proteins (63 proteins) followed by BD (58 proteins) and AK (46 proteins). Six proteins (APOA1, ALB, SERPINA1, HLA-B, HP and TXNDC5) were differentially abundant in cSCC compared to AK. Immunohistochemical analysis corroborated changes in MIF, RPL37A and TXNDC5. IPA analysis predicted that cell proliferation, angiogenesis and inflammatory reactions were significantly activated in cSCC compared to BD and AK. Cell death and DNA damage were predicted to be inhibited in BD. CONCLUSION: Our study supports the concept that AK and BD are precursors of cSCC. The identification of proteome changes indicates disruption of repair, pro-apoptotic, and tumor promoting pathways. Our findings will help select targets for classification and treatment.

In Silico Analysis Validates Proteomic Findings of Formalin-fixed Paraffin Embedded Cutaneous Squamous Cell Carcinoma Tissue.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is a common type of skin cancer but there are no comprehensive proteomic studies on this entity. MATERIALS AND METHODS: We employed liquid chromatography coupled with tandem mass spectrometry (MS/MS) using formalin-fixed paraffin-embedded (FFPE) cSCC material to study the tumor and normal skin tissue proteomes. Ingenuity Pathway Analysis (IPA) was used to interpret the role of altered proteins in cSCC pathophysiology. Results were validated using the Human Protein Atlas and Oncomine database in silico. RESULTS: Of 1,310 unique proteins identified, expression of an average of 144 and 88 proteins were significantly (p<0.05) increased and decreased, respectively, in the tumor samples compared to their normal counterparts. IPA analysis revealed disruptions in proteins associated with cell proliferation, apoptosis, and migration. In silico analysis confirmed that proteins corresponding to 12 antibodies, and genes corresponding to 18 proteins were differentially expressed between the two categories, validating our proteomic measurements. CONCLUSION: Label-free MS-based proteomics is useful for analyzing FFPE cSCC tissues.

Cutaneous adverse effects of hormonal adjuvant therapy for breast cancer: a case of localised urticarial vasculitis following anastrozole therapy and a review of the literature.

Hormonal therapy with either tamoxifen or aromatase inhibitors is commonly used to treat women with breast cancer in both the adjuvant and recurrent disease setting. Cutaneous adverse reactions to these drugs have been rarely reported in the literature. We report an unusual case of urticarial vasculitis following the aromatase inhibitor anastrozole that localised to the unilateral trunk and mastectomy scar, and review the literature on the cutaneous adverse effects of hormonal therapy for breast cancer.

Neurotropic T-cell lymphocytosis: a cutaneous expression of CLIPPERS.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory disease of the central nervous system that predominantly involves the pons and cerebellum and that improves with immunosuppressive treatment. Only recently described, the etiology is unknown, diagnosis is difficult and long-term neurological sequelae may occur without aggressive treatment. Herein, we describe a 59-year-old woman who presented with subcutaneous nodules affecting her face, trunk, limbs and an indurated annular erythematous lesion on her forearm. This was associated with marked dysesthesia of her skin, refractory to treatment. There was a 4-year history of dysequilibrium, vertigo, truncal and gait ataxia with progressive neurological symptoms. Skin biopsy of the annular nodular lesion showed a lymphohistiocytic infiltrate in dermis and subcutis with a striking lymphocyte-dominant infiltrate that was perineural and formed a nodular collection extending along a prominent subcutaneous nerve. Immunophenotyping indicated a marked predominance of T cells that were CD3 positive with a 2 : 1 CD4 : CD8 ratio. Scattered histiocytes were present but no well-formed granulomas or vasculitis. Magnetic resonance imaging studies showed changes in the pontine, brain stem and cerebellar region, which subsequently were defined as characteristic for CLIPPERS, but no brain biopsy was pursued. The marked neural skin symptoms and the cutaneous histopathological findings indicate that the skin may be an additional target organ in CLIPPERS, and the immune response may be directed against a common neural antigen. In radiologically typical CLIPPERS, identification of clinical skin lesions particularly subcutaneous nodules and biopsy may potentially form a basis for tissue diagnosis in this syndrome.

Calcinosis cutis following contact with calcium chloride solution.

Calcinosis cutis is the deposition of insoluble calcium in the cutaneous tissue. Calcinosis cutis can be classified as metastatic, dystrophic, idiopathic or exogenous. We report a 48-year-old white man who was dismantling a portable ice skating rink when calcium chloride solution from the pipes spilt onto his clothing. Several days later, he started to develop mildly pruritic erythematous papules, some studded with white deposits and some with umbilication over the exposed areas corresponding to the spillage of the calcium chloride solution. Histological features revealed interstitial fibrohistiocytic reaction with calcium-encrusted degenerated collagen bundles in the dermis which was further confirmed by von Kossa stain. He was commenced on topical corticosteroid cream twice daily and the lesions cleared completely between 6 to 10 weeks.

Plaque-like cutaneous mucinosis: case report and literature review.

Midline mucinosis was observed in a 14-year-old man, which was confined to the midline of the back and appeared as asymptomatic, nonindurated, hyperpigmented plaques. Skin biopsies showed prominent interstitial mucinosis with perivascular lymphocytic infiltration. A literature review of plaque-like mucinosis revealed 14 previous cases with this distinct presentation that may overlap with reticular erythematous mucinosis and connective tissue disease. Midline mucinosis has been previously reported in prepubertal children but is rare.

Enfuvirtide injection site reactions: a clinical and histopathological appraisal.

BACKGROUND/OBJECTIVES: Enfuvirtide was the first of a new class of antiretroviral agents termed 'fusion inhibitors' used for the treatment of HIV-1 infection. Enfuvirtide is administered subcutaneously and injection site reactions (ISR) are commonplace (98%). The aim of this study was to analyse in detail the histopathological changes associated with striking ISR seen in four patients. METHODS: Biopsies were obtained at various times post-injection and were reviewed histologically. The changes in epidermal, dermal and subcutaneous connective tissue and the presence and nature of the inflammatory cellular infiltrate were noted. An immunohistochemical assessment was undertaken. RESULTS: All biopsy specimens demonstrated striking changes in the dermal connective tissue. Alteration in collagen was the most prominent feature and resembled a morphoea/scleroderma-like process. These changes persisted well beyond cessation of enfuvirtide (>1 year). The relative populations of dermal dendritic cells (DDC) (types 1 (Factor XIIIa) and 2 (CD34+)) were analysed and a reciprocal relationship between DDC subpopulations was observed akin to that observed in other sclerosing and fibrosing conditions. CONCLUSION: This study details histopathological changes associated with enfuvirtide ISR. We postulate that changes in DDC populations may contribute to the pathogenesis of the sclerotic process observed with enfuvirtide ISR.