Cicatricial pemphigoid Brunsting-Perry variant masquerading as neutrophil-mediated cicatricial alopecia.

A 72-year-old male presented with scarring alopecia on the scalp vertex, multiple crusted plaques on the hairline, and a history of vesicular eruption on the face. The scalp showed crusted plaques with loss of follicular ostia. No follicular pustules or compound follicles were present. An initial transverse scalp biopsy showed perifollicular neutrophils, lymphocytes, and plasma cells along with dermal fibrosis. Focal epidermal/dermal and follicular/adventitial dermal clefts were apparent but were thought to be secondary to fibrosis, and the biopsy result was interpreted to represent a neutrophil-mediated cicatricial alopecia. Concurrently, direct immunofluorescence (DIF) analysis showed linear junctional deposition of IgG and C3. A repeat scalp biopsy revealed more prominent epidermal/dermal clefts, fibrosis, mixed infiltrate with neutrophils, lymphocytes, histiocytes, and plasma cells, as well as prominent follicular/adventitial dermal clefts with perifollicular neutrophils. Given the combination of clefts, perijunctional neutrophils, and positive DIF findings, it became clear that this eruption represented the Brunsting-Perry variant of cicatricial pemphigoid. Here, we illustrated that a neutrophil-rich form of cicatricial pemphigoid can masquerade as a neutrophil-mediated scarring alopecia. In evaluating a specimen suspected to be a neutrophil-mediated scarring alopecia, one should be alert to the presence of subepidermal and perifollicular clefting, and consider cicatricial pemphigoid.

Folliculotropic mycosis fungoides driven by DOCK8 immunodeficiency syndrome.

DOCK8 immunodeficiency syndrome (DIDS) represents a rare primary immunodeficiency associated with cutaneous viral infections, allergy, and increased risk of malignancy. We report a case of folliculotropic mycosis fungoides with spontaneous resolution occurring in a patient with DIDS.

An abdominal skin lesion: to lump or split? a case presentation.

Syphilis has many atypical morphologies which can present a diagnostic challenge, especially in patients with HIV/AIDS who may have multiple concurrent conditions. We describe a 41-year-old man with recently diagnosed HIV who was admitted for acute right vision loss and a diffuse rash with involvement of the palms and soles. He received diagnoses of secondary syphilis and Kaposi sarcoma in the setting of AIDS. Examination revealed an unusual dark brown-to-purple umbilicated papule with a necrotic center on the abdomen, raising a diagnostic dilemma. Skin biopsy showed secondary syphilis, despite the concurrent diagnosis of Kaposi sarcoma. The patient was treated with antibiotic and antiretroviral therapy and symptoms resolved. This case aims to share the clinical reasoning behind diagnosing a patient with HIV/AIDS with multiple concurrent conditions and to raise awareness of the many atypical cutaneous manifestations of secondary syphilis.

Spitz melanoma is a distinct subset of spitzoid melanoma.

Melanomas that have histopathologic features that overlap with those of Spitz nevus are referred to as spitzoid melanomas. However, the diagnostic concept is used inconsistently and genomic analyses suggest it is a heterogeneous category. Spitz tumors, the spectrum of melanocytic neoplasms extending from Spitz nevi to their malignant counterpart Spitz melanoma, are defined in the 2018 WHO classification of skin tumors by the presence of specific genetic alterations, such as kinase fusions or HRAS mutations. It is unclear what fraction of "spitzoid melanomas" defined solely by their histopathologic features belong to the category of Spitz melanoma or to other melanoma subtypes. We assembled a cohort of 25 spitzoid melanomas diagnosed at a single institution over an 8-year period and performed high-coverage DNA sequencing of 480 cancer related genes. Transcriptome wide RNA sequencing was performed for select cases. Only nine cases (36%) had genetic alterations characteristic of Spitz melanoma, including HRAS mutation or fusion involving BRAF, ALK, NTRK1, or MAP3K8. The remaining cases were divided into those with an MAPK activating mutation and those without an MAPK activating mutation. Both Spitz melanoma and spitzoid melanomas in which an MAPK-activating mutation could not be identified tended to occur in younger patients on skin with little solar elastosis, infrequently harbored TERT promoter mutations, and had a lower burden of pathogenic mutations than spitzoid melanomas with non-Spitz MAPK-activating mutations. The MAPK-activating mutations identified affected non-V600 residues of BRAF as well as NRAS, MAP2K1/2, NF1, and KIT, while BRAF V600 mutations, the most common mutations in melanomas of the WHO low-CSD category, were entirely absent. While the "spitzoid melanomas" comprising our cohort were enriched for bona fide Spitz melanomas, the majority of melanomas fell outside of the genetically defined category of Spitz melanomas, indicating that histomorphology is an unreliable predictor of Spitz lineage.

Melanocytic tumors with MAP3K8 fusions: report of 33 cases with morphological-genetic correlations.

We report a series of 33 skin tumors harboring a gene fusion of the MAP3K8 gene, which encodes a serine/threonine kinase. The MAP3K8 fusions were identified by RNA sequencing in 28 cases and by break-apart FISH in five cases. Cases in which fusion genes were fully characterized demonstrated a fusion of the 5' part of MAP3K8 comprising exons 1-8 in frame to one of several partner genes at the 3' end. The fusion genes invariably encoded the intact kinase domain of MAP3K8, but not the inhibitory domain at the C-terminus. In 13 (46%) of the sequenced cases, the 3' fusion partner was SVIL. Other recurrent 3' partners were DIP2C and UBL3, with additional fusion partners that occurred only in a single tumor. Clinically, the lesions appeared mainly in young adults (2-59 years of age; median = 18), most commonly involving the lower limbs (55%). Five cases were diagnosed as Spitz nevus, 13 as atypical Spitz tumor, and 15 as malignant Spitz tumor. Atypical and malignant cases more commonly occurred in younger patients. Atypical Spitz tumors and malignant Spitz tumors cases tended to show epidermal ulceration (32%), a dermal component with giant multinucleated cells (32%), and clusters of pigmented cells in the dermis (32%). Moreover, in atypical and malignant cases, a frequent inactivation of CDKN2A (21/26; 77%) was identified either by p16 immunohistochemistry, FISH, or comparative genomic hybridization. Gene expression analysis revealed that MAP3K8 expression levels were significantly elevated compared to a control group of 57 Spitz lesions harboring other known kinase fusions. Clinical follow-up revealed regional nodal involvement in two of six cases, in which sentinel lymph node biopsy was performed but no distant metastatic disease after a median follow-up time of 6 months.

Acute inflammatory edema: A mimicker of cellulitis in critically ill patients.

BACKGROUND: Inpatient dermatology consultations for treatment-refractory or atypical cellulitis are common. In critically ill patients, differentiating cellulitis from its mimickers can be challenging. OBJECTIVE: We describe acute inflammatory edema, a likely underrecognized variant of pseudocellulitis. METHODS: We reviewed the charts of 15 patients with this diagnosis, seen by the inpatient dermatology consultation service at the University of California at San Francisco between 2009 and 2017. RESULTS: The cohort consisted of 9 women and 6 men with an age range of 52-73 years. Acute inflammatory edema presents as bilateral, erythematous, and edematous plaques, most commonly involving the thighs and lower abdomen, sparing areas of increased pressure on the skin. There is a predilection for patients with high body mass index and those with clinical or quantitative findings of fluid overload. CONCLUSION: We propose a 3-part pathogenesis of acute inflammatory edema: 1) acute-onset volume overload 2) in patients with impaired lymphatic return 3) leads to dermal edema, microtears in connective tissue, and an influx of inflammation.

Subcutaneous Panniculitis-Like T-Cell Lymphoma Versus Lupus Erythematosus Panniculitis: Distinction by Means of the Periadipocytic Cell Proliferation Index.

The distinction between subcutaneous panniculitis-like T-cell lymphoma (SPTCL) and lupus erythematosus (LE) panniculitis is remarkably challenging. Rimming by lymphocytes with an elevated Ki-67 cell proliferation index has been forwarded as a potential diagnostic finding in biopsies of SPTCL but has not been rigorously compared with biopsies from patients with LE panniculitis. Nineteen and 17 examples of SPTCL and LE panniculitis, respectively, were evaluated for periadipocytic rimming by lymphocytes expressing Ki-67, CD8, and ßF1 and for attributes associated with LE, including clusters of CD123-positive cells. The identification of periadiopocytic rimming using Ki-67, CD8, and ßF1 held sensitivity of 79%, 100%, and 89.5% and specificity of 100%, 52.9%, and 88.2%, respectively (P < 0.01). CD123-positive cells were in both disorders. LE-like histopathology was commonly encountered in SPTCL. In conclusion, an elevated Ki-67 cell proliferation index with rimming is useful for distinguishing SPTCL from LE panniculitis. Notably, many features of LE panniculitis can also be encountered in SPTCL.

Primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphomas: reappraisal of a provisional entity in the 2016 WHO classification of cutaneous lymphomas.

Primary cutaneous CD8-positive aggressive epidermotropic T-cell lymphoma is a rare and poorly characterized variant of cutaneous lymphoma still considered a provisional entity in the latest 2016 World Health Organization Classification of Cutaneous lymphomas. We sought to better characterize and provide diagnostic and therapeutic guidance of this rare cutaneous lymphoma. Thirty-four patients with a median age of 77 years (range 19-89 years) presented primarily with extensive annular necrotic plaques or tumor lesions with frequent mucous membrane involvement. The 5-year survival was 32% with a median survival of 12 months. A subset of 17 patients had a prodrome of chronic patches prior to the development of aggressive ulcerative lesions. We identified cases with lack of CD8 or αß T-cell receptor expression yet with similar clinical and pathological presentation. Allogeneic stem cell transplantation provided partial or complete remissions in 5/6 patients. We recommend the term primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphoma as this more broad designation better describes this clinical-pathologic presentation, which allows the inclusion of cases with CD8 negative and/or αß/γδ T-cell receptor chain double-positive or double-negative expression. We have identified early skin signs of chronic patch/plaque lesions that are often misdiagnosed as eczema, psoriasis, or mycosis fungoides. Our experience confirms the poor prognosis of this entity and highlights the inefficacy of our standard therapies with the exception of allogeneic stem cell transplantation in selected cases.

Primary cutaneous B-cell lymphomas with large cell predominance-primary cutaneous follicle center lymphoma, diffuse large B-cell lymphoma, leg type and intravascular large B-cell lymphoma.

In this review, we present clinical features and detailed histopathologic, immunologic, and molecular information regarding primary cutaneous follicle center lymphoma and primary cutaneous diffuse large B-cell lymphoma, leg type which together represent two of the three most common types of primary cutaneous B-cell lymphoma recognized in the current WHO classification system.1,2 Overall, B-cell lymphomas represent 19-27% of primary cutaneous lymphomas in most large European and American studies3-6 and together, primary cutaneous follicle center lymphoma and primary cutaneous diffuse large B-cell lymphoma, leg type account for approximately 2/3 to ¾ of these cases.5,7-11 Both subtypes can contain a high content of large B-lymphocytes, although most cases of primary cutaneous follicle center lymphomas exhibit a range in cell size and cytology. Intravascular large B-cell lymphoma, a less commonly-encountered EBV-negative primary cutaneous B-cell lymphoma composed of large cells, will be more briefly discussed in this report as well.

Neutrophil-rich subcutaneous fat necrosis of the newborn: A potential mimic of infection.

BACKGROUND: The inflammatory infiltrate seen in biopsy specimens obtained from patients with subcutaneous fat necrosis of the newborn (SCFN) has classically been described as consisting mostly of histiocytes. However, we encountered patients with SCFN whose biopsy specimens revealed mostly neutrophils, prompting infection to be an initial consideration. OBJECTIVES: We sought to describe cases of SCFN in which neutrophils formed the majority of the infiltrate at our institution and in the literature. METHODS: We performed a retrospective analysis of patients with SCFN reported at our institution and a literature review of SCFN. RESULTS: Thirteen cases of SCFN were identified at our institution. In 2 of 13 cases, neutrophils composed >75% of the inflammatory infiltrate, and both lesions were 1 day old. From the literature review, neutrophils were mentioned as a component of the infiltrate in 10 of 124 cases, but in none were neutrophils described as forming the majority of the infiltrate. LIMITATIONS: This study is limited by its retrospective nature and small sample size. CONCLUSIONS: Neutrophils can comprise most of the inflammatory cells in patients with SCFN, especially early in the course of the disease. This variant of SCFN can be easily mistaken for infection.

SOX-10 expression in cutaneous myoepitheliomas and mixed tumors.

BACKGROUND: SOX-10 expression can be demonstrated by immunohistochemistry in salivary gland myoepitheliomas, but its expression in cutaneous myoepitheliomas and in cutaneous mixed tumors with prominent myoepithelial cells has not been studied. METHODS: We assessed the staining pattern of SOX-10 in five cutaneous myoepitheliomas and six cutaneous mixed tumors with a prominent myoepithelial component among both the myoepithelial cells and cells lining lumens. In addition, we examined the staining of S100, microphthalmia-associated transcription factor (MiTF), keratin cocktail, HMK903, smooth muscle actin (SMA) and epithelial membrane antigen (EMA). RESULTS: SOX-10 positivity was seen in three of five (60%) cutaneous myoepitheliomas and in the myoepithelial cells of all cutaneous mixed tumors. SOX-10 expression on the cells lining the glandular structures in mixed tumors was variable. All myoepitheliomas and mixed tumors stained positively with S100 and negatively with MiTF. Pan-keratin, HMK903, SMA and EMA showed variable expression. CONCLUSIONS: SOX-10 is a relatively reliable marker for staining cutaneous myoepitheliomas. Cutaneous myoepitheliomas are notoriously difficult to diagnose, and the addition of SOX-10 to the repertoire of stains that can label this tumor is of practical utility. These results further support that cutaneous myoepitheliomas and cutaneous mixed tumors exist on a morphologic and immunophenotypic spectrum.

Use of an expanded immunohistochemical panel to distinguish cutaneous Hodgkin lymphoma from histopathologic imitators.

In lymph nodes, classical Hodgkin lymphoma can typically be distinguished from non-Hodgkin lymphoma (NHL) by the presence of Hodgkin and Reed-Sternberg cells that co-express CD30 and CD15. However, anaplastic large cell lymphoma (ALCL) and diffuse large B-cell lymphoma (DLBCL) can show identical features, and some cases of classical Hodgkin lymphoma lack CD15 expression, rendering them difficult to differentiate from CD30-positive NHL. The differential diagnosis of cutaneous Hodgkin lymphoma similarly includes ALCL and DLBCL, and, additionally, tumors of mycosis fungoides. Recent studies have shown that classical Hodgkin lymphoma is of B-cell origin in virtually all cases, and shows at least focal weak expression of the B-cell marker PAX5 and often focal weak expression and no expression of the B-cell markers Oct-2 and BOB.1, respectively. All three of these markers are almost invariably absent in T-cell lymphomas and are strongly expressed in B-cell lymphomas. We report a 40-year-old man with classical Hodgkin lymphoma who developed cutaneous nodules. A biopsy from one revealed Hodgkin/Reed-Sternberg cells with a similar immunophenotype to the diagnostic lymph node biopsy, namely CD30+/CD15+, diffusely but weakly PAX5+, focally weakly Oct-2+ and lacking BOB.1 expression, thereby confirming a diagnosis of cutaneous Hodgkin lymphoma. To our knowledge, this is the first report of the expression pattern of the combination of PAX5, Oct-2 and BOB.1 in the context of cutaneous involvement by Hodgkin lymphoma.

Immunohistochemical prognostication of Merkel cell carcinoma: p63 expression but not polyomavirus status correlates with outcome.

Merkel cell carcinoma (MCC) represents a cutaneous malignancy with high associated mortality. Numerous studies have attempted to define characteristics to more accurately predict outcome. Two recent studies have demonstrated that Merkel cell polyomavirus (MCPyV) seropositivity correlated with a better prognosis, while a third study revealed no difference. Expression of p63 by tumor cell nuclei has been shown to be associated with a worse prognosis in a European cohort. To better understand the relationship between prognosis and MCPyV or p63 status, we used immunohistochemistry to evaluate both attributes in 36 US patients with MCC. Our results show that when considered as a binary variable, p63 expression represents a strong risk factor (p < 0.0001, hazards ratio (HR) = ∞) for shortened survival. In addition, our results show that MCPyV status does not correlate with survival (p = 0.6067, HR = 1.27). Our study corroborates the European observation that p63 immunoexpression is useful as a prognostic tool. Larger studies will need to be performed in order to determine whether p63 status should be included in MCC staging, since our study is limited by its relative small size.

Clinical and Pathological Characteristics and Outcomes Among Patients With Subcutaneous Panniculitis-like T-Cell Lymphoma and Related Adipotropic Lymphoproliferative Disorders.

Importance: There is a knowledge gap about subcutaneous panniculitis-like T-cell lymphoma (SPTCL) owing to its rarity and diagnostic difficulty, resulting in an absence of well-documented large case series published to date. Objective: To generate consensus knowledge by a joint multi-institutional review of SPTCL and related conditions. Design, Setting, and Participants: This retrospective clinical and pathological review included cases initially diagnosed as SPTCL at 6 large US academic centers. All cases were reviewed by a group of pathologists, dermatologists, and oncologists with expertise in cutaneous lymphomas. Through a process of group consensus applying defined clinical and pathological diagnostic criteria, the cohort was classified as (1) SPTCL or (2) adipotropic lymphoproliferative disorder (ALPD) for similar cases with incomplete histopathological criteria for SPTCL designation. Exposures: Cases of SPTCL diagnosed between 1998 and 2018. Main Outcomes and Measures: The main outcome was disease presentation and evolution, including response to therapy, disease progression, and development of hemophagocytic lymphohistiocytosis. Results: The cohort of 95 patients (median [range] age, 38 [2-81] years; female-to-male ratio, 2.7) included 75 cases of SPTCL and 20 cases of ALPD. The clinical presentation was similar for both groups with multiple (61 of 72 [85%]) or single (11 of 72 [15%]) tender nodules mostly involving extremities, occasionally resulting in lipoatrophy. Hemophagocytic lymphohistiocytosis (HLH) was only observed in SPTCL cases. With a mean follow-up of 56 months, 60 of 90 patients (67%) achieved complete remission with a median (range) of 3 (1-7) cumulative therapies. Relapse was common. None of the patients died of disease progression or HLH. Two patients with ALPD eventually progressed to SPTCL without associated systemic symptoms or HLH. Conclusions and Relevance: In this case series of patients initially diagnosed as having SPTCL, results showed no evidence of systemic tumoral progression beyond the adipose tissue. The SPTCL experience in this study confirmed an indolent course and favorable response to a variety of treatments ranging from immune modulation to chemotherapy followed by hematopoietic stem cell transplantation. Morbidity was primarily associated with HLH.

Maintenance of peripheral tolerance through controlled tissue homing of antigen-specific T cells in K14-mOVA mice.

Immunological tolerance is crucial to avoid autoimmune and inflammatory diseases; however, the mechanisms involved are incompletely understood. To study peripheral tolerance to skin-associated Ags, we generated new transgenic mice expressing a membrane-bound form of OVA in skin under the human keratin 14 (K14) promoter (K14-mOVA mice). In contrast to other transgenic mice expressing similar self-Ags in skin, adoptive transfer of Ag-specific T cells does not induce inflammatory skin disease in our K14-mOVA mice. OVA-specific T cells transferred into K14-mOVA mice are activated in lymphoid tissues, undergo clonal expansion, and eventually acquire effector function. Importantly, these Ag-specific T cells selectively up-regulate expression of E-selectin ligand in cutaneous lymph nodes but not in mesenteric lymph nodes and spleen, demonstrating that expression of endogenous self-Ags in skin dictates imprinting of skin tissue homing in vivo. However, an additional inflammatory signal, here induced by tape stripping, is required in K14-mOVA mice to induce T cell migration to skin and development of inflammatory skin disease. Depletion of regulatory CD4(+)CD25(+) T cells did not provoke homing of transferred T cells to skin under steady-state conditions, indicating that these cells are not the key regulators for inhibiting T cell homing in K14-mOVA mice. Both skin-derived and lymph node-resident CD8alpha(+) dendritic cells are responsible for Ag presentation in vivo and induce tolerance to skin Ags, as we show by selective depletion of langerin(+) and CD11c(+) dendritic cells. Taken together, controlled skin homing of T cells is critical for the maintenance of peripheral immune tolerance to epidermal self-Ags.

Association of a Proposed New Staging System for Folliculotropic Mycosis Fungoides With Prognostic Variables in a US Cohort.

Importance: A new cutaneous staging system for folliculotropic mycosis fungoides (FMF) has been purported to better estimate survival compared with the staging system for conventional mycosis fungoides. Objective: To analyze predictive variables associated with survival and evaluate the effectiveness of the newly proposed staging system for estimating overall survival and disease-specific survival (DSS) in a US cohort. Design, Setting, and Participants: This cohort study assessed 195 patients with FMF in the dermatopathology database of the University of California, San Francisco from January 1, 1990, to April 31, 2012, for eligibility. A total of 153 patients were excluded for the following reasons: (1) alternative diagnoses were favored ranging from benign dermatitides to other forms of cutaneous lymphoma; (2) technical problems with slides; and (3) lack of follow-up information. Data were analyzed from January 1, 2018, to August 31, 2020. Main Outcomes and Measures: Kaplan-Meier curves were used to estimate overall survival and DSS for the entire cohort. Possible predictive variables associated with survival were evaluated using Cox proportional hazards regression modeling. Each variable was examined separately, followed by a multiple-variable model. Kaplan-Meier curves were used to estimate overall survival and DSS by subdividing the cohort into early- and advanced-stage cutaneous disease. Results: Forty-two patients were included in the analysis (mean age at diagnosis, 55 [range, 8-89] years; 31 men [74%]). For the entire cohort, the estimated 5-year overall survival rate was 89% (95% CI, 79%-99%); 10-year rate, 78% (95% CI, 63%-92%); and 15-year rate, 58% (95% CI, 31%-85%). Estimated 5- and 10-year DSS rates were 89% (95% CI, 79%-99%); 15-year rate, 80% (95% CI, 61%-99%). For overall survival in the multiple-variable Cox proportional hazards regression model, only age was statistically significant (hazard ratio [HR] per 10-year age increase, 3.1; 95% CI, 1.4-7.2; P = .008), whereas for DSS, only cutaneous disease was statistically significant (HR, 11.4; 95% CI, 1.3-103.0; P = .03). When stage stratified, the 5-year estimated overall survival rate for early-stage disease was 96% (95% CI, 89%-103%); 10-year rate, 82% (95% CI, 65%-98%); and 15-year rate, 65% (95% CI, 33%-97%). For advanced-stage disease, the estimated 5- and 10-year overall survival rates were 70% (95% CI, 41%-98%); the 15-year rate, 53% (95% CI, 16%-89%). For early-stage cutaneous disease, the estimated 5-, 10- and 15-year DSS rates were all 96% (95% CI, 89%-103%). For advanced-stage cutaneous disease, the estimated 5- and 10-year DSS rates were 70% (95% CI, 41%-98%); the 15-year rate, 53% (95% CI, 16%-89%). Conclusions and Relevance: Cox proportional hazards regression modeling demonstrated cutaneous stage to be the only statistically significant predictive variable associated with DSS. Subdividing FMF into early and advanced cutaneous stages was associated with effective estimation of survival in this cohort. Thus, findings suggest that FMF is a heterogeneous disease with early and advanced cutaneous stages; that the new staging system is effective in estimating survival in a US cohort; and that the poor prognosis initially associated with FMF only applies to the advanced cutaneous stage.

Primary Cilia Are Preserved in Cellular Blue and Atypical Blue Nevi and Lost in Blue Nevus-like Melanoma.

Distinguishing cellular blue nevi (CBNs) and atypical CBNs from blue nevus-like melanoma (BNLM) can be diagnostically challenging. Immunohistochemistry may inform the diagnosis in a subset of cases but is not always diagnostic. Further, ancillary molecular testing is expensive and often requires significant tissue to complete. Primary cilia are cell-surface organelles with roles in signal transduction pathways and have been shown to be preserved in conventional melanocytic nevi but lost in melanoma. Immunofluorescence staining of primary cilia can be performed using a single standard-thickness formalin-fixed paraffin-embedded tissue section and has a turnaround time similar to immunohistochemistry. The percentage of tumoral melanocytes retaining a primary cilium is quantified and reported as the ciliation index. In the current study, we explored the utility of the ciliation index in a series of 31 blue nevus-like lesions, including CBNs (12), atypical CBNs (15), and BNLM (4). The average ciliation index for the CBNs was 59±18%, with a median of 60 (range: 28 to 87). The average ciliation index for atypical CBNs was 59±23, with a median of 59 (range: 20 to 93). The average ciliation index for BNLM was 4±3, with a median of 3 (range: 1 to 8). There was no significant difference in ciliation index between the CBN and atypical CBN categories. There was a significant difference between CBN and BNLM and between atypical CBNs and BNLM (P<0.001 for each). Here, we show that ciliation index is a quantitative diagnostic tool useful in the setting of blue nevus-like neoplasms, with benefits including cost and time efficiency.

Marked papillary dermal edema--an unreliable discriminator between polymorphous light eruption and lupus erythematosus or dermatomyositis.

BACKGROUND: The clinical differential diagnosis of photo-distributed papules and plaques includes polymorphous light eruption (PMLE) and lupus erythematosus (LE). These entities share many histopathological features. However, in most contemporary textbooks, a broad band of papillary dermal edema is reported to be characteristic of PMLE and not seen in LE. Nonetheless, older reports describe papillary dermal edema in LE, including acute cutaneous LE (ACLE) in patients with systemic LE (SLE) and early lesions of discoid lupus erythematosus (DLE). Older reports also describe papillary dermal edema in microscopic sections of dermatomyositis (DM). METHODS: Retrospective review. RESULTS: Nine cases of LE (including two patients with acute lesions of SLE, six with DLE and one unclassifiable) and three cases of DM were identified in which sections showed striking papillary dermal edema. Attributes of chronicity, such as epidermal atrophy, follicular plugging and basement membrane thickening, were present concurrently in many sections. CONCLUSIONS: Marked papillary dermal edema does not reliably distinguish PMLE from LE as it can be seen in ACLE, early and late lesions of DLE and DM. This phenomenon has been underemphasized in recent reports and textbooks. Furthermore, papillary dermal edema in chronic lesions of DLE has not been previously reported.