Epithelial proliferation in inflammatory skin disease is regulated by tetratricopeptide repeat domain 7 (Ttc7) in fibroblasts and lymphocytes.

BACKGROUND: Mutations in tetratricopeptide repeat domain 7A (TTC7A) and its mouse orthologue, Ttc7, result in a multisystemic disease, mostly affecting the epithelial barriers and immune system. Despite successful hematopoietic stem cell transplantation, ongoing progression of gastrointestinal manifestations can be life-threatening in TTC7A-deficient patients. OBJECTIVE: We sought to identify whether TTC7A mutations dysregulate epithelial cells only or whether a cell-intrinsic defect in lymphocytes or other cells contributes to disease manifestations. METHODS: Ttc7-mutated (Ttc7fsn/fsn) mice were crossed to generate double-mutant (Rag2-/-Ttc7fsn/fsn) and triple-mutant (Rag2-/-IL2rg-/-Ttc7fsn/fsn) mice. These models, together with bone marrow chimeras, were used to explore the role of adaptive and innate lymphocytes in the flaky skin phenotype. The effect of the Ttc7fsn/fsn mutation on stromal cells was tested in a xenograft model in conjunction with transcriptomic analysis of Ttc7fsn/fsn fibroblasts. RESULTS: We observed that the severity of epithelial hyperproliferation was accentuated by lymphocytes, whereas the phenotype was not induced by transfer of Ttc7-mutated hematopoietic cells. Furthermore, mice completely lacking the lymphocytic compartment were not protected from epithelial hyperproliferation. Ttc7-mutated mouse fibroblasts expressed increased transcript levels of insulin-like growth factor 1 (Igf1) and the antimicrobial protein regenerating islet-derived protein 3γ (Reg3γ). In a xenograft model Ttc7-mutated fibroblasts markedly increased epithelial proliferation of keratinocytes. Thus Ttc7-mutated fibroblasts were identified as potent instigators of epithelial hyperproliferation. CONCLUSION: Our results reveal a previously unsuspected fundamental cell-extrinsic role of Ttc7. We have identified potential candidates for molecularly targeted treatment strategies that will need to be evaluated in future preclinical studies.

Synergistic Bcl-2 inhibition by ABT-737 and cyclosporine A.

Survival of lymphocytes and melanocyte stem cells critically depends on B cell lymphoma 2 (Bcl-2). In T lymphocytes, a basal calcineurin activity maintains Bcl-2 expression in naïve cells, and the activation of the calcineurin pathway orchestrates the regulation of the intrinsic apoptosis pathway after antigen recognition. Therefore, calcineurin inhibitors might potentiate the pro-apoptotic effect of pharmacological Bcl-2 inhibitors on lymphatic cells. In vitro, a reduced Bcl-2 expression in lymphocytes exposed to calcineurin inhibitors increased their sensitivity to the small molecule Bcl-2 inhibitor ABT-737. This correlated with an augmented pro-apoptotic activity of ABT-737 on lymphocytes in combination with cyclosporine A in naïve mice in vivo. Interestingly, similar processes were observed in melanocytes. ABT-737 induced a fur depigmentation at the site of injection, and this effect was expanded to a generalized depigmentation in combination with cyclosporine A. Thus, inhibiting calcineurin increases the pro-apoptotic potency of ABT-737 in cells depending on Bcl-2 for survival. The increased efficacy of Bcl-2 inhibitors in combination with cyclosporine A might be relevant to exploit their anti-neoplastic and immuno-modulatory properties.

Primary cutaneous CD8(+) small- to medium-sized lymphoproliferative disorder in extrafacial sites: clinicopathologic features and concept on their classification.

Three cases with CD8+ small- to medium-sized lymphoproliferations in the skin at extrafacial sites are described. Clinically, the patients presented with papulonodular or plaque-like lesions without preceding patches. Histopathologically, nonepidermotropic nodular or diffuse infiltrates were composed of small- to medium-sized pleomorphic lymphocytes, which expressed CD8 (more than 80% of the cells) and granzyme B (60%-70% of the cells), but were negative for CD4, CD30, and CD56. There was no association with Epstein-Barr virus. A clonal T-cell population was detected in 2 patients. Staging examinations did not reveal extracutaneous involvement. The 2 patients with solitary lesions underwent complete remission after radiation therapy, whereas 1 patient developed multifocal lesions and several recurrences. These CD8+ small- to medium-sized lymphoproliferations of the skin at extrafacial sites may belong to a spectrum of phenotypically and prognostically heterogeneous cutaneous small- to medium-sized lymphoid proliferations, which are characterized by an indolent course in most patients.

T cell-mediated acute localized exanthematous pustulosis caused by finasteride.

A 21-year-old man presented with multiple erythematous nonfollicular papules partially confluent to plaques on his breast and lower abdomen that had been present for 1 month. Grouped pustules were present under the right breast. The patient had been taking finasteride over the past 3 months for androgenetic alopecia. His medical history was negative for psoriasis. Our initial differential diagnosis included dyskeratosis follicularis Darier, allergic contact dermatitis, infectious folliculitis, varicella zoster virus infection, fixed drug eruption, and IgA pemphigus. The white blood cell count and differential were within the normal limits. Results of viral cultures and PCR, as well as bacterial and fungal cultures of skin lesions proved negative. A lesional biopsy specimen showed a slight psoriasiform acanthosis in association with spongiosis and infiltration of both the epidermis and dermis by neutrophils and eosinophils, resulting in formation of subcorneal, intraepidermal, and subepidermal pustules. The results of direct immunofluorescence were negative, excluding an IgA pemphigus. The result of a lymphocyte transformation test was positive for finasteride. On the basis of the time relationship between the administration of finasteride and the development of the skin disease in combination with symptoms resolution on cessation of the drug, the histologic findings, and the positive lymphocyte transformation test result, we consider this to be an unusual type of acute generalized exanthematous pustulosis defined as acute localized exanthematous pustulosis caused by finasteride. Within 4 weeks after withdrawal of finasteride, the rash resolved without any specific therapy. Transient discrete residual hyperpigmentation and scaling were present. The patient refused an oral provocation challenge.

Spitzoid melanoma and micrometastases in two lymph node regions: a critical situation.

Atypical Spitz tumors can hardly be differentiated from spitzoid melanoma. CGH might help in the differential diagnosis. An 8 year old child with an atypical Spitz tumor (with a CGH pattern compatible with melanoma) of 8.0 mm Breslow thickness and micrometastases in two lymph node regions was seen at our department. The management and prognosis of atypical Spitz tumors is controversial, and aggressive procedural steps similar to melanoma are usually not recommended. Even performing sentinel lymph node biopsy has been questioned. After extensive interdisciplinary consultations, we did not recommend resection of both lymph node regions and chose instead to follow-up with regular whole-body MRI and adjuvant treatment with pegylated interferon. Treatment decisions for atypical Spitz tumors are a major medical and ethical challenge due to the limited available data.

Trauma as triggering factor for development of melanocytic nevi.

The mechanisms for the development of acquired melanocytic nevi remain mostly unclear. Here we report a case of eruptive nevi that developed after localized superficial trauma, and review the currently known cellular and triggering factors for acquired melanocytic nevi. A 66-year-old woman presented a linear arrangement of pigmented macules on her left calf that developed after a bloodless skin erosion on the same spot, resulting from friction with the lining of a ski boot. Dermatopathology identified multiple junctional proliferations of single or small nest-forming melanocytes with bridging, pigment incontinence and moderate cellular atypia. The number of a person's nevi correlates with age, race and genetics, but blistering diseases, scarring processes, light exposure and immunosuppression can contribute to nevocellular growth as well. Damaged keratinocytes and inflammatory cells can release growth factors inducing nevus cell proliferation, and immunosuppression could end cellular surveillance keeping preexisting nevus cell nests in check. We conclude that in predisposed patients, the trigger for eruptive nevi can be reduced to a simple localized minor trauma.

The rash that becomes purpuric, petechial, hemorrhagic, or ecchymotic.

Hemorrhagic rashes are observed in a wide variety of conditions, ranging from harmless to life-threatening. This review offers a stepwise approach, which helps limit the possible differential diagnoses based on the clinical manifestations and the clinical picture. The most common and most important conditions, including infectious, coagulation and embolic disorders, vasculitides, and vasculopathies, are briefly reviewed focusing on morphology. Dermatologists often need to distinguish among infectious, reactive, or autoimmune etiologies of the rash and determine if the condition is dangerous or even life-threatening in order to make the right decision. Dermatologic expertise provides vital input in the diagnosis and care of complex interdisciplinary patients, such as those with sepsis, purpura fulminans, and thrombotic thrombocytopenic purpura.

Symplastic glomus tumor - a rare but distinct benign histological variant with analogy to other 'ancient' benign skin neoplasms.

A 78-year-old woman presented with a nail deformity of the index finger of the left hand associated with paroxysmal pain upon cold exposure. Histologically, a well-circumscribed tumor of 3 mm diameter was found in the dermis. The neoplastic cells in some areas were of pronouncedly variable size and cytomorphology, mostly epithelioid in shape, with eosinophilic cytoplasm and indistinctly defined cell borders. Pronounced nuclear pleomorphism and atypia were striking features, but no mitotic figures were noted. Multinuclear cells were present as were numerous small-to-medium vessels throughout the tumor. The tumor stroma showed myxoid areas. Immunohistochemistry showed cytoplasmic and membranous expression of smooth muscle actin and vimentin. The histological features and immunoprofile were consistent with the diagnosis of symplastic glomus tumor, a rare histological variant, which has been defined as a glomus tumor exhibiting marked nuclear atypia, in the absence of any other criteria for malignancy. The biological behavior of the tumor is benign. It is essential to differentiate this entity from malignant glomus tumor, which has metastatic potential. Even prominent cellular atypia and nuclear pleomorphism in a glomus tumor as in our case is not a marker of malignancy in the absence of additional criteria.

Enhanced Fatty Acid Scavenging and Glycerophospholipid Metabolism Accompany Melanocyte Neoplasia Progression in Zebrafish.

Alterations in lipid metabolism in cancer cells impact cell structure, signaling, and energy metabolism, making lipid metabolism a potential diagnostic marker and therapeutic target. In this study, we combined PET, desorption electrospray ionization-mass spectrometry (DESI-MS), nonimaging MS, and transcriptomic analyses to interrogate changes in lipid metabolism in a transgenic zebrafish model of oncogenic RAS-driven melanocyte neoplasia progression. Exogenous fatty acid uptake was detected in melanoma tumor nodules by PET using the palmitic acid surrogate tracer 14(R,S)-18F-fluoro-6-thia-heptadecanoic acid ([18F]-FTHA), consistent with upregulation of genes associated with fatty acid uptake found through microarray analysis. DESI-MS imaging revealed that FTHA uptake in tumors was heterogeneous. Transcriptome and lipidome analyses further highlighted dysregulation of glycerophospholipid pathways in melanoma tumor nodules, including increased abundance of phosphatidyl ethanolamine and phosphatidyl choline species, corroborated by DESI-MS, which again revealed heterogeneous phospholipid composition in tumors. Overexpression of the gene encoding lipoprotein lipase (LPL), which was upregulated in zebrafish melanocyte tumor nodules and expressed in the majority of human melanomas, accelerated progression of oncogenic RAS-driven melanocyte neoplasia in zebrafish. Depletion or antagonism of LPL suppressed human melanoma cell growth; this required simultaneous fatty acid synthase (FASN) inhibition when FASN expression was also elevated. Collectively, our findings implicate fatty acid acquisition as a possible therapeutic target in melanoma, and the methods we developed for monitoring fatty acid uptake have potential for diagnosis, patient stratification, and monitoring pharmacologic response. SIGNIFICANCE: These findings demonstrate the translational potential of monitoring fatty acid uptake and identify lipoprotein lipase as a potential therapeutic target in melanoma.

Consequences of p16 tumor suppressor gene inactivation in mycosis fungoides and Sézary syndrome and role of the bmi-1 and ras oncogenes in disease progression.

In examining the expression of oncogenes and tumor suppressor genes in mycosis fungoides and Sézary syndrome, we found the cell cycle-regulating protein p16 to be absent in T cells. Immunohistochemical staining with p16-specific antibodies showed that the number of p16-expressing cells in cutaneous lesions decreases in late stages. The repression of p16 was not attributable to deletion or methylation of this gene; however, the Bmi-1 oncogene, a known suppressor of p16, was present in mycosis fungoides and Sézary syndrome cell lines and skin lesions. The absence of p16 correlated with the phosphorylation of the retinoblastoma protein on cyclin D/CDK4- or cyclin D/CDK6-specific sites. Ki-ras, which stimulates phosphorylation of retinoblastoma via cyclin-dependent kinases, was found in all tested cutaneous T-cell lymphoma samples; and its expression generally was stronger in advanced stages. Thus, cutaneous T-cell lymphoma cells show changes in oncogene and tumor suppressor gene expression that increase proliferation.

Acrally distributed dermatoses: Vascular dermatoses (purpura and vasculitis).

Purpuric lesions appear in acral distribution in a variety of conditions and often provide clues to the clinical diagnosis. Purpuric means "hemorrhagic"-that is, the lesions do not blanch from pressure. This review focuses on dermatoses that produce hemorrhagic lesions in acral distribution from the large groups of the vasculitic diseases and their mimics. Cutaneous small vessel vasculitis is confined to the skin, involves mainly postcapillary venules, and has the hallmark manifestation of palpable purpura. Henoch-Schönlein purpura is an immune complex-mediated systemic vasculitis of the small vessels with manifestations from the skin, joints, kidneys, and gastrointestinal system. Only cases where the immune complexes contain immunoglobulin A type are classified as Henoch-Schönlein purpura. Cryoglobulinemic vasculitis is induced by the deposition of cold-precipitated immune complexes in the small vessels. Urticarial vasculitis comprises a spectrum of conditions with the characteristic course of chronic urticaria, with wheals that persist longer than 24 hours, leave hyperpigmentation, and have leukocytoclastic vasculitis on histologic examination. Polyarteritis nodosa is a rare multisystem, segmental necrotizing vasculitis of mainly the medium-sized vessels. Pigmented purpuric dermatoses are chronic benign dermatoses characterized by petechiae, purpura, and increased skin pigmentation. The hallmark of pigmented purpuric dermatoses is their orange-brown, speckled, cayenne pepper-like discoloration.

An adaptive signaling network in melanoma inflammatory niches confers tolerance to MAPK signaling inhibition.

Mitogen-activated protein kinase (MAPK) pathway antagonists induce profound clinical responses in advanced cutaneous melanoma, but complete remissions are frustrated by the development of acquired resistance. Before resistance emerges, adaptive responses establish a mutation-independent drug tolerance. Antagonizing these adaptive responses could improve drug effects, thereby thwarting the emergence of acquired resistance. In this study, we reveal that inflammatory niches consisting of tumor-associated macrophages and fibroblasts contribute to treatment tolerance through a cytokine-signaling network that involves macrophage-derived IL-1ß and fibroblast-derived CXCR2 ligands. Fibroblasts require IL-1ß to produce CXCR2 ligands, and loss of host IL-1R signaling in vivo reduces melanoma growth. In tumors from patients on treatment, signaling from inflammatory niches is amplified in the presence of MAPK inhibitors. Signaling from inflammatory niches counteracts combined BRAF/MEK (MAPK/extracellular signal-regulated kinase kinase) inhibitor treatment, and consequently, inhibiting IL-1R or CXCR2 signaling in vivo enhanced the efficacy of MAPK inhibitors. We conclude that melanoma inflammatory niches adapt to and confer drug tolerance toward BRAF and MEK inhibitors early during treatment.

CD4+CD56+ hematodermic neoplasms bear a plasmacytoid dendritic cell phenotype.

CD4+CD56+ hematodermic neoplasms (HNs) with initial presentation in the skin are characterized by highly aggressive behavior and poor prognosis. Recent studies indicate that malignant cells, which are devoid of common T-, B-, NK-, and myeloid lineage markers, may be of plasmacytoid dendritic cell (pDC) origin. We undertook a study to assess the expression of several pDC-associated molecules on a series of 5 CD4+CD56+ HN cases. CD123 was expressed in all 5 cases, with some heterogeneity in individual cases. All but one case revealed fine membranous BDCA-2 staining of the dermal infiltrate. pDC-like phenotype of the malignant infiltrating cells was confirmed by costaining of BDCA-2+ cells with CD123 and CD4. MxA protein, representing the surrogate marker for lesional type I interferon activity, was expressed in 4 of 5 evaluated cases. Our findings further substantiate the putative pDC origin of CD4+CD56+ HNs.

Borrelial pseudolymphoma of the nose.

A 52-year-old Colombian woman, a patient with psoriasis, undergoing phototherapy with (ultraviolet B narrowband) UVBnb, presented with a symptomless solitary diffuse erythaematous plaque on her nose for 3 months. Initially, she was treated with pimecrolimus 1% cream for 8 weeks, which was then combined with metronidazole cream for 4 weeks, with the initial diagnosis of UV-triggered rosacea, without improvement. A punch biopsy was performed and the histology showed a pseudolymphomatous reaction. The diagnosis of nasal pseudolymphoma of borreliosis was confirmed with PCR. The lesion completely resolved following oral doxycycline therapy.

Clinical observation of panniculitis in two patients with BRAF-mutated metastatic melanoma treated with a combination of a BRAF inhibitor and a MEK inhibitor.

BACKGROUND: Treatment with selective BRAF or MEK inhibitors is frequently associated with cutaneous toxicities, including squamous cell carcinoma (SCC), papillomas and rash. These cutaneous adverse effects are typically observed at a lower incidence during combined BRAF and MEK inhibitor therapy. PATIENTS AND METHODS: Two male patients with stage IV metastatic BRAF-mutated melanoma were treated with a combination of a selective BRAF inhibitor and a selective MEK inhibitor (dabrafenib and trametinib, or encorafenib (LGX818) and binimetinib (MEK162)) within two different clinical trials. Ten and 150 days after treatment start respectively, the patients developed painful nodules on the legs. In addition, one patient developed symmetrical articulation pain and intermittent fever episodes. RESULTS: Based on the clinical and histological presentation, erythema nodosum-like panniculitis was diagnosed in both cases. No other aetiology could be found. After receiving topical or oral steroid treatment and anti-inflammatory analgesics, the painful nodular lesions disappeared several weeks later. In one case, a rebound of the painful nodules was observed when the combination treatment (dabrafenib and trametinib) was resumed after a 1-week unscheduled treatment interruption. CONCLUSIONS: Panniculitis has previously been described in association with BRAF inhibitor treatment, but not MEK inhibitor treatment. Combination treatment is usually associated with a lower incidence of cutaneous adverse events (AEs), as compared to monotherapy. Panniculitis was observed in two patients during combined BRAF and MEK inhibitor treatment. These cases illustrate the need for further research in a larger patient population to identify a possible link between combined BRAF and MEK inhibitor treatment and the incidence of panniculitis.

Clinicopathologic features of primary cutaneous melanoma: a single centre analysis of a Swiss regional population.

BACKGROUND: Melanoma is a common type of skin cancer with poor survival in advanced stages. Screening efforts aim to detect and tackle tumors at an early stage. However, regional population-based data at the time of initial diagnosis are sparse. OBJECTIVES: To analyse clinical and pathologic tumor characteristics in a Swiss population. MATERIALS AND METHODS: Melanoma samples diagnosed at a large Swiss academic department were evaluated for demographic, clinical and histopathologic data. RESULTS: We analysed a total of 254 melanoma samples. In situ tumors were more common in females than in males (70.6% vs. 29.4%; p = 0.0032). The acro-lentiginous subtype was more common in in situ compared to invasive tumors (14.7% vs. 5.5%; p = 0.0011). Invasive tumors showed a preference for male gender in patients beyond 60 years of age (p = 0.0080). The most frequent anatomic sites were the trunk in males and the legs in females. Regression was more common in males than in females (35.2% vs. 11.7%; p = 0.0001). Breslow's thickness correlated significantly with age but not with gender. Ulceration was common in tumors thicker than 2.01 mm (48.4%; p = 0.0001). Regression was frequently detected in melanomas thinner than 1.00 mm (29.3%; p = 0.0263). CONCLUSION: Screening efforts should target elderly patients. Skin examinations should include acral localisations and focus on the trunk in males and the lower extremities in females. Population-based analyses can help to fine-tune melanoma screening in defined regional populations.