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Objective: The efficacy of combined BRAF and MEK inhibition for BRAF V600-mutant melanoma in a broad patient population, including subgroups excluded from phase 3 trials, remains unanswered. This noninterventional study (DATUM-NIS) assessed the real-world efficacy, safety and tolerability of dabrafenib plus trametinib in Austrian patients with unresectable/metastatic melanoma., Methods: This multicenter, open-label, non-interventional, post-approval, observational study investigated the effectiveness of dabrafenib plus trametinib prescribed in day-to-day clinical practice to patients ( N  = 79) with BRAF V600-mutant unresectable/metastatic melanoma with M1c disease (American Joint Committee on Cancer staging manual version 7), ECOG > 1, and elevated serum lactate dehydrogenase (LDH). The primary endpoint was 6-, 12- and 18-month progression-free survival (PFS) rates. Secondary endpoints were median PFS, disease control rate and overall survival (OS)., Results: The 6-, 12- and 18-month PFS rates were 76%, 30.6% and 16.2%, respectively. Subgroup analysis showed a significant PFS benefit in the absence of lung metastasis. The median PFS and OS were 9.1 (95% CI, 7.1-10.3) months and 17.9 (95% CI, 12.7-27.8) months, respectively. The 12- and 24-month OS rates were 62.7% and 26.8%, respectively. Subgroup analyses showed significant OS benefits in the absence of bone or lung metastasis and the presence of other metastases (excluding bone, lung, brain, liver and lymph nodes). Furthermore, S100 and Eastern Cooperative Oncology Group performance status (ECOG PS) showed a significant impact on survival. No new safety signals were observed., Conclusion: Despite an unselected population of melanoma patients with higher M1c disease, ECOG PS > 1 and elevated LDH, this real-world study demonstrated comparable efficacy and safety with the pivotal phase 3 clinical trials for dabrafenib-trametinib., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Cancer patients infected with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) have an increased risk of mortality. Here, we investigated predictive factors for coronavirus disease 2019 (COVID-19) associated mortality in patients with neoplastic diseases treated throughout Austria., Methods: In this multicentric nationwide cohort study, data on patients with active or previous malignant diseases and SARS-CoV‑2 infections diagnosed between 13 March 2020 and 06 April 2021 were collected. Collected data included the stage of the malignant disease and outcome parameters 30 days after the diagnosis of SARS-CoV‑2 infection., Results: The cohort consisted of 230 individuals of which 75 (32.6%) patients were diagnosed with hematologic malignancies and 155 (67.4%) with solid tumors. At a median follow-up of 31 days after COVID-19 diagnosis, 38 (16.5%) patients had died due to COVID-19. Compared to survivors, patients who died were older (62.4 vs. 71.4 years, p < 0.001) and had a higher ECOG performance status (0.7 vs. 2.43, p < 0.001). Furthermore, higher neutrophil counts (64.9% vs. 73.8%, p = 0.03), lower lymphocyte counts (21.4% vs. 14%, p = 0.006) and lower albumin levels (32.5 g/l vs. 21.6 g/l, p < 0.001) were observed to be independent risk factors for adverse outcomes. No association between mortality and systemic antineoplastic therapy was found (p > 0.05). In 60.6% of the patients, therapy was postponed due to quarantine requirements or hospital admission., Conclusion: Mortality of Austrian cancer patients infected with SARS-CoV‑2 is comparable to that of other countries. Furthermore, risk factors associated with higher mortality were evident and similar to the general population. Treatment delays were frequently observed., (© 2022. The Author(s).)

Background and Objectives: We examined retrospectively whether the combination of standard dacarbazine (DTIC) and/or fotemustine chemotherapy and autologous peptide-loaded dendritic cell (DC) vaccination may improve survival of stage IV melanoma patients. Furthermore, a small cohort of long-term survivors was studied in more detail., Patients and Methods: Between 1998 and 2008, 41 patients were vaccinated at least three times with DCs while receiving chemotherapy and compared to all other 168 patients in our database who only received chemotherapy (1993-2008)., Results: Median life expectancy of patients receiving additional DC-vaccination was 18 months, compared to eleven months for patients under standard chemotherapy alone. In contrast to patients with other haplotypes, the HLA-A1/A1 subset of DC-treated patients showed significantly lower median survival (12 vs. 25 months). Autoantibodies were frequently detected in serum of both vaccinated and non-vaccinated patients, and there was no correlation between titers, loss or appearance of autoantibodies and survival. Additionally, phenotyping of DCs and PBMCs also did not reveal any conspicuous correlation with survival., Conclusions: Combining standard chemotherapy and DC vaccination appears superior to chemotherapy alone. The impact of HLA haplotypes on survival emphasizes the importance of a careful selection of patients with specific, well-defined HLA haplotypes for future vaccination trials using peptide-pulsed DCs, possibly combined with checkpoint inhibitors., (© 2020 The Authors. Journal der Deutschen Dermatologischen Gesellschaft published by John Wiley & Sons Ltd on behalf of Deutsche Dermatologische Gesellschaft.)

Cutaneous melanoma (CM) incidence is rising worldwide and is the primary cause of death from skin disease in the Western world. Personal risk factors linked to environmental ultraviolet radiation (UVR) are well-known etiological factors contributing to its development. Nevertheless, UVR can contribute to the development of CM in different patterns and to varying degrees. The present study aimed at investigating whether altitude of residence can contribute to the development of specific types of CM and/or influence its progression. To this aim, 306 formalin-fixed and paraffin-embedded (FFPE) tissues from primary CM diagnosed in different geographical areas were submitted to B-RAF proto-oncogene serine/threonine kinase (BRAF) and N-RAS proto-oncogene GTPase (NRAS) mutational status detection and mRNA and miRNA profiling by qPCR. Genes were chosen for their functions in specific processes, such as immune response ( CD2 , PDL1 , or CD274 ) and pigmentation ( MITF , TYRP1 , and TRPM1 ). Furthermore, four microRNAs, namely miR-150-5p , miR-155-5p , miR-204-5p , and miR-211-5p , were included in the profiling. Our results highlight differences in the gene expression profile of primary CM with respect to the geographical area and the altitude of residence. Melanoma-specific survival was influenced by the gene expression of mRNA and miRNAs and varied with the altitude of patients' residence. In detail, TYRP1 and miR-204-5p were highly expressed in patients living at higher altitudes, unlike miR-150-5p, miR-155-5p , and miR-211-5p . Since miRNAs are highly regulated by reactive oxygen species, it is possible that different regulatory mechanisms characterize CMs at different altitudes due to the different environment and UVR intensity.

In this case report, we describe a patient with an inoperable mucosal melanoma of the sinonasal cavity who achieved an ongoing complete response to combined immunotherapy with ipilimumab and nivolumab after initial pseudoprogression. Despite massive enlargement of the tumor 9 weeks after treatment initiation, we decided to continue with checkpoint inhibitor immunotherapy because of lacking potent therapeutic alternatives and the possibility of pseudoprogression. In the computed tomography scan 3 months later, the tumor was no longer detectable. To date, the patient is still in remission. However, she developed severe immune-related thrombocytopenia and neutropenia that are rarely encountered with checkpoint inhibitor immunotherapy. Thrombocytopenia did not respond to corticosteroids, but rapidly improved after the administration of single-dose intravenous immunoglobulin. This exceptional case highlights the effectiveness of combined immunotherapy with ipilimumab and nivolumab in mucosal melanoma, the phenomenon of pseudoprogression, as well as the rare event of immune-related hematological side effects.

Immunotherapy for metastatic melanoma offers great promise but, to date, only a subset of patients have responded. There is an urgent need to identify ways of allocating patients to the most beneficial therapy, to increase survival and decrease therapy-associated morbidity and costs. Blood-based biomarkers are of particular interest because of their straightforward implementation in routine clinical care. We sought to identify markers for dendritic cell (DC) vaccine-based immunotherapy against metastatic melanoma through gene expression analysis of peripheral blood mononuclear cells. A large-scale microarray analysis of 74 samples from two treatment centers, taken directly after the first round of DC vaccination, was performed. We found that phosphatidylethanolamine binding protein 1 ( PEBP1) /Raf Kinase inhibitory protein (RKIP) expression can be used to identify a significant proportion of patients who performed poorly after DC vaccination. This result was validated by q-PCR analysis on blood samples from a second cohort of 95 patients treated with DC vaccination in four different centers. We conclude that low PEBP1 expression correlates with poor overall survival after DC vaccination. Intriguingly, this was only the case for expression of PEBP1 after, but not prior to, DC vaccination. Moreover, the change in PEBP1 expression upon vaccination correlated well with survival. Further analyses revealed that PEBP1 expression positively correlated with genes involved in T cell responses but inversely correlated with genes associated with myeloid cells and aberrant inflammation including STAT3, NOTCH1 , and MAPK1 . Concordantly, PEBP1 inversely correlated with the myeloid/lymphoid-ratio and was suppressed in patients suffering from chronic inflammatory disease., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest

Purpose: To evaluate the outcome of patients with melanoma liver metastasis treated with stereotactic radiofrequency ablation (SRFA)., Material and Method: Following IRB approval, a retrospective evaluation of the treatment of 20 patients with 75 melanoma liver metastases was performed., Results: A median number of 2 lesions (range 1-14) per patient with a median size of 1.7 cm (range 0.5-14.5 cm) were treated. 67 lesions were <3 cm (89.3 %) and 8 lesions were >3 cm (10.7 %). Per patient a median of 1 ablation session was performed (range: 1-4) totaling 34 sessions. There were no procedure-related deaths and all major complications (n = 3) could be easily treated by pleural drainages. The primary and secondary success rates were 89.3 and 93.3 %, respectively. The overall local recurrence rate was 13.3 %. Four of ten local recurrences were re-treated successfully by SRFA. During follow-up, 9/20 patients developed extrahepatic metastatic disease and 10/20 had liver recurrence at any location. The median OS from the date of SRFA was 19.3 months, with an OS of 64, 41, and 17 % at 1, 3, and 5 years, with no significant difference for patients with cutaneous and ocular melanoma. The median DFS after SRFA for all 20 patients was 9.5 months, with 37, 9, and 0 % at 1, 3, and 5 years., Conclusions: Due to the high local curative potential and the promising long-term survival rates associated with minimal morbidity and mortality, radiofrequency ablation seems to be an attractive alternative to resection in patients with melanoma liver metastases.

In this retrospective pilot study, the DNA-methylation status of genes that have been demonstrated to be involved in melanoma carcinogenesis was analyzed in order to identify novel biomarkers for the risk assessment of melanoma patients. We analyzed DNA extracted from punch-biopsies from 68 formalin-fixed paraffin-embedded (FFPE) melanoma specimens. Using MethyLight PCR, we examined 20 genes in specimens from a training set comprising 36 melanoma patients. Selected candidate genes were validated in a test set using FFPE tissue samples from 32 melanoma patients. First, we identified the TNFRSF10D DNA-methylation status (TNFRSF10D methylated vs. unmethylated) as a prognostic marker for overall (p = 0.001) and for relapse-free survival (p = 0.008) in the training set. This finding was confirmed in the independent test set (n = 32; overall survival p = 0.041; relapse-free survival p = 0.012). In a multivariate Cox-regression analysis including all patients, the TNFRSF10D DNA-methylation status remained as the most significant prognostic parameter for overall and relapse-free survival (relative-risk (RR) of death, 4.6 (95% CI: 2.0-11.0; p < 0.001), RR of relapse, 7.2 (95% CI: 2.8-18.3; p < 0.001)). In this study, we demonstrate that TNFRSF10D DNA-methylation analysis of a small tissue-punch from archival FFPE melanoma tissue is a promising approach to provide prognostic information in patients with melanoma.

Multiple functional implications have been suggested for a limited number of chemokines and their cognate receptors in melanoma pathogenesis. The purpose of this study was to investigate the potential role of the chemokine receptors CXCR4, CCR7, CCR9, and CCR10 as prognostic markers in human primary cutaneous melanoma. Chemokine receptor expression was analyzed by immunohistochemistry in a total of 38 patients with cutaneous melanoma. Results were statistically correlated with melanoma features and clinical disease progression. No significant correlation between overexpression of CXCR4 or CCR9 and survival or prognosis was found. CCR7 overexpression was associated with significantly lower survival (0.005 log rank) and shorter time to progression (0.009 log rank)-similar to CCR10 overexpression (lower survival: 0.001 log rank, shorter time to progression: 0.002 log rank). In addition, CCR7 overexpression correlated with expression of metallothionein, while CCR10 seems to be associated with cerebral metastases. Two chemokine receptors permitting the identification of high-risk patients were identified: CCR7 and CCR10 overexpressions were found to be associated with a worse outcome of disease course independent of Breslow's tumor thickness and Clark level, thus representing possible additional prognostic markers.

Malignant melanoma is one of the most aggressive human neoplasms and its incidence is still increasing. Prognoses for melanoma patients are currently based on statistical parameters. For estimating the risk for a possible progression and for overall survival, Breslow tumour thickness and the invasion level (Clark level) are the most established markers for melanomas at the time of the primary diagnosis. In thicker melanomas (>1 mm) the additional information about the status of the sentinel lymph-node (SLN) might be helpful. Nevertheless new prognostic parameters are needed, that will allow us to formulate more precise prognoses for the individual cases. The metallo-thionein family is a class of intracellular low-molecular-weight, cysteine-rich proteins with a high affinity for heavy-metal ions. They are involved in many (patho-) physiological processes and presumably play an important role in the carcinogenesis. In the last decades overexpression of immunohistochemically labelled metallothioneins (MTs) on paraffin-embedded tissues turned out as a highly significant prognostic marker in different tumours. This review summarizes the results of those studies, in which MT-overexpression was able to show a very high significance for progression and survival in melanoma patients. In contrast to most other progression markers, MT-overexpression is independent from tumour-thickness, and is highly specific even in thin (low risk) melanoma patients. Nowadays, in high risk melanoma patients sentinel lymph-node (SLN-) biopsy is performed, a surgical technique with predictive value for progression, the benefit of this procedure for the individual overall survival still remains unclear. In a study comparing SLN and MT-overexpression the results corroborate the validity of MT-overexpression in primary melanoma as a useful additional prognostic marker, accuracy is comparable although to some degree supplementary to the results of SLN biopsy.

Objective: In this experimental study, the antineoplastic potential of orally administered rapamycin in human melanoma was evaluated and compared with dacarbazine (DTIC) as well as with the antineoplastic effect of the combination of both drugs., Methods: The substances were tested using 2 human melanoma cell lines, 518A2, which is highly susceptible to DTIC, and 607B, which is moderately susceptible. A human melanoma severe combined immunodeficiency mouse xenotransplantation model was used. After development of palpable tumors, mice received oral rapamycin or saline over 18 days. Additionally, from treatment day 4 to 8, mice were randomly chosen to receive either DTIC or saline treatment., Results: The oral rapamycin treatment (1.5, 7.5, 15 and 30 mg/kg body weight) had an antineoplastic effect, ranging from 35 to 78% tumor weight reduction compared with the saline group. In DTIC less sensitive 607B tumors, rapamycin treatment (15 and 30 mg/kg body weight) was superior to DTIC treatment (p < 0.05). DTIC monotreatment reduced tumor weight in 518A2 tumors by 85% on average, whereas in 607B xenografts, no significant tumor weight reduction was observed compared with the saline group (p > 0.05). The combination of rapamycin and DTIC was not superior to rapamycin monotreatment in any cell line., Conclusion: These data indicate that oral rapamycin exerts a relevant antineoplastic effect on human melanoma cells. This effect appeared to be more pronounced in DTIC less sensitive melanoma xenografts., (Copyright 2008 S. Karger AG, Basel.)

Background: Indoleamine (2,3)-dioxygenase (IDO) catalyses the initial, rate-limiting step in the degradation of the essential amino acid tryptophan. Via tryptophan deprivation, IDO activity suppresses T cell proliferation and differentiation and is thought to be a fundamental immune escape mechanism for tumor cells., Objective and Methods: To investigate the potential role of tryptophan degradation as a prognostic marker, serum tryptophan and kynurenine concentrations and the kynurenine-to-tryptophan ratio (kyn/trp) in 87 patients with malignant melanoma were compared to the course of the disease and to concentrations of the immune activation marker neopterin., Results: Compared to 49 healthy volunteers, the melanoma patients presented with lower tryptophan levels due to accelerated degradation. This was especially true for the subgroups of patients with distant metastases (p = 0.01), though not in patients with lymph node metastases or in patients who had not yet progressed. There existed a positive correlation between kyn/trp and neopterin concentrations (r(s) = 0.587, p <0.001). In patients who died due to dissemination of the tumor, median tryptophan concentrations were significantly decreased (p = 0.006) and kyn/trp (p = 0.03) and neopterin concentrations (p = 0.002) were higher compared to survivors. In addition, lower tryptophan concentrations as well as higher kyn/trp and neopterin concentrations predicted a shorter survival., Conclusion: Decreased serum tryptophan concentrations and elevated serum neopterin levels can be used as predictive markers for the future course in melanoma patients. Moreover, our data support previous speculations that a higher degree of IDO expression could play a crucial role for tumor progression.

There is consensus that an optimized cancer vaccine will have to induce not only CD8+ cytotoxic but also CD4+ T helper (Th) cells, particularly interferon (IFN)-gamma-producing, type 1 Th cells. The induction of strong, ex vivo detectable type 1 Th cell responses has not been reported to date. We demonstrate now that the subcutaneous injection of cryopreserved, mature, antigen-loaded, monocyte-derived dendritic cells (DCs) rapidly induces unequivocal Th1 responses (ex vivo detectable IFN-gamma-producing effectors as well as proliferating precursors) both to the control antigen KLH and to major histocompatibility complex (MHC) class II-restricted tumor peptides (melanoma-antigen [Mage]-3.DP4 and Mage-3.DR13) in the majority of 16 evaluable patients with metastatic melanoma. These Th1 cells recognized not only peptides, but also DCs loaded with Mage-3 protein, and in case of Mage-3DP4-specific Th1 cells IFN-gamma was released even after direct recognition of viable, Mage-3-expressing HLA-DP4+ melanoma cells. The capacity of DCs to rapidly induce Th1 cells should be valuable to evaluate whether Th1 cells are instrumental in targeting human cancer and chronic infections.

Variegate porphyria is a rare disease caused by a deficiency of protoporphyrinogen oxidase. In most cases, the clinical findings are a combination of systemic symptoms similar to those occurring in acute intermittent porphyria and cutaneous lesions indistinguishable from those of porphyria cutanea tarda. We report on a 24-year-old woman with variegate porphyria who, after intake of lynestrenol, developed typical cutaneous lesions but no viscero-neurological symptoms. The diagnosis was based on the characteristic urinary coproporphyrin and faecal protoporphyrin excretion patterns, and the specific peak of plasma fluorescence at 626 nm in spectrofluorometry. Biochemical analysis revealed that most of the family members, though free of clinical symptoms, excrete porphyrin metabolites in urine and stool similar to variegate porphyria, accompanied by a significant decrease of porphobilinogen deaminase activity of a range which is ordinarily found in patients with acute intermittent porphyria only (approximately 50%). These data first led to the assumption of two separate and independently inherited genetic defects, similar to the dual porphyria of Chester. Molecular analysis, however, revealed only a missense mutation of the protoporphyrinogen oxidase gene, but not of the porphobilinogen deaminase gene. Thus, in the family presented, porphobilinogen deaminase deficiency is likely to be a phenomenon secondary to the genetic defect of protoporphyrinogen oxidase.

Objective: To characterize the epidermal permeability barrier function of skin during exposure to ionizing radiation., Design: A prospective cohort study., Setting: University hospital medical center., Patients: Fifteen women receiving local radiation therapy (5000-6000 rad [50-60 Gy]) following breast-conserving surgery for breast cancer., Main Outcome Measures: Clinical symptoms and transepidermal water loss (TEWL)., Results: Epidermal permeability barrier function is impaired in patients who exhibit clinical signs of radiation dermatitis. The functional damage to the stratum corneum induced by ionizing radiation occurs with a delayed course, starting within a mean period of 11 days and reaching maximal values after a mean period of 27 days (range, 13-75 days). The onset of TEWL increase precedes the onset of radiation dermatitis and the maximal TEWL measurements precede the peak of skin changes. Patients with an early onset of TEWL increase show a longer duration of skin symptoms., Conclusions: Skin changes caused by radiation dermatitis are associated with an increase in TEWL. The barrier impairment is comparable to the changes observed with UV radiation exposure but exhibits an even more delayed course. Our results suggest that preservation of the epidermal permeability barrier function by topical treatment may ameliorate radiation dermatitis.

Acral melanoma may present clinically and histologically with atypical features causing a delay in proper diagnosis. The aim of the present study was to assess the frequency of a histological variant with clear cell changes. Clinical information, hematoxylin & eosin stained paraffin sections and immunohistochemical staining profiles were reviewed in 49 cases of acral melanoma. Twenty-one (43%) specimens contained tumor cells with clear cell changes in focal areas, whereas in 7 (14%) specimens clear cells were the major tumor constituting cells. The tumor thickness ranged from melanoma in situ to 14 mm. Immunohistochemistry demonstrated weak staining for S100 and HMB45 as well as strong positivity for Melan A and NK1C3. Recognition of clear cell features is important since differential diagnosis includes a variety of other clear cell malignancies, among them metastasis from renal cell carcinoma, clear cell sarcoma and hidradenocarcinoma.

Aims: The present series describes six cases of perineurioma, a rare and frequently unrecognized entity, including one case with an unusual plexiform growth pattern., Methods: Retrospective clinicopathologic study of six perineuriomas., Results: All lesions occurred on the upper extremities or shoulders of adults, five in females. Histologically, all six cases of perineurioma had been initially unrecognized or misdiagnosed as dermatofibroma, fibroma of tendon sheath, neurofibroma, schwannoma, or naevus, respectively. Scanning magnification revealed well circumscribed, dermal to subcutaneous lesions without capsule formation. Besides characteristic onion bulbs", i.e. concentric whorls of epithelioid to spindle-shaped cells, there was great variation of histomorphologic features: single nodules or plexiform architecture; a few to many concentric whorls; five to several dozens of cell layers in concentric whorls; high to low cellularity; round/oval to spindle-shaped/wavy cells/nuclei; delicate to prominent collagen; variable mucin, sclerosis, and/or intralesional clefts. Immunohistochemically, all lesions were consistently positive for EMA, ultrastructurally (1 case) with evidence of perineurial differentiation such as slender and elongated, bipolar cytoplasmic processes with discontinuous basal lamina, prominent pinocytosis and desmosome-like junctions., Conclusion: Our series documents that cutaneous and subcutaneous perineurioma is frequently unrecognized or misinterpreted and may occasionally show a plexiform growth pattern. The differential diagnosis of plexiform variants includes a variety of plexiform lesions such as naevi, neurofibroma, schwannoma, etc. Historically, similar plexiform lesions seem to have been published as nerve sheath myxoma/neurothekeoma, Pacinian neurofibroma or perineurial myxoma. This terminology is imprecise and confusing and, thus, should be avoided in favour of the correct term of perineurioma.

Papular atrichia is an autosomal recessive disorder characterized clinically by the occurrence of universal congenital alopecia and disseminated papular lesions. Recently, mutations in the human hairless (HR) gene have been reported in Irish and Arab Palestinian families with papular atrichia. We have studied two further kindreds with this clinical phenotype from other ethnic backgrounds. For mutation detection the complete coding region as well as exon-intron boundaries of the HR gene were sequenced. The first family is a Mexican family with clinically typical papular atrichia. Sequencing identified a homozygous deletion of 4 bp in exon 7 (2001delCCAG) leading to a premature stop codon in exon 8. The second family is a South Tyrolian family with affected individuals showing papular atrichia and retardation of bone age during childhood. All affected individuals were identified as homozygous for an A-->G transition at nucleotide position 2909 (exon 14) leading to an amino acid change of asparagine to serine in codon 970 (Asn970Ser). These data provide further evidence for the involvement of hairless mutations in papular atrichia. In addition, these findings suggest that the hairless protein is not only involved in hair development but also in the process of ossification during development.

An important property of dendritic cells (DC), which contributes crucially to their strong immunogenic function, is their capacity to migrate from sites of antigen capture to the draining lymphoid organs. Here we studied in detail the migratory pathway and the differentiation of DC during migration in a skin organ culture model and, for comparison, in the conventional contact hypersensitivity system. We report several observations on the capacity of cutaneous DC to migrate in mouse ear skin. (i) Upon application of contact allergens in vivo the density of Langerhans cells in epidermal sheets decreased, as determined by immunostaining for major histocompatibility complex class II, ADPase, F4/80, CD11b, CD32, NLDC-145/DEC-205, and the cytoskeleton protein vimentin. Evaluation was performed by computer assisted morphometry. (ii) Chemically related nonsensitizing or tolerizing compounds left the density of Langerhans cells unchanged. (iii) Immunohistochemical double-staining of dermal sheets from skin organ cultures for major histocompatibility complex class II and CD54 excluded blood vessels as a cutaneous pathway of DC migration. (iv) Electron microscopy of organ cultures revealed dermal accumulations of DC (including Birbeck granule containing Langerhans cells) within typical lymphatic vessels. (v) Populations of migrating DC in organ cultures upregulated markers of maturity (the antigen recognized by monoclonal antibody 2A1, CD86), but retained indicators of immaturity (invariant chain, residual antigen processing function). These data provide additional evidence that during both the induction of contact hypersensitivity and in skin organ culture, Langerhans cells physically leave the epidermis. Both Langerhans cells and dermal DC enter lymphatic vessels. DC mature while they migrate through the skin.

We report five cases of plexiform fibrohistiocytic tumors, three classic subcutaneous lesions and two dermal ones. Both variants had similar profiles and were clinically indistinguishable. The lesions affected the trunk more than the upper extremities and were found in children and young adults (18.4 +/- 12.8 years). They showed a marked female predominance (4:1, including both dermal variants). Clinically, they were skin-colored, hard nodules of 1-2-cm diameter that resulted in such differential diagnoses as fibroma, histiocytoma, pilomatricoma, or cyst. Interestingly, one subcutaneous case with a painful "worms in the sack" presentation was thought to represent a plexiform neurofibroma. Histology revealed well-circumscribed dermal or subcutaneous plexiform lesions with a characteristic biphasic appearance. Most of the tumor bulk consisted of spindle-shaped to stellate myofibroblasts with a variable admixture of collagen or loosening of stroma. In the center of the plexiform strands and nodules, a few osteoclast-like giant cells as well as epithelioid mononuclear cells (< 10%) were found. Myofibroblasts were positive with HHF35 and for smooth muscle actin in three of five cases. Osteoclast-like giant cells were positive with KP1 in all five cases. Both types of cells stained with the macrophage marker Ki-M1p. A broad panel of other markers was negative. This series expands the spectrum of plexiform fibrohistiocytic tumor, but it also broadens the differential diagnosis of (dermal) plexiform lesions, which at present includes spindle cell nevi, schwannomas, neurofibromas, granular cell tumors, nerve sheath myxomas (neurothekeomas), spindle cell lipomas, and tufted angiomas.