KIT mutations and CD117 overexpression are markers of better progression-free survival in vulvar melanomas.

BACKGROUND: Few studies have addressed prognostic markers and none has correlated molecular status and prognosis in vulvar melanomas. OBJECTIVES: To evaluate the clinicopathological features of 95 cases of vulvar melanoma. METHODS: p53, CD117, Ki-67, neurofibromin, brafv600e and nrasq61r immunostains, and molecular analyses by either targeted next-generation or direct sequencing, were performed on available archival materials. RESULTS: Molecular testing detected mutations in KIT (44%), BRAF (25%), NF1 (22%), TP53 (17%), NRAS (9%) and TERT promoter (9%). Co-mutation of KIT and NF1 and of KIT and NRAS were identified in two and one cases, respectively. KIT mutations were significantly associated with better progression-free survival in univariate analyses. In multivariate analyses CD117 expression was significantly associated with better progression-free survival. Tumour thickness was significantly associated with worse progression-free and overall survival, and perineural invasion significantly correlated with reduced melanoma-specific survival and reduced overall survival. Cases were from multiple centres and only a subset of samples was available for molecular testing. CONCLUSIONS: KIT mutations and CD117 overexpression are markers of better progression-free survival. In addition to its prognostic value, molecular testing may identify cases that might respond to targeted agents or immunotherapeutic approaches.

Eruptive cutaneous squamous cell carcinoma and psoriasis: response to cetuximab.

Cutaneous squamous cell carcinomas (CSCCs) comprise 20-30% of nonmelanoma skin cancers (NMSCs), and continue to increase in incidence. We report a case of a patient with severe psoriasis who had recurrent and eruptive CSCCs on her leg, which were successfully treated with cetuximab and radiotherapy. The patient had successful long-term clearance of her skin tumours, with the additional finding of resolution of psoriasis while on cetuximab therapy.

Use of modifying phrases in surgical pathology reports: is there a different understanding between pathologists and treating physicians?

When not all the histopathologic and clinical features necessary for a pathology diagnosis are present in a particular specimen, pathologists may use modifying phrases to convey various degrees of certainty, e.g., "consistent with…" and "suggestive of…." However, it is unclear whether pathologists use such phrases consistently or whether treating physicians fully understand their intended meaning. A questionnaire concerning six common modifying phrases ("consistent with, suggestive of, suspicious for, highly consistent with, highly suggestive of, some features of") was sent to all physicians from a single institution who either issued or routinely received surgical pathology reports. Physicians were asked to rank their understanding of each phrase on a printed scale between 1 ("no evidence of") and 10 ("diagnostic of"). One hundred sixty physicians (74.3%) responded. Despite wide variation, there was a hierarchy (from more to less diagnostic): highly consistent > highly suspicious > consistent > suspicious > suggestive > some features (p < 1 × 10-7). There were no significant differences between pathologists and treating physicians (p = 0.72) or attendings and residents (p = 0.9). Pathologists and treating physicians share an overall common understanding of their hierarchical relationship, albeit with wide ranges. Based upon our results, we propose to use only three qualifying phrases to convey the degree of certainty for a particular diagnosis: "suggestive of" (> 25 ≤ 50% certainty), "suspicious for" (> 50 ≤ 75%), and "consistent with" (> 75%). The phrase "no evidence of" should probably be used only when there is ≤ 5% confidence in a diagnosis, and conversely, "diagnostic of" should probably be used only when there is ≥ 95% confidence in a diagnosis.

Rhodamine dyes as potential agents for photochemotherapy of cancer in human bladder carcinoma cells.

The phototoxicity in vitro of rhodamine 123 and tetrabromo rhodamine 123 (TBR) was compared, in order to assess their photochemotherapeutic potential. Exposure to 514.5-nm radiation from an argon ion laser caused phototoxicity in MGH-U1 bladder carcinoma cells previously treated with either dye at 10 microM for 30 min. As assessed by colony formation and cellular morphology, TBR was markedly more phototoxic than rhodamine 123, reflecting increased intersystem crossing of TBR to the triplet manifold via spin-orbital coupling induced by the heavy bromine atoms. Photoreactions of TBR very efficiently generated singlet oxygen (1O2) in solution; furthermore, irradiation of TBR-treated cells was significantly more toxic when performed in the presence of deuterium oxide, an enhancer of damage caused by 1O2. Retention of fluorescence in TBR-treated cells was enhanced by irradiation, indicating that a stable photoproduct may be formed in reaction with cellular components.

Mechanism of photosensitization by microsphere-bound chlorin e6 in human bladder carcinoma cells.

Photodynamic therapy is an experimental method of cancer treatment in which a photosensitizer is administered and subsequently the tumor is irradiated with light. Due to problems of prolonged skin phototoxicity with hematoporphyrin derivative, new photosensitizers and methods of localization are being sought. The goal of this study was to compare the photosensitizer chlorin e6 (Ce6) free and bound to 1-micron-diameter microspheres (MS) for phototoxicity, uptake and efflux characteristics, phagocytosis rates in malignant and benign cells, and effects of NaN3, D2O, and buthionine sulfoximine on phototoxic efficacy. Incubation of MGH-U1 human bladder carcinoma cells with Ce6-MS (0.43 microM Ce6-equivalent; 18 h) and subsequent irradiation using an argon laser-pumped dye laser at a radiant exposure of 20 J/cm2 caused 100% cell death 24 h after irradiation. In contrast, MGH-U1 cells incubated with free Ce6 (0.43 microM; 18 h) remained 100% viable 24 h after irradiation at a radiant exposure of up to 50 J/cm2. The presence of D2O during irradiation increased the phototoxicity to MGH-U1 cells, whereas the presence of NaN3 decreased it; these data support an important role for 1O2. Irradiation of MGH-U1 cells in the presence of the glutathione depleter buthionine sulfoximine also increased the phototoxicity, demonstrating a role for intracellular glutathione and possibly free radical intermediates. The cellular uptake of Ce6 was approximately 50 times lower than that of Ce6-MS at equivalent incubation concentrations. Efflux experiments showed that the phototoxicity of Ce6-MS was reduced by 40% for a 5-h washout time as compared to no washout time. In contrast, for free Ce6, the decrease was 95.3% under identical conditions. Because the total intracellular concentration of Ce6-MS after an efflux time of 5 h was only slightly changed, the decreased phototoxicity is attributed to an altered intracellular localization. Confocal laser scanning fluorescence microscopy data appear consistent with this hypothesis although they are not conclusive. The observed patterns were different at 0 and 5 h. Comparison of the phagocytosis rates of Ce6-MS by carcinoma and benign cells showed that on average 20 MS/cell were phagocytosed by MGH-U1 compared with 2.5 and 8.3 in the benign human fibroblasts and keratinocytes, respectively. After incubation with Ce6-MS (0.1 microM; 18 h) and irradiation at 10 J/cm2 the surviving fraction of MGH-U1 cells was 76.3 +/- 0.95% (mean +/- SE) and 40 +/- 3.49% for fibroblasts. In contrast, for keratinocytes the surviving fraction was 93.5 +/- 0.83%.(ABSTRACT TRUNCATED AT 400 WORDS)

Rhodamine 123 phototoxicity in laser-irradiated MGH-U1 human carcinoma cells studied in vitro by electron microscopy and confocal laser scanning microscopy.

Rhodamine 123 (R123) is a permeant, cationic, fluorescent dye that localizes preferentially within mitochondria of living carcinoma cells. MGH-U1 human bladder carcinoma cells incubated in vitro with 10 microM R123 for 30 min and then irradiated at 514.5 nm with an argon ion laser underwent selective, phototoxic injury to mitochondria. Ultrastructurally, treatment with R123 plus irradiation with 10 J/cm2 caused selective, progressive mitochondrial alterations consisting of disruption of cristae, vacuolization, swelling, increasing numbers of ring-shaped and angulated mitochondria at 4 to 8 h after irradiation, and obliteration of many mitochondria at 24 to 48 h. Confocal laser scanning microscopy after treatment with R123 plus irradiation with 10 to 30 J/cm2 demonstrated altered uptake and localization of subsequently administered R123, accompanied by striking mitochondrial fragmentation. Irradiation caused a dose-dependent depletion of extractable R123, due to a photosensitized efflux that began immediately and progressed by 4 h after irradiation with 10 to 30 J/cm2; further uptake after reincubation in the presence of R123 was also quantitatively impaired in cells previously irradiated with 30 J/cm2.

Experimental photoimmunotherapy of hepatic metastases of colorectal cancer with a 17.1A chlorin(e6) immunoconjugate.

Photoimmunotherapy (using a monoclonal antibody-targeted photosensitizer and red light) may be a strategy to overcome the limitations inherent in photodynamic therapy of liver tumors. The aims of this study were (a) to test the efficacy of selective treatment of hepatic metastases of colorectal cancer in an orthotopic murine xenograft using the murine monoclonal antibody 17.1A conjugated to the photosensitizer chlorin(e6), and (b) to compare the tumor response after the same light dose was delivered at two different fluence rates. Based on previous biodistribution studies that had shown that the photoimmunoconjugate with a polyanionic charge had both a higher absolute tumor chlorin(e6) content and a greater tumor:normal liver ratio than those obtained with a photoimmunoconjugate bearing a polycationic charge, mice were treated 3 h after i.v. injection of the polyanionic 17.1A chlorin(e6) conjugate or unconjugated photosensitizer. Red light was delivered into the liver tumor by an interstitial fiber, and tumor response end points were total tumor weight in the short term and survival in the long term. There was a highly significant reduction (<20% of controls; P = 0.0035) in the weight of the tumors in the mice treated with photoimmunotherapy, and the median survival increased from 62.5 to 102 days (P = 0.015). Photodynamic therapy with free chlorin(e6) produced a smaller decrease in tumor weight and a smaller extension of survival, neither of which were statistically significant. A comparison of photoimmunotherapy with 10 J of light delivered at 30 or 300 mW showed that the higher fluence rate prolonged survival significantly more than the lower fluence rate. This may have been because the high fluence rate gave a contribution of laser-induced hyperthermia to the photodamage. Correlation studies showed that the amount of normal liver remaining at necropsy correlated best with survival. Photoimmunotherapy shows efficacy in destroying liver tumors, and future studies should maximize selectivity to minimize the destruction of normal liver.

Loss of expression of the p16/cyclin-dependent kinase inhibitor 2 tumor suppressor gene in melanocytic lesions correlates with invasive stage of tumor progression.

Sporadic and familial malignant melanoma susceptibility has been linked to defects in the chromosomal region 9p21. Recently, a putative 9p21 tumor suppressor gene, the cyclin dependent kinase inhibitor 2 (CDKN2) or p16 gene, has been shown to be deleted, mutated, or rearranged in a high percentage of sporadic melanoma cell lines, as well as mutated in the germline of a proportion of familial melanoma patients. CDKN2 encodes a M(r) 16,000 protein (p16) that plays a key role in cell cycle control by binding to the cyclin-dependent kinase 4 enzyme and inhibiting its ability to phosphorylate critical substrates necessary for transition past the G1 phase of the cell cycle. Thus, mutations or deletions of the CDKN2 gene could result in abnormal proliferation via defective cell cycle control. The correlation of 9p21 cytogenetic and molecular alterations with the clinical stages of melanoma progression suggests that dysfunction of a gene within this chromosomal region is critical to the evolution of melanoma. However, it remains unclear whether this gene is the CDKN2 gene. If so, then loss of p16 is potentially an initiating or early event in melanoma progression. To address the issues of what is the potential involvement of the CDKN2 gene in sporadic melanoma and precisely when during the clinically evident stages of melanoma progression defects in CDKN2 occur, we have evaluated by immunohistochemistry the expression of p16 protein in 103 melanocytic lesions representing all stages in the progression of melanoma. Our results suggest that loss of p16 protein expression is (a) not necessary for tumor initiation in malignant melanoma because all melanomas in situ and the majority of primary invasive melanomas retain expression of this protein; and (b) potentially more related to invasiveness or the ability to metastasize, because 52% of primary invasive tumors and 72% of metastatic lesions show partial or complete loss of expression of p16.

Dual role of SIRT1 in UVB-induced skin tumorigenesis.

The protein deacetylase SIRT1 regulates various pathways in metabolism, aging and cancer. However, the role of SIRT1 in skin cancer remains unclear. Here, using mice with targeted deletions of SIRT1 in their epidermis in both resistant B6 and sensitive SKH1 hairless backgrounds, we show that the role of SIRT1 in skin cancer development induced by ultraviolet B (UVB) radiation is dependent on its gene dose. Keratinocyte-specific heterozygous deletion of SIRT1 promotes UVB-induced skin tumorigenesis, whereas homozygous deletion of SIRT1 suppresses skin tumor development but sensitizes the B6 mice to chronic solar injury. In mouse skin, SIRT1 is haploinsufficient for UVB-induced DNA damage repair and expression of xeroderma pigmentosum C (XPC), a protein critical for repairing UVB-induced DNA damage. As compared with normal human skin, downregulation of SIRT1 is in parallel with downregulation of XPC in human cutaneous squamous cell carcinoma at both the protein and mRNA levels. In contrast, homozygous SIRT1 deletion in mouse skin augments p53 acetylation and expression of its transcriptional target Noxa, and sensitizes the epidermis to UVB-induced apoptosis in vivo, while heterozygous SIRT1 deletion has no such effect. The gene dosage-dependent function of SIRT1 in DNA repair and cell survival is consistent with the dual roles of SIRT1 in UVB-induced skin tumorigenesis. Our results reveal the gene dosage-dependent in vivo functions of SIRT1 in skin tumorigenesis and may shed light on the role of SIRT1 in epithelial cancer induced by DNA damage.

Mitochondrial phototoxicity sensitized by doxycycline in cultured human carcinoma cells.

Cultured MGH-U1 (human urinary bladder carcinoma) cells were treated with doxycycline (DOTC) and long-wave UV radiation (UVA). At UVA doses of 1 J/cm2 and above, the cells showed mitochondrial damage, reflected by altered localization of the fluorescent probe rhodamine-123, and striking vacuolization of the cytoplasm. Cell membrane integrity, as monitored by exclusion of ethidium bromide, was maintained for several hours after mitochondrial damage was evident. These changes were potentiated by irradiation in the presence of deuterium oxide, and diminished by irradiation in the presence of sodium azide. Addition of catalase, superoxide dismutase, or mannitol did not alter the damage threshold. These data indicate that the mitochondrion is an earlier target of DOTC photosensitization than the cell membrane. The critical photochemistry appears to involve singlet oxygen.

The SCF/KIT pathway plays a critical role in the control of normal human melanocyte homeostasis.

During development, the interaction of stem cell factor (SCF) with its receptor, KIT, is critical for the survival of melanocytes. Limited in vivo human studies have suggested a possible activating role of SCF on adult human melanocytes. In order to study the impact of this pathway on normal melanocyte homeostasis, human skin xenografts were treated with serial injections of recombinant human SCF or a KIT-inhibitory antibody (K44.2). On histologic evaluation, SCF injection increased, whereas KIT inhibition decreased the number, size, and dendricity of melanocytes. Immunohistochemical expression of melanocyte differentiation antigens, including tyrosinase-related-protein-1 and gp100/pmel17, was markedly increased by treatment with SCF, and decreased by K44.2 treatment. The number of Ki67-positive melanocytes was increased in the SCF-treated tissue, suggesting a direct proliferative effect of SCF; conversely, treatment with K44.2 resulted in melanocyte loss, which did not appear reversible with prolonged treatment. These findings demonstrate that the SCF/KIT pathway remains critical in adult human skin, and that pharmacologic modulation of this single pathway can control cutaneous melanocyte homeostasis.

Phototoxicity of lumidoxycycline.

Doxycycline (DOTC) is a photosensitizing drug whose mechanism of phototoxicity is complicated by the large variety of stable photoproducts formed. To assess the role of a DOTC photoproduct, lumidoxycycline (LuDOTC), in the photosensitization mechanism of DOTC, MGH-U1 human bladder carcinoma cells were treated in vitro with either DOTC or LuDOTC, and irradiated with the 351-nm emission of an argon-ion laser. Both DOTC and LuDOTC were phototoxic and caused radiant-exposure-dependent inhibition of cellular incorporation of tritiated thymidine. On an absorbed-photon basis, DOTC was about five times as phototoxic as LuDOTC. Cellular uptake of DOTC was about five times as great as that of LuDOTC. Epifluorescence microscopy showed localization of LuDOTC predominantly within cellular membranes, particularly of mitochondria, as well as a low level of LuDOTC fluorescence diffusely within the cytoplasm. Epifluorescence microscopy of cells labeled with the mitochondrial probe, rhodamine 123, showed mitochondrial fragmentation and altered mitochondrial membrane integrity after LuDOTC photosensitization; these effects depended on radiant exposure and were partially reversible by 24 h after irradiation. For both DOTC and LuDOTC, phototoxicity was increased by irradiation in the presence of deuterium oxide and decreased in the presence of sodium azide, effects consistent with an important mechanistic role for singlet oxygen, O2(1 delta g), in the injury. In solution, LuDOTC and DOTC had similar quantum yields for generation of O2(1 delta g) as measured by time-resolved spectroscopy and by O2(1 delta g) trapping. LuDOTC was photostable in solution, but DOTC underwent significant photodegradation. These data demonstrate that DOTC photo-products such as LuDOTC have significant photobiologic activity and may play an important role in the phototoxicity mechanism of DOTC.

KIT expression reveals a population of precursor melanocytes in human skin.

Human skin is believed to harbor a reservoir population of precursor melanocytes. It has been difficult to identify these putative cells experimentally, because they lack phenotypic features that define mature melanocytes. We have evaluated expression of the KIT tyrosine kinase receptor, which is critical for melanocyte development, as a possible marker of these cells. Sections of human skin were evaluated with single- and double-immunolabeling techniques. KIT-reactive dendritic cells were identified in the basal layer of the epithelia and were most numerous in the follicular infundibula and the rete ridges. These cells were located on the epithelial side of the basement membrane and lacked expression of cytokeratin and mast cell tryptase. The location of the KIT-reactive cells was distinctly different from that of Langerhans cells (identified with anti-CD1a) or Merkel cells (identified with CAM 5.2). Within the epidermis and upper follicular infundibulum the majority of the KIT-reactive dendritic cells also coexpressed TRP-1, a marker present in differentiated melanocytes. In the deeper follicular regions, the coexpression of TRP-1 in the KIT-reactive cells was absent. Throughout the epidermis and follicle, however, the KIT-reactive cells coexpressed BCL-2, a marker known to be increased in melanocytes. Thus, KIT expression reveals a population of intraepithelial cells that have immunophenotypic characteristics of mature melanocytes within the upper epithelial regions, but lack the differentiated melanocytic phenotype within the deeper follicular regions. We propose that these KIT(+), BCL-2(+), and TRP-1(-) cells constitute a precursor melanocyte reservoir of human skin.

Indeterminate fibrohistiocytic lesions of the skin: is there a spectrum between dermatofibroma and dermatofibrosarcoma protuberans?

Routine histology and immunohistochemistry can usually distinguish dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP). DF generally expresses factor XIIIa whereas DFSP generally expresses CD34. The authors report 10 cutaneous fibrohistiocytic lesions combining clinical, histologic, and immunohistochemical features of both DF and DFSP. The lesions had an average size of 1.2 cm (range, 0.4-2.7 cm), and occurred on the trunk (n = 6), extremities (n = 3), and face (n = 1) of four men and six women (average age, 30.6 yrs; age range, 15-50 yrs). Eight lesions exhibited acanthosis and densely cellular fascicles with focal storiform areas. All had keloidal collagen, infiltrated the subcutis in a honeycomb pattern, and had low mitotic counts (0 to 4 mitoses per square millimeter). All were diffusely immunoreactive for factor XIIIa (30%-60% of the neoplastic cells) as well as CD34 (20%-70%). This series raises the possibility of a biologic spectrum between DF and DFSP; however, double-immunolabeling studies showed no notable coexpression of factor XIIIa and CD34 by individual cells, suggesting coexistence of two different cellular populations. After an average follow up of 22.3 months (range, 10-46 mos) in six cases, a single recurrence was documented. The ambiguous histologic features and the potential for local recurrence suggest that performing a complete excision may be prudent in these diagnostically indeterminate lesions.

Malignant melanoma with paradoxical maturation.

Typically, melanocytic nevi "mature" (i.e., exhibit a morphologic shift to smaller or spindle cells with progressive depth in the dermis). In contrast, most malignant melanomas (conventional MMs) lack maturation, and are composed of large pleomorphic cells throughout. The authors describe a series of melanomas with paradoxical maturation mimicking the pattern of nevi. Seventeen primary invasive melanomas with paradoxical maturation (IMPs), two epidermotropic metastatic melanomas with maturation (EMMMs), 13 compound nevi (CN), and 14 conventional MMs without apparent maturation were analyzed by histologic, cytomorphometric, and immunohistochemical techniques. With increasing dermal depth, both CN and IMPs had smaller nuclear and cellular areas, and decreased expression of Ki-67, glycoprotein (gp)100 (with HMB-45), and tyrosinase. IMPs had significant differences from conventional MMs; namely, smaller nuclear and cytoplasmic areas (deep), and decreased expression of Ki-67 (superficial and deep), gp100 (deep), and tyrosinase (deep). IMPs also had notable differences from CN: namely, larger nuclear and cellular areas, more confluence, more mitotic figures, increased Ki-67 and gp100 expression in both the superficial and deep portions, and more melanin (deep). The two EMMMs exhibited histologic and immunohistochemical features similar to the primary IMPs. IMP, because of its mimicry of nevus, can present a diagnostic hazard. The authors propose histologic, morphometric, and immunohistochemical criteria that facilitate recognition and accurate diagnosis of this unusual variant of melanoma.

Desmoplastic (sclerotic) nevus: an underrecognized entity that resembles dermatofibroma and desmoplastic melanoma.

Desmoplastic (sclerotic) nevus, a benign melanocytic neoplasm characterized by predominantly spindle-shaped nevus cells within a fibrotic stroma, can be confused with fibrous lesions and other melanocytic proliferations, including desmoplastic melanoma. We compared the histologic and immunohistochemical features of 16 desmoplastic nevi, nine desmoplastic melanomas, four hypopigmented blue nevi, and six dermatofibromas. The similarities between desmoplastic nevi and dermatofibromas included epidermal hyperplasia (12 of 16), presence of keloidal collagen (15 of 16), hypercellularity (16 of 16), and increased numbers of factor XIIIa-positive dendritic cells (12 of 12). The absence of adnexal induction (0 of 16), the rarity of lesions with multinucleated cells (3 of 16) or epidermal hyperpigmentation (2 of 16), and the presence of S-100 immunoreactivity (16 of 16) and melanocytic proliferation (9 of 16) helped differentiate desmoplastic nevi from dermatofibromas. The similarities between desmoplastic nevi and desmoplastic melanomas included the presence of atypical cells (16 of 16) and HMB-45 expression in the superficial portion of the lesions (11 of 16). The infrequent location on the head or neck (1 of 16), the absence of mitotic figures (0 of 16), a significantly lower number of Ki-67-reactive cells, and a decrease in HMB-45 expression in the deep area of the lesions (8 of 11) helped distinguish desmoplastic nevi from desmoplastic melanoma. Desmoplastic nevi had overlapping features with hypopigmented blue nevi, but features tending to favor the latter included a predominance of ovoid nuclei, higher numbers of atypical cells, and homogeneous staining with HMB-45. We conclude that a combination of histologic and immunohistochemical criteria facilitates the reliable diagnosis of desmoplastic nevus from its simulators.

Correlating architectural disorder and cytologic atypia in Clark (dysplastic) melanocytic nevi.

Histological architecture is very important in the pathological diagnosis of Clark (also known as atypical or dysplastic) melanocytic nevi. However, few studies have attempted to quantify architectural features or to correlate them directly with cytology. In 166 consecutive Clark nevi, the presence or absence of the following features in the intraepidermal or junctional component was recorded: (1) Architecture: circumscription, symmetry, cohesiveness of nests, suprabasal melanocytes, confluence, and single-cell proliferation; (2) Cytology of melanocytes: round/euchromatic nuclei, nuclear enlargement, cell enlargement, and prominent nucleoli. Each criterion was given a value of 0 or 1, and a summation score was obtained for both architecture and cytology in each case. The chi-square test was used to determine the significance of relationships among these parameters. The degrees of architectural disorder and of cytologic atypia were positively correlated (P = .026). Scores for both parameters were distributed over a wide range of values and were concentrated toward the low-middle portion of the spectrum. Several particular architectural and cytologic variables showed significant interdependence. Clark nevi exhibit a broad spectrum of architectural disorder and cytologic atypia, which, according to our data, generally are closely related features. Because some cases displayed a relatively high score for one parameter but a low score for the other, quantification of both parameters permits a more complete histopathologic evaluation of these lesions and may provide additional information for their clinical management.

Increased incidence of trisomy 8 in acute myeloid leukemia with skin infiltration (leukemia cutis).

Anecdotal literature reports and the authors' own observations suggest an association between chromosome 8 aneuploidy and leukemia cutis. The authors investigated this potential association by using fluorescence in situ hybridization (FISH) directly on skin infiltrates in a series of 11 patients with acute monocytic leukemia (AML). Seven of the 11 patients were aneuploid for chromosome 8 by FISH which was confirmed by dual color hybridization. Six of these seven patients were AML-M4 or M5 and one was M1. The majority of the cases with leukemia cutis expressed CD4 (90% of cases), CD14 (60%), and/or CD56 (50%) in bone marrow leukemic cells. The data show the utility of examination of skin infiltrates by FISH for the detection of trisomy 8 in leukemia cutis. They also suggest the importance of trisomy 8 as a factor in predisposition to skin infiltration in AML.

Neutrophilic spongiosis in pemphigus.

BACKGROUND: Acantholysis is the histologic hallmark in the diagnosis of all forms of pemphigus. However, biopsy specimens of early lesions may lack acantholysis and show only eosinophils in the epidermis in areas of spongiosis (eosinophilic spongiosis). We report two cases of pemphigus foliaceus and two cases of unclassified pemphigus (foliaceus vs vulgaris) in which neutrophilic spongiosis was the prominent histologic finding. OBSERVATIONS: Four patients developed blistering skin disorders that spared the mucous membranes. Skin biopsy specimens in all four patients showed striking infiltration of neutrophils into the epidermis. Acantholysis was focal and was absent in some sections. Direct immunofluorescence demonstrated intercellular deposition of IgG and C3 within the epidermis in all cases. There was no IgA deposition. Gram's stains were negative for bacteria in three cases and revealed Gram-positive cocci overlying an eroded area in one case. However, the neutrophilic spongiosis in this case extended well beyond the area of impetiginization. CONCLUSIONS: The histologic differential diagnosis of neutrophils in the epidermis includes pustular psoriasis, subcorneal pustular dermatosis, intraepidermal neutrophilic IgA dermatosis, superficial IgA pemphigus, toxic shock syndrome, Sweet's syndrome, and superficial fungal and bacterial infections. We conclude that pemphigus be added to this differential diagnosis and recommend direct immunofluorescence when neutrophilic spongiosis is observed.

Reticular erythematous mucinosis syndrome. Report of two cases.

Two female patients had eruptions with the morphologic and histologic features of reticular erythematous mucinosis syndrome. However, both cases had features that differed from previous descriptions. In one case the eruption developed three to four weeks after a single erythemogenic sun exposure and faded after two to three weeks. The rash could be reproduced by exposure to ultraviolet B (UVB) or UVC radiation. In the other patient, the eruption involved the arms and face and spared the trunk, which is a more characteristic site of involvement; it was associated with a history of exacerbation following sun exposure, but the rash could not be reproduced on phototesting.