Premortem Skin Biopsy Assessing Microthrombi, Interferon Type I Antiviral and Regulatory Proteins, and Complement Deposition Correlates with Coronavirus Disease 2019 Clinical Stage

Apart from autopsy, tissue correlates of coronavirus disease 2019 (COVID-19) clinical stage are lacking. In the current study, cutaneous punch biopsy specimens of 15 individuals with severe/critical COVID-19 and six with mild/moderate COVID-19 were examined. Evidence for arterial and venous microthrombi, deposition of C5b-9 and MASP2 (representative of alternative and lectin complement pathways, respectively), and differential expression of interferon type I-driven antiviral protein MxA (myxovirus resistance A) versus SIN3A, a promoter of interferon type I-based proinflammatory signaling, were assessed. Control subjects included nine patients with sepsis-related acute respiratory distress syndrome (ARDS) and/or acute kidney injury (AKI) pre-COVID-19. Microthrombi were detected in 13 (87%) of 15 patients with severe/critical COVID-19 versus zero of six patients with mild/moderate COVID-19 (P < 0.001) and none of the nine patients with pre-COVID-19 ARDS/AKI (P < 0.001). Cells lining the microvasculature staining for spike protein of severe acute respiratory syndrome coronavirus 2, the etiologic agent of COVID-19, also expressed tissue factor. C5b-9 deposition occurred in 13 (87%) of 15 patients with severe/critical COVID-19 versus zero of six patients with mild/moderate COVID-19 (P < 0.001) and none of the nine patients with pre-COVID-19 ARDS/AKI (P < 0.001). MASP2 deposition was also restricted to severe/critical COVID-19 cases. MxA expression occurred in all six mild/moderate versus two (15%) of 13 severe/critical cases (P < 0.001) of COVID-19. In contrast, SIN3A was restricted to severe/critical COVID-19 cases co-localizing with severe acute respiratory syndrome coronavirus 2 spike protein. SIN3A was also elevated in plasma of patients with severe/critical COVID-19 versus control subjects (P ≤ 0.02). In conclusion, the study identified premortem tissue correlates of COVID-19 clinical stage using skin. If validated in a longitudinal cohort, this approach could identify individuals at risk for disease progression and enable targeted interventions.

The histologic and molecular correlates of COVID-19 vaccine-induced changes in the skin

A total of 22 patients who had developed an adverse cutaneous reaction to the Moderna or Pfizer vaccine underwent biopsies. Each patient was assessed light microscopically, and, in select biopsies, spike glycoprotein and cytokine assessment were also conducted. The patients developed self-limited cutaneous reactions often described clinically as urticarial or eczematous within 1 day to 4 weeks after receiving the first or second dose of the Pfizer or Moderna vaccine. Classic clinical and morphologic depictions of type IV cutaneous hypersensitivity with features of eczematous dermatitis, interface dermatitis, granulomatous inflammation, and/or lymphocytic vasculitic component were observed. Clinical and/or histologic features of perniosis, pityriasis rosea, pityriasis rubra pilaris, and guttate psoriasis were seen in select cases. In 2 cases the dominant picture was urticarial vasculitis, possibly reflective of an Arthus type III immune complex action. The biopsy specimens of normal skin post vaccine and of skin affected by the post-vaccine eruption showed rare deep microvessels positive for spike glycoprotein with no complement deposition contrasting with greater vascular deposition of spike protein and complement in skin biopsies from patients experiencing severe coronavirus disease 2019 (COVID-19). It is concluded that self-limited hypersensitivity reactions to the vaccine occur possibly owing to a substance found in the vaccine vehicle (eg, polyethylene glycol). An immune response that is directed against human-manufactured spike has to be considered because some of the reactions clinically and or histologically closely resemble mild COVID-19. Finally, vaccine-associated immune enhancement largely attributable to the adjuvant properties of the vaccine may unmask certain inflammatory milieus operational in psoriasis, atopic dermatitis, and subclinical hypersensitivity.

The skin as a critical window in unveiling the pathophysiologic principles of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease 2019 (COVID-19), is a single-stranded RNA virus whose sequence is known. COVID-19 is associated with a heterogeneous clinical phenotype ranging from asymptomatic to fatal disease. It appears that access to nasopharyngeal respiratory epithelia expressing angiotensin-converting enzyme (ACE) 2, the receptor for SARS-CoV-2, is followed by viral replication in the pulmonary alveolar septal capillary bed. We have demonstrated in earlier studies that incomplete viral particles, termed pseudovirions, dock to deep subcutaneous and other vascular beds, potentially contributing to the prothrombotic state and systemic complement activation that characterizes severe and critical COVID-19. A variety of skin eruptions have been described in the setting of SARS-CoV-2 infection and more recently, after COVID-19 vaccination. The vaccines deliver a laboratory-synthesized mRNA that encodes a protein that is identical to the spike glycoprotein of SARS-CoV-2, allowing the production of immunogenic spike glycoprotein that will then elicit T cell and B cell adaptive immune responses. In this contribution, we review an array of cutaneous manifestations of COVID-19 that provide an opportunity to study critical pathophysiologic mechanisms that underlie all clinical facets of COVID-19, ranging from asymptomatic/mild to severe and critical COVID-19. We classify cutaneous COVID-19 according to underlying pathophysiologic principles. In this regard we propose three main pathways: (1) complement mediated thrombotic vascular injury syndromes deploying the alternative and mannan binding lectin pathways and resulting in the elaboration of cytokines like interleukin 6 from endothelium in the setting of severe and critical COVID-19 and (2) the robust T cell and type I interferon-driven inflammatory and (3) humoral-driven immune complex mediated vasculitic cutaneous reactions observed with mild and moderate COVID-19. Presented are novel data on cutaneous vaccine reactions that manifest a clinical and morphologic parallel with similar eruptions observed in patients with mild and moderate COVID-19 and in some cases represent systemic eczematoid hypersensitivity reactions to a putative vaccine-based antigen versus unmasking subclinical hypersensitivity due to immune enhancing effects of the vaccine. Finally, we demonstrate for the first time the localization of human synthesized spike glycoprotein after the COVID-19 vaccine to the cutaneous and subcutaneous vasculature confirming the ability of SARS-CoV-2 spike glycoprotein to bind endothelium in the absence of intact virus.

Targetoid lesions in a patient with systemic lupus erythematosus

Rowell Syndrome is a rare presentation of lupus erythematosus manifesting as an eruption of erythema multiforme-like papules and plaques with immunological findings of positive rheumatoid factor, speckled antinuclear antibodies, and/or anti-Ro/La antibodies. This case highlights the unusual and highly debated presentation of Rowell Syndrome in a 66-year-old woman with newly-appearing erythematous, targetoid plaques in the setting of previously diagnosed systemic lupus erythematosus. Skin biopsy revealed histological features of full-thickness epidermal necrosis with focal sub-epidermal separation and a superficial perivascular lymphocytic infiltrate interpreted to favor Rowell Syndrome given her clinical history and presentation. Although no standard treatment exists, a prednisone taper and topical corticosteroids proved effective initially, with complete resolution at six months on mycophenolate mofetil and belimumab.

Severe COVID-19: A multifaceted viral vasculopathy syndrome

The objective of this study was to elucidate the pathophysiology that underlies severe COVID-19 by assessing the histopathology and the in situ detection of infectious SARS-CoV-2 and viral capsid proteins along with the cellular target(s) and host response from twelve autopsies. There were three key findings: 1) high copy infectious virus was limited mostly to the alveolar macrophages and endothelial cells of the septal capillaries; 2) viral spike protein without viral RNA localized to ACE2+ endothelial cells in microvessels that were most abundant in the subcutaneous fat and brain; 3) although both infectious virus and docked viral spike protein was associated with complement activation, only the endocytosed pseudovirions induced a marked up-regulation of the key COVID-19 associated proteins IL6, TNF alpha, IL1 beta, p38, IL8, and caspase 3. Importantly, this microvasculitis was associated with characteristic findings on hematoxylin and eosin examination that included endothelial degeneration and resultant basement membrane zone disruption and reduplication. It is concluded that serious COVID-19 infection has two distinct mechanisms: 1) a microangiopathy of pulmonary capillaries associated with a high infectious viral load where endothelial cell death releases pseudovirions into the circulation, and 2) the pseudovirions dock on ACE2+ endothelial cells most prevalent in the skin/subcutaneous fat and brain that activates the complement pathway/coagulation cascade resulting in a systemic procoagulant state as well as the expression of cytokines that produce the cytokine storm. The data predicts a favorable response to therapies based on either removal of circulating viral proteins and/or blunting of the endothelial-induced response.

Docked severe acute respiratory syndrome coronavirus 2 proteins within the cutaneous and subcutaneous microvasculature and their role in the pathogenesis of severe coronavirus disease 2019

The purpose of this study was to examine the deltoid skin biopsy in twenty-three patients with coronavirus disease 2019 (COVID-19), most severely ill, for vascular complement deposition and correlate this with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA and protein localization and ACE2 expression. Deltoid skin microvascular complement screening has been applied to patients with various systemic complement-mediated microvascular syndromes, best exemplified by atypical hemolytic uremic syndrome. In 21 of 23 cases, substantial microvascular deposition of complement components was identified. The two patients without significant complement deposition included one patient with moderate disease and a severely ill patient who although on a ventilator for a day was discharged after 3 days. The dominant microvascular complement immunoreactant identified was the terminal membranolytic attack complex C5b-9. Microvascular complement deposition strongly colocalized in situ with the SARS-CoV-2 viral proteins including spike glycoproteins in the endothelial cells as well as the viral receptor ACE2 in lesional and nonlesional skin; viral RNA was not evident. Microvascular SARS-CoV-2 viral protein, complement, and ACE2 expression was most conspicuous in the subcutaneous fat. Although the samples from severely ill patients with COVID-19 were from grossly normal skin, light microscopically focal microvascular abnormalities were evident that included endothelial cell denudement, basement membrane zone reduplication, and small thrombi. It is concluded that complement activation is common in grossly normal skin, especially in the subcutaneous fat which may provide a link between severe disease and obesity, in people with severe COVID-19, and the strong colocalization with the ACE2 receptor and viral capsid proteins without viral RNA suggests that circulating viral proteins (ie, pseudovirions) may dock onto the endothelial of these microvessels and induce complement activation.

The differing pathophysiologies that underlie COVID-19-associated perniosis and thrombotic retiform purpura: a case series

Background

There are two distinctive acral manifestations of COVID‐19 embodying disparate clinical phenotypes. One is perniosis occurring in mildly symptomatic patients, typically children and young adults; the second is the thrombotic retiform purpura of critically ill adults with COVID‐19.

Objectives

To compare the clinical and pathological profiles of these two different cutaneous manifestations of COVID‐19.

Methods

We compared the light microscopic, phenotypic, cytokine and SARS‐CoV‐2 protein and RNA profiles of COVID‐19‐associated perniosis with that of thrombotic retiform purpura in critical patients with COVID‐19.

Results

Biopsies of COVID‐19‐associated perniosis exhibited vasocentric and eccrinotropic T‐cell‐ and monocyte‐derived CD11c⁺, CD14⁺ and CD123⁺ dendritic cell infiltrates. Both COVID‐associated and idiopathic perniosis showed striking expression of the type I interferon‐inducible myxovirus resistance protein A (MXA), an established marker for type I interferon signalling in tissue. SARS‐CoV‐2 RNA, interleukin‐6 and caspase 3 were minimally expressed and confined to mononuclear inflammatory cells. The biopsies from livedo/retiform purpura showed pauci‐inflammatory vascular thrombosis without any MXA decoration. Blood vessels exhibited extensive complement deposition with endothelial cell localization of SARS‐CoV‐2 protein, interleukin‐6 and caspase 3; SARS‐CoV‐2 RNA was not seen.

Conclusions

COVID‐19‐associated perniosis represents a virally triggered exaggerated immune reaction with significant type I interferon signaling. This is important to SARS‐CoV‐2 eradication and has implications in regards to a more generalized highly inflammatory response. We hypothesize that in the thrombotic retiform purpura of critically ill patients with COVID‐19, the vascular thrombosis in the skin and other organ systems is associated with a minimal interferon response. This allows excessive viral replication with release of viral proteins that localize to extrapulmonary endothelium and trigger extensive complement activation.

Follicular psoriasis: a report of 5 cases and review of the literature, likely an under-recognized yet distinctive variant of psoriasis

Psoriasis is a common autoimmune dermatosis representing an interplay between certain genetic predisposing factors along with clonally restricted Th1 T cells responding to epidermal keratinocyte derived antigen. A unique IL17/IL23 cytokine-rich milieu is pathogenetically significant and conducive to its salient histomorphologic features, such as epidermal hyperplasia and intraepidermal influx of neutrophils. The classic cutaneous manifestation is that of plaque psoriasis also referred to as psoriasis vulgaris with characteristic well-circumscribed erythematous plaques covered by silvery scales. Follicular psoriasis is an uncommon variant manifesting as a scaly folliculocentric hyperkeratotic eruption of the trunk and extremities, irrespective of the presence or absence of conventional lesions of psoriasis vulgaris. In this study we present 5 cases of follicular psoriasis, review the literature, and provide a proposal regarding relevant pathologic findings and potential pathogenetic mechanisms. The incidence of follicular psoriasis is unknown, emphasizing its rarity given the overall incidence of conventional psoriasis in the general population. Owing to the lack of awareness, this clinical presentation is often mistaken for other follicular dermatoses, including bacterial folliculitis, pityriasis rubra pilaris, keratosis pilaris, or follicular eczema.

Histopathology of sabra dermatitis: A case report

Sabra dermatitis (SD) is a form of irritant contact dermatitis caused by penetration of small, hair-like glochids from Opuntia cactus into the skin. SD is a common problem among the farmers who are in close contact with prickly pears; however, the histopathologic criteria for this condition are not well defined. The purpose of this article is to present a well-documented case of SD and to acquaint pathologists with the entity.

A case of generalized red sweating

We report a case of a 70-year-old man with a 5-year history of red pigmented sweating on the axillae, groin, forearms, trunk, and and peri-nuchal sites. No identifiable cause of the pigmented sweat was identified. Biopsy revealed lipofuscin pigment leading to the diagnosis of idiopathic chromhidrosis. This case represents an unusual presentation of chromhidrosis that was not limited to the apocrine sweat gland distribution and ultimately revealed no identifiable cause. After failing multiple treatment options, the patient elected for a trial of treatment with 20% aluminum chloride solution.

Follicular cutaneous squamous cell carcinoma: an under-recognized neoplasm arising from hair appendage structures

BACKGROUND

Cutaneous squamous cell carcinoma (SCC) with no demonstrable point of epidermal origin is problematic as it raises consideration of metastatic SCC histologically. There are rare case reports and series of SCC arising from the wall of hair follicle structures. Such lesions have been termed follicular SCC (FSCC).

OBJECTIVES

To investigate the clinicopathological features of FSCC.

METHODS

We prospectively collected cases of follicular SCC over a 5-year period. Follicular SCC is defined as a cutaneous SCC deriving from a pre-existing hair follicle structure. Lesions were considered to represent 'hybrid' SCCs if an interfollicular epidermal origin was also demonstrated; SCCs with > 50% of the origin from interfollicular epidermis were excluded. Histological features and clinical information were evaluated.

RESULTS

We identified 61 cases of follicular SCC arising in 60 patients from a database of 5212 cutaneous SCCs encountered over the same time period by the same authors. There were 49 pure follicular SCCs and 12 hybrid lesions. The male to female ratio was 44 : 16; the mean age was 74 years (range 44-93). Follicular SCC represents 1·2% of all primary SCCs. Biopsies of such lesions, if the appendage structure of origin is not represented, are histologically indistinguishable from metastatic SCC.

CONCLUSIONS

Recognition of this under-reported form of SCC is essential if an inappropriate diagnosis of metastatic SCC, with potentially harmful and inappropriate therapy and investigation, is to be avoided.

The role of sentinel lymph-node biopsy in the management of cutaneous melanoma

The use of the sentinel lymph node biopsy (SLNB) procedure has developed from an experimental technique to one that is now widely accepted for carcinoma of the breast and for cutaneous melanoma. The status of the sentinel lymph node strongly correlates with survival in patients with melanoma, and it is used in many centers to determine which patients would benefit from elective lymph node dissection and possible chemotherapy. There is emerging yet still not decisive evidence that, when combined with completion lymphadenectomy, SLNB may prolong survival in patients with metastatic disease; however, controversy continues over the lower limit of defining how large a metastatic tumor deposit must be to be meaningful. In addition, many centers are considering SLNB to help stratify risk in melanocytic lesions of uncertain malignant potential.

Sinonasal non-keratinizing squamous cell carcinoma with nasal skin extension as the initial presentation

Sinonasal non-keratinizing squamous cell carcinoma (SCC), previously designated as transitional cell carcinoma or cylindrical cell carcinoma, is an uncommon malignant neoplasm with distinct histopathological features, considered to be a low-grade malignancy that usually occurs in elderly patients. Extensive local invasion is uncommon. Here we report a case of 90-year-old woman whose original presentation was as erythematous nasal skin nodules, biopsy of which showed a dermal tumor with features of sinonasal non-keratinizing SCC. No epidermal dysplasia was present. A subsequent computed tomography scan confirmed the presence of an endophytic tumor on the nasal sidewall. The initial presentation of sinonasal non-keratinizing SCC as a skin lesion is previously unreported to our knowledge. Diagnosis in this context requires accurate evaluation of the histopathology as well as a comprehensive knowledge of pathology specific to this anatomic location.

Soluble adenylyl cyclase antibody profile as a diagnostic adjunct in the assessment of pigmented lesions

OBJECTIVE

To investigate the usefulness of a novel marker for melanocytic proliferations.

DESIGN

Using a novel monoclonal antibody against soluble adenylyl cyclase (sAC), various benign and malignant melanocytic proliferations were immunostained.

SETTING

Weill Medical College of Cornell University dermatopathology laboratory.

MAIN OUTCOME MEASURES

The results were qualitative, not quantifiable.

RESULTS

The sAC immunostaining produced distinctive patterns that paralleled melanomagenesis. At one pole of the spectrum were benign nevi, including atypical nevi of special sites and recurrent nevi showing a distinct pattern of dotlike Golgi staining, while at the opposite pole was melanoma, in which many cells demonstrated an intense pannuclear expression pattern, often accompanied by loss of the Golgi expression pattern. Melanomas of lentigo maligna and acral lentiginous subtypes exhibited the most striking pannuclear expression, while nodular melanomas showed the least, although with supervening enhanced diffuse cytoplasmic expression. Loss of the Golgi expression pattern was a feature of malignant melanoma.

CONCLUSION

The sAC expression pattern is complex but seems discriminatory, with distinctive and variable staining patterns according to the nature of the lesion biopsied.

Acantholytic squamous cell carcinoma: is it really a more-aggressive tumor?

BACKGROUND

Acantholytic squamous cell carcinoma (ASCC) is frequently considered to be a more-aggressive variant with worse prognosis than other squamous cell carcinoma (SCC) subtypes.

OBJECTIVES

To analyze the biologic behavior of ASCC.

METHODS

We conducted a literature search of articles in English plus a manual search of cited references and common dermatology textbooks.

RESULTS

We found no comprehensive study on the biologic behavior of ASCC. Published data are scant, anecdotal, and contradictory. Of the articles investigated, the recurrence and metastasis rates ranged from 6% to 10% and 2% to 43%, respectively.

CONCLUSION

Analysis of the published evidence does not support the assumption that ASCC is a more-aggressive tumor with higher potential for recurrence or metastasis. As with other SCC types, prognosis is more dependent on the characteristics of the host and the location, size, depth, differentiation, and previous treatment of tumors. The treatment and follow-up of patients with ASCC should be similar to those for other types of SCC. The authors have indicated no significant interest with commercial supporters.

Folliculotropic T-cell lymphocytosis as a distinct form of pilotropic T-cell dyscrasia

Cutaneous T-cell dyscrasia represents a heterogeneous group of persistent clonal and usually epitheliotropic T-cell infiltrates with a seemingly low risk for progression to mycosis fungoides (MF). Mucin-poor folliculotropic T-cell lymphocytosis is the least well characterized with only a few anecdotal case reports. Cases of folliculotropic lymphocytosis were retrieved via a natural language search from 2 dermatopathology databases. Comprehensive light microscopic, phenotypic, and molecular studies were conducted. There were 12 females and 12 males, with mean age of 41 years. There were 2 main clinical presentations: facial erythematous infiltrative papules and/or nodules vs extremity and truncal solitary, large, scaly plaques. The mean duration of the lesions was 3 years. Progression to follicular MF was noted in 1 case. Migration of small lymphocytes into the superficial portions of the hair follicle unaccompanied by other inflammatory cells or mucin was observed; lymphocytes with a cerebriform appearance could be seen. The CD4/CD8 ratio was more than 5:1 with significant reductions in the expression of CD62L and CD7. Of 20 cases tested, 5 showed monoclonality. Folliculotropic T-cell lymphocytosis is a form of pilotropic T-cell dyscrasia distinct from MF and alopecia mucinosa; the course seems indolent in most cases.

De novo intraepidermal epithelioid melanocytic dysplasia: an emerging entity

De novo intraepidermal epithelioid melanocytic dysplasia represents a distinctive form of intraepidermal melanocytic dysplasia. Although these lesions are atypical, they are not diagnostic of melanoma. They are considered a part of the atypical mole phenotype and may define a point in the natural course of melanomagenesis.

Basosquamous carcinoma

BACKGROUND

Basosquamous carcinoma is considered an aggressive type of basal cell carcinoma (BCC) with an increased risk of recurrence and metastases. This concept has been perpetuated in the literature in spite of confusing terminology, limited scientific data, and the contradictory surgical experiences of some observers.

METHODS

This is a narrative review based on a MEDLINE search of articles in English and a manual search of popular dermatology textbooks to define basosquamous carcinoma, its incidence, clinical behavior, and treatment of choice.

RESULTS

There are no specific clinical features to distinguish basosquamous carcinoma from other BCC types and the diagnosis is made only after biopsy. There are several histologic definitions of basosquamous carcinoma ranging from a characteristic combination of BCC and squamous cell carcinoma with or without a transition zone, to any BCC with evidence of keratinization. The authors confine the use of the term to an infiltrative growth BCC with areas of keratinization and/or intercellular bridge formation in the setting of a prototypic proliferative stromal reaction. The term "metatypical basal cell carcinoma" is considered a synonym but its use is discouraged for the reasons outlined. The reported incidence of basosquamous carcinoma ranges from 1.2% to 2.7%. Published recurrence rates are 12% to 51% for surgical excision and 4% for Mohs micrographic surgery. The incidence of metastasis is at least 5%. The aggressive biological behavior and clinical course distinguish basosquamous carcinoma from other forms of BCC.

LIMITATIONS

This study is a literature review, contains a limited number of patients, and is mostly retrospective studies.

CONCLUSION

The terminology surrounding basosquamous carcinoma is confusing and there is a need for more uniform language. Based on our review and personal experience, we propose a more precise and specific definition. Data regarding the incidence, recurrence, and metastasis rates of basosquamous carcinoma are based mostly on retrospective series with a limited number of cases. We conclude that although the incidence of basosquamous carcinoma is unknown, there is a literature precedent suggesting more aggressive biological behavior. We believe that complete surgical excision is the preferred approach, and that basosquamous carcinoma is an ideal candidate lesion for Mohs micrographic surgery.

Interface dermatitis

Interface dermatitis can be classified based upon the cell type that dominates the infiltrate (ie, neutrophilic, lymphocytic, or lymphohistiocytic) or by the intensity of the interface inflammation. Regarding lymphocytic interface dermatitis, there are 2 broad categories: cell-poor interface dermatitis, when only a sparse infiltrate of inflammatory cells is present along the dermoepidermal junction, or cell rich, which typically occurs as a heavy bandlike infiltrate that obscures the basal layers of the epidermis. In the case of lymphocytic interface dermatitis, the latter is often termed a lichenoid interface dermatitis. This review focuses upon the mononuclear cell-predominant forms of interface dermatitis.

The molecular basis of melanomagenesis and the metastatic phenotype

The last two decades have seen spectacular advances in our understanding of the biology of melanoma and, in particular, have elucidated the mechanisms operative in disease initiation and progression. With respect to the former, the genetics of melanoma and in particular the impact of genetic defects on dysregulation of the cell cycle are key issues in malignant transformation and are a major focus of this review. With respect to the latter, consideration also is given to the acquisition of growth factor autonomy and the capacity for invasion and metastasis from the standpoint of cell adhesion, motility, and matrix digestion. These events have specific morphologic correlates that will be briefly addressed. Where relevant, we will address certain of the modern pharmacogenetic strategies that flow from these novel observations concerning melanoma biology.

Malignant proliferating pilar tumors arising in KID syndrome: a report of two patients

We report on two young adults with KID syndrome and follicular hyperkeratosis, hidradenitis suppurativa of the groin, progressive development of proliferative pilar cysts and dissecting cellulitis of the scalp, who developed metastatic malignant pilar tumors. Based on our findings, we believe that cancer surveillance in patients with KID syndrome should include screening for pilar tumors and their early removal to avoid development of malignant proliferating pilar tumors with poor prognosis.

Unusual histologic and clinical variants of melanoma: Implications for therapy

Unusual histologic variants of melanoma may be problematic to the histopathologist. Several of these variants are sufficiently rare that their biologic behavior remains obscure. As identification of some of these melanoma subtypes has specific implications for the therapeutic approach, and as some may mimic other forms of epithelial or mesenchymal neoplasia, their recognition is key to patient management.

Clonality in the setting of Sweet's syndrome and pyoderma gangrenosum is not limited to underlying myeloproliferative disease

BACKGROUND

The neutrophilic dermatoses encompass, among others, Sweet's syndrome (SS) and pyoderma gangrenosum (PG), which are associated with underlying systemic diseases including myeloid dyscrasias.

METHODS

On skin biopsies from 16 patients with biopsy-proven SS and/or PG, we performed an X-inactivation assay to detect clonal restriction of neutrophils. There were two patient categories based on known diseases at the time of diagnosis: patients with myeloproliferative disease and patients without myeloproliferative disease.

RESULTS

Among seven patients with acute myelogenous leukemia and two with myelodysplastic syndrome, clonal restriction was found in five; three were homozygous, precluding analysis. Among the seven control patients, infiltrates were clonally restricted in five; one was polyclonal and the other was homozygous for the allele, precluding analysis. Of the five patients with clonally restricted infiltrates, one was subsequently diagnosed with myelodysplasia, one had unexplained neutropenia and an additional patient developed breast cancer. Overall, the incidence of clonality in both groups was the same, averaging 81%.

CONCLUSION

These findings suggest that clonality in neutrophilic dermatoses, while characteristic of underlying myeloid dyscrasia, is not observed exclusively in the setting of myeloproliferative diseases. The significance of clonal neutrophilic infiltrates unassociated with myeloproliferative disease is unclear, but it may have some implications regarding the pathogenesis of sterile neutrophilic infiltrates. Clonality is well described in the setting of lymphomatoid hypersensitivity, reflecting an overzealous response to antigenic stimuli. One could speculate a similar mechanism operational in cases of apparently reactive SS/PG associated with monoclonality; a localized form of cutaneous neutrophilic dyscrasia is also possible.

Pigmented purpuric dermatosis: classification by phenotypic and molecular profiles

The categorization of pigmented purpuric dermatosis (PPD) as a form of cutaneous lymphoid dyscrasia has been suggested. Phenotypic and molecular studies were done on 43 patients with PPD. The molecular studies used a capillary gel electrophoresis T-cell receptor beta multiplex polymerase chain reaction assay. There were 2 principal categories: polyclonal PPD represented by 22 cases and monoclonal variants comprising 21 cases. Monoclonal cases had extensive skin lesions. An identical restricted T-cell repertoire independent of time and location was observed. Approximately 40% of the monoclonal cases had clinical and pathologic features of mycosis fungoides (MF). In the polyclonal variant, disease outside the lower extremities was uncommon; there were no patients with MF. Striking reductions in CD7 and CD62L were seen in both groups. PPD is a form of cutaneous T-cell lymphoid dyscrasia, based on the frequency of monoclonality, the preservation of persistent T-cell clonotypes, and extent of pan-T-cell marker loss. Stratification of lesions of PPD according to the molecular profile may be of significant value prognostically and influence therapeutic intervention.

Pityriasis lichenoides chronica: stratification by molecular and phenotypic profile

Pityriasis lichenoides (PL) has traditionally been classified as a benign papulosquamous disease. However, there is an increasing literature precedent that suggests that PL should instead be considered a form of cutaneous lymphoid dyscrasia. We prospectively encountered 46 patients with a diagnosis of PL and used immunohistochemical and multiplex polymerase chain reaction fragment size analysis to assess for phenotypic abnormalities and for T-cell clonal restriction, respectively. We categorized them into 2 groups based on the molecular profile, namely, those cases that showed a monoclonal and/or a restricted oligoclonal profile versus those cases that were polyclonal. Half of all the cases studied showed a monoclonal and/or an oligoclonal restricted T-cell repertoire. From a clinical perspective, 2 cases in this group manifested skin lesions compatible with mycosis fungoides (MF). All of the other cases demonstrated a persistent but nonprogressive clinical course characterized by periods of regression and recurrence. In any case in which there were multiple biopsies, the same T-cell dominant clonotypes, be it in the context of representing a true monoclonal and/or oligoclonal pattern, were implicated over time and at different biopsy sites, including 2 cases in which there was a subsequent evolution to MF. Substantial losses of CD7 and CD62L were seen in both monoclonal/oligoclonal and polyclonal cases of PL, although both values of percentage reduction were greater in the monoclonal/oligoclonal cases. A dominance of CD8 lymphocytes was seen in more than half of all the cases of PL and held to be reactive in nature, potentially directed against clonally restricted CD4 cells. CD4/CD25+ (Foxp3+) T cells averaged 24% in the polyclonal cases; it was 12% in the monoclonal variants of PL. We conclude that PL is a form of indolent cutaneous T-cell dyscrasia. The limited propensity for progression to MF may reflect internal countercheck mechanisms of controlling clonally restricted CD4+ T-cell proliferations via CD8 and CD4/CD25+ regulatory T cells.

Cytomegalovirus-associated cutaneous vasculopathy and scleroderma sans inclusion body change

Viruses have long been held to be of pathogenetic importance in the evolution of autoimmune connective tissue disease. We describe 7 adults who developed cutaneous connective tissue disease stigmata in temporal association with recent cytomegalovirus (CMV) infection but without the classic cytopathic changes of CMV infection. We examined 7 adults with clinical presentations encompassing cutaneous vasculitis in 4 and scleroderma in 3. In all 7 patients, there was either IgM seropositivity for CMV and/or CMV DNA isolation from peripheral blood. Although no CMV inclusions were seen, in situ hybridization studies revealed very focal CMV RNA transcript expression with localization mainly to the endothelium. The patients with vasculitis treated with ganciclovir had improvement or resolution of symptoms, whereas only 1 patient with scleroderma received antiviral therapy, without benefit. Another scleroderma patient responded to infliximab therapy. Abortive/partial CMV reactivation can be associated with a syndrome complex mimicking and/or triggering a primary immune-based cutaneous microvascular injury syndrome. Antiviral therapy appears to be of therapeutic value in those cases associated with active necrotizing vasculitic changes. The role of tumor necrosis factor alpha blockers in scleroderma cases temporally associated with CMV infection requires further evaluation.

Imiquimod as an antiaging agent

BACKGROUND

Topical imiquimod therapy has proven to be effective for a variety of infectious, neoplastic, and inflammatory dermatologic diseases. Several published reports have validated the benefit of imiquimod therapy for actinic keratoses and superficial melanoma and nonmelanoma skin cancers. There is, however, limited evidence demonstrating the use of topical imiquimod application as an antiaging treatment.

OBJECTIVES

We examined the effectiveness of imiquimod 5% cream in the treatment of photoaging by evaluating pretreatment and posttreatment biopsy specimens and documenting the histologic changes.

METHODS

This study represents an extension of an earlier project in our department in which patients with biopsy-proven lesions of lentigo maligna (LM) were recruited from a university dermatology service, a hospital, and referrals from private practitioners for an open-labeled efficacy trial with daily topical application of 5% imiquimod for 3 months. Biopsy of clinically affected skin was carried out on all patients before and after treatment. Using a semiquantitative method, biopsy specimens were analyzed for changes in the dermal collagen table (solar elastosis vs papillary dermal fibroplasia). Additional parameters analyzed included epidermal changes (atrophy vs acanthosis, melanin content, and hypergranulosis) and inflammatory effects (epidermal and dermal cell populations along with presence of pigment incontinence). Variables were compared using paired Wilcoxan rank sums.

RESULTS

Of 26 evaluable patients who completed 3 months of daily application, 24 (>92.3%) showed a significant increase in papillary dermal fibroplasia (P < .0001) with associated reduction in solar elastosis (P = .0036). Other noteworthy findings were restoration of normal epidermal thickness (P = .0073) and melanization (P < .0001).

LIMITATIONS

This study only evaluates the effect of imiquimod in the lesional skin of LM. It is not known whether the results are applicable to nonlesional, photoaged skin.

CONCLUSION

Topical imiquimod appears to induce reparative changes to the epidermis and the dermal collagen table in chronically sun-damaged skin associated with LM, indicating its potential use as an antiaging treatment. These findings need to be confirmed in photodamaged skin not associated with LM.