Amicrobial pustulosis of the folds: A case report of a rare variant of neutrophilic dermatosis associated with systemic lupus erythematosus.

Amicrobial pustulosis of the folds (APF) is a rare neutrophilic dermatosis found in association with autoimmune diseases. We present a 49-year-old woman with a history of systemic lupus erythematosus and a recurrent pustular eruption in the cutaneous folds. Histologic examination revealed spongiform pustulosis and dermal neutrophilic infiltrate. The Gram and periodic acid-Schiff stains were negative for bacteria and fungi. A diagnosis of amicrobial pustulosis of the folds was given. While there is no standard treatment, our patient's symptoms resolved following an oral prednisone taper and have not recurred since starting colchicine. The presence of pustules and erosive plaques in skin folds in young women with autoimmune conditions should raise suspicion for APF. The combination of localized neutrophilic spongiosis with intraepidermal or subcorneal pustules in conjunction with dermal changes of a neutrophilic dermatosis is a helpful clue to the diagnosis. If the patient does not already have a diagnosis of an underlying autoimmune condition, a presentation of APF should prompt further screening consisting of a relevant review of symptoms and appropriate assessment for autoimmune antibodies, since APF may precede the diagnosis of autoimmune disorders.

Reactive infectious mucocutaneous eruption due to COVID-19 with erythema-multiforme-like lesions and myeloid cells.

Reactive infectious mucocutaneous eruption (RIME) is a recently described entity in which there is prominent mucositis, most commonly involving the oral and urogenital mucosa, secondary to a variety of pathogens. There is typically minimal cutaneous involvement in RIME. This contrasts with erythema multiforme (EM) in which characteristic targetoid lesions predominate, usually in isolation (EM minor), but in a subset of cases, with severe mucositis (EM major). While the histopathologic features of RIME have not been as well defined, those of EM are characterized by epidermal apoptosis and interface dermatitis with lymphocytes making up the predominant cell type. We report a unique case of RIME in a 16-year-old male with COVID-19 characterized by significant mucositis involving the oral and genital mucosa, as well as numerous targetoid lesions on the trunk and extremities. Histopathologically, there was an inflammatory infiltrate obscuring and disrupting the epidermal interface, associated with epidermal necrosis, and blister formation. The infiltrate was composed of cells with irregular, non-segmented and elongate nuclei, with myeloid and histiocytoid cytomorphology. The cells were positive for myeloperoxidase, CD68, and CD163 (subset) suggesting myeloid lineage. RIME is a rarely reported COVID-19-related eruption, and targetoid lesions and myeloid interface reactions have not been described with RIME.

Wells Syndrome-Like Histologic Pattern Caused by a Permanent Tattoo.

ABSTRACT: Tattoo reactions have become more common as tattoos gain visibility and popularity worldwide. A variety of inflammatory patterns have been described in association with tattoos- more commonly fibrosing, granulomatous, lichenoid, pseudolymphomatous, and spongiotic patterns. To date, there has been one case report of a Wells syndrome-like inflammatory pattern associated with a temporary Henna tattoo. Here we present the first case of a permanent tattoo with resulting flame figures, histologically resembling Wells syndrome. We believe this uncommon histologic pattern might be of interest for pathologists to be aware of.

Lymphocytes in Sweet syndrome: A potential diagnostic pitfall.

BACKGROUND: Patients with Sweet syndrome (SS) have acute onset of cutaneous lesions with characteristic histopathology (dense and diffuse neutrophilic infiltrate, dermal edema, leukocytoclasis and no vasculitis) accompanied by systemic symptoms. Sometimes, only skin lesions with classic histopathologic features are seen. Although SS is considered to be a "neutrophilic dermatosis," lymphocytes are also seen on histological examination. METHODS: We evaluated the cellular infiltrate in 9 biopsies from SS lesions with routine staining and immunohistochemistry. RESULTS: Lymphocytes were present in all biopsies in variable amounts, often exceeding the number of intact neutrophils. Prominent fragmentation of neutrophils rendered some biopsies "lymphocyte-rich" on routine histologic evaluation. Myeloperoxidase was helpful in highlighting the inconspicuous neutrophilic fragments in these cases. Lymphocytes were highlighted with immunohistochemistry, and had a CD3+, CD4+, CD20(-) immunophenotype, with rare CD8+ lymphocytes. CONCLUSION: Awareness of the lymphocytic component of SS is important to avoid diagnostic errors, especially in subcutaneous lesions of SS, in which the lymphocytic infiltrate predominates in the upper parts of the dermis, while the typical neutrophilic infiltrate may be seen only in the deeper dermis and subcutis. The lymphocytic component may potentially help to differentiate lesions of SS from neutrophilic urticarial dermatosis, which has not been reported to contain a significant lymphocytic population.

Pseudo-Bullous Dermatosis Induced by Topical Anesthetic Agent-Clues to This Localized Toxic Reaction.

Eutectic mixture of 2.5% lidocaine and 2.5% prilocaine (EMLA AstraZeneca, DE) is a widely used topical anesthetic cream for preprocedural cutaneous analgesia. In addition to potential clinical cutaneous and systemic adverse effects, EMLA may also induce microscopic changes detectable by light and electron microscopy leading to difficulty in accurate diagnosis. We report the case of a biopsy demonstrating EMLA-induced histopathologic changes. The biopsy was taken from the back of a 5-month-old infant and submitted to rule out psoriasis. Hematoxylin and eosin (H&E) staining of the biopsy demonstrated spongiosis and a noninflammatory subepidermal bulla, raising the histopathologic possibility of epidermolysis bullosa. Further investigation confirmed that EMLA was applied under occlusion before biopsy. A second biopsy without topical anesthetic did not demonstrate a bulla and supported the clinical diagnosis of psoriasiform dermatitis. Our case highlights the importance of awareness of EMLA-induced histopathologic changes to avoid potential misdiagnosis. The histopathologic findings of this case in conjunction with other previously reported cases of EMLA-induced bullae were analyzed. Vacuolization of the basal and suprabasilar layer, pallor and swelling of upper layer epidermal keratinocytes, a pauci-inflammatory cleavage beneath or within the basal layer, basophilic granular karyorrhectic debris in the subepidermal cleft, and congestion of papillary dermal vessels characterized the biopsy findings of this localized adverse reaction.

Linear Sclerodermoid Lupus Erythematosus Profundus in a Child.

Lupus erythematosus panniculitis, also known as lupus profundus, is a variant in the clinicopathological spectrum of lupus erythematosus (LE) affecting about 2%-3% of LE patients. A linear configuration of LE panniculitis has been reported rarely with rare reports describing the coexistence of different forms of cutaneous LE and localized morphea. In this study, the authors present a 9-year-old girl with linear arrangement of subcutaneous nodules on her left forearm. Microscopic findings from 2 biopsies included lymphocytes at the dermoepidermal junction with mild interface dermatitis, a dense lymphocytic infiltrate that was concentrated around adnexae and subcutaneous fat in concert with thickened collagen bundles and mild widening of fibrous septae surrounding fat lobules. Although the clinical differential diagnosis included panniculitis or a sporotrichoid infection, 1 biopsy showed a dense lymphocytic infiltrate histologically bordered on that of cutaneous lymphoid hyperplasia or a late stage of Lyme disease, and a second also demonstrated more prominent sclerodermoid collagen bundles rendering the diagnosis of linear sclerodermoid LE profundus.

Pseudocarcinomatous hyperplasia in anaplastic large cell lymphoma, a mimicker of poorly differentiated squamous cell carcinoma: report of a case and review of the literature.

Pseudocarcinomatous hyperplasia can occasionally be observed in biopsies of CD30-positive lymphoproliferative disorders. It is important to be cognizant of this association, because epithelial hyperproliferation can overshadow large atypical lymphoid cells, leading to an erroneous diagnosis of squamous cell carcinoma (SCC) or keratoacanthoma. Herein, we present a case of anaplastic large cell lymphoma (ALCL) with pseudocarcinomatous hyperplasia simulating a poorly differentiated carcinoma and review the literature on this subject. Immunohistochemical staining with p63 helped delineate the infiltrating tongues of pseudocarcinomatous hyperplasia from the malignant infiltrate. We present this case to raise awareness of the potential for pseudocarcinomatous hyperplasia to occur in the setting of CD30+ lymphoproliferative disorders. Clinicians and dermatopathologists should consider the possibility of ALCL or lymphomatoid papulosis when examining lesions with features of inflamed SCC, especially if the tumor presents on a site or in a patient that is not typical of SCC.

Annular lichenoid dermatitis of youth: a separate entity or on the spectrum of mycosis fungoides? Case report and review of the literature.

Annular lichenoid dermatitis (ALDY) is a rare dermatosis that is most often seen in children and young adults and is characterized by annular patches with raised borders, most frequently on the trunk and the groin. A distinct lichenoid tissue reaction involving the base of the rete, resulting in squared-off rete ridges, helps to differentiate this from other lichenoid dermatoses and mycosis fungoides (MF). Herein, we report an additional case of this condition in a 7-year-boy, whose biopsy exhibited the typical quadrangular rete alteration and also contained distinct aggregates of CD8+ lymphocytes, Langerhans cells and colloid bodies within the involved rete. A literature review with emphasis on the clinical and histopathological differential diagnosis reveals additional clinical features of ALDY to potentially help differentiate this entity from annular presentations of mycosis fungoides.

Athlete's nodule in a figure skater: an unusual presentation.

Sports-related acquired connective tissue nevus or "athlete's nodule" has been reported under a variety of different names. The lesion develops in response to activity causing chronic or repetitive low-grade pressure or irritation activity, which is often a component of athletic training. A case of "athlete's nodule" in a figure skater has been reported. Our case demonstrates the typical histopathologic findings of deposition of normal-appearing collagen bundles arranged haphazardly within the dermis as described in previous reports. Additionally, results of CD34, colloidal iron, and elastic tissue staining have been described. The macular clinical presentation with the absence of significant epidermal change is a unique presentation of athletic nodule. It is the goal of the authors to create increased awareness among pathologists and clinicians in identifying these lesions and to expand the clinical presentation to include nonprotuberant lesions.

Histopathologic Distinguishing Features Between Lupus and Lichenoid Keratosis on the Face.

BACKGROUND: The occurrence of lichenoid keratosis (LK) on the face is not well characterized, and the histopathologic distinction between LK and lupus erythematosus (LE) occurring on the face is often indeterminate. The authors aimed to describe differences between LE and LK occurring on the face by hematoxylin and eosin alone. METHODS: Cases of LK and LE were obtained using computer-driven queries. Clinical correlation was obtained for each lupus case. Other diagnoses were excluded for the LK cases. Hematoxylin and eosin-stained sections were reviewed. RESULTS: Forty-five cases of LK and 30 cases of LE occurring on the face were identified. Shared features included follicular involvement, epidermal atrophy, pigment incontinence, paucity of eosinophils, and basket-weave orthokeratosis. Major differences between LK and LE, respectively, included perivascular inflammation (11%, 90%), high Civatte bodies (44%, 7%), solar elastosis (84%, 33%), a predominate pattern of cell-poor vacuolar interface dermatitis (7%, 73%), compact follicular plugging (11%, 50%), hemorrhage (22%, 70%), mucin (0%, 77%), hypergranulosis (44%, 17%), and edema (7%, 60%). A predominate pattern of band-like lichenoid interface was seen more commonly in LK as compared with LE (93% vs. 27%). CONCLUSIONS: The authors established the occurrence of LK on the face and identified features to help distinguish LK from LE. Follicular involvement, basket-weave orthokeratosis, pigment incontinence, paucity of eosinophils, and epidermal atrophy were not reliable distinguishing features. Perivascular inflammation, cell-poor vacuolar interface, compact follicular plugging, mucin, hemorrhage, and edema favored LE. High Civatte bodies, band-like lichenoid interface, and solar elastosis favored LK.

A Dermatopathologist's Guide to Troubleshooting Immunohistochemistry Part 1: Methods and Pitfalls.

Immunohistochemistry (IHC) is a method by which specific target antigens can be detected in formalin-fixed paraffin-embedded tissue and involves the use of monoclonal or polyclonal antibodies; visualization of specific tissue antigens is achieved through an enzymatic reaction that transforms a colorless chromogen to a colored one. These enzymes may be attached to the antibody through a protein-ligand method (eg, biotin-avidin or biotin-streptavidin) or through a secondary antibody. Epitopes that are masked by protein linkage during formalin fixation are unmasked using a retrieval system that either uses heat (heat-induced epitope retrieval) or proteolytic enzymes (proteolytic-induced epitope retrieval). Part 1 of this review will focus and elaborate on the available methodologies for IHC testing, common problems inherent to each technique, and how they can be resolved. Part 2 will focus on common problems and artifacts encountered during IHC staining, likely causes, and methods for addressing each problem.

A Dermatopathologist's Guide to Troubleshooting Immunohistochemistry--Part 2: Troubleshooting Immunohistochemical Tests in the Laboratory.

Unexpected staining patterns can arise from problems occurring in any of the steps required for IHC, some of which are discussed in part I of this CME series. Whether used to differentiate benign from malignant tumors, identify tumor subtypes, subtypes of hematopoietic malignancies, or identifying targets for therapy, the pathologist must be intimately familiar with the potential pitfalls that are inherent in the IHC methodology to troubleshoot problems in the laboratory, and more importantly, when interpreting immunohistochemical staining, to avoid pitfalls of false-positive or false-negative stains.

Hyperkeratotic variant of porokeratosis in a patient with Hepatitis C virus infection and a concomitant immunosuppressed state.

Porokeratoses are acquired and hereditary disorders of keratinization that share a distinctive lesion characterized by raised keratotic borders corresponding histologically to an angled column of parakeratotic cells, called a cornoid lamella. Although a precise mechanistic explanation is lacking, ultraviolet radiation and immunosuppressed states are considered causally-associated with most cases of acquired porokeratosis. Hepatitis C virus (HCV) infection has been proposed as a link between the immunosuppressed states and development of acquired porokeratosis. Among the various recognized clinical entities that constitute this group, rare cases of hyperkeratotic variants have been described that may pose a diagnostic challenge. Herein we describe a remarkable case of the hyperkeratotic variant of porokeratosis that occurred in a patient with known HIV and HCV infections and a coexisting therapy-related immunosuppressed state. We also provide a review of the relevant literature.

Pompholyx and eczematous reactions associated with intravenous immunoglobulin therapy.

INTRODUCTION: Intravenous immunoglobulin (IVIG) is used to treat many inflammatory and autoimmune disorders and although generally well tolerated, cutaneous side effects occur. OBJECTIVE: We reviewed reports of pompholyx and eczematous reactions associated with IVIG. METHODS: A literature search was performed using the PubMed and MEDLINE databases with the search terms "intravenous immunoglobulin pompholyx," "intravenous immunoglobulin eczema," "intravenous immunoglobulin cutaneous adverse effects," "intravenous immunoglobulin cutaneous effects," "intravenous immunoglobulin skin effects," and "intravenous immunoglobulin adverse effects." Relevant English-language articles or articles in other languages cited in English-language articles were included. RESULTS: We identified 64 cases of eczematous reactions associated with IVIG therapy, including a patient treated on our inpatient consult service. In reported cases, the majority of patients (62.5%) had pompholyx alone or a combination of pompholyx on the hands or feet and two or fewer additional body surfaces involved. The majority of reported cases (75%) experienced the eczematous reaction after their first IVIG treatment. Neurologic conditions were the most common (85.9%) diseases for which IVIG was used. Most patients responded well to topical steroids or did not require treatment. LIMITATIONS: Some reported cases had insufficient descriptions to be included in this review. A literature review may underestimate the frequency of eczematous reactions to IVIG because these reactions are often limited and may not be reported. CONCLUSIONS: With the use of IVIG increasing, it is important for dermatologists to recognize this cutaneous side effect of IVIG.

Sézary syndrome: immunopathogenesis, literature review of therapeutic options, and recommendations for therapy by the United States Cutaneous Lymphoma Consortium (USCLC).

Sézary syndrome (SS) has a poor prognosis and few guidelines for optimizing therapy. The US Cutaneous Lymphoma Consortium, to improve clinical care of patients with SS and encourage controlled clinical trials of promising treatments, undertook a review of the published literature on therapeutic options for SS. An overview of the immunopathogenesis and standardized review of potential current treatment options for SS including metabolism, mechanism of action, overall efficacy in mycosis fungoides and SS, and common or concerning adverse effects is first discussed. The specific efficacy of each treatment for SS, both as monotherapy and combination therapy, is then reported using standardized criteria for both SS and response to therapy with the type of study defined by a modification of the US Preventive Services guidelines for evidence-based medicine. Finally, guidelines for the treatment of SS and suggestions for adjuvant treatment are noted.

Necrolytic acral erythema as a cutaneous marker of hepatitis C: report of two cases and review.

Necrolytic acral erythema (NAE) is a member of the necrolytic erythemas, which include necrolytic migratory erythema (NME), acrodermatitis enteropathica, and various dermopathies secondary to nutritional deficiencies. NAE is distinct from the other necrolytic erythemas by virtue of its consistent association with hepatitis C (HCV) together with the acral distribution of its lesions, in particular, dorsal hands and feet. Although its etiology is unknown, NAE has been reported to respond to zinc replacement, suggesting a causal relationship. Two patients with HCV infection presented with scaly acral plaques and histopathologic features consistent with NAE while also demonstrating atypical palmoplantar accentuation of lesions. Both patients were found to have zinc deficiency, and their lesions responded to zinc supplementation. Awareness of NAE as a unique cutaneous marker for HCV infection is important not only for accurate dermatologic diagnosis but also for appropriate management of associated morbidity and prompt detection of potentially undiagnosed underlying HCV.

A case of sweet syndrome with spleen and lymph node involvement preceded by parvovirus B19 infection, and a review of the literature on extracutaneous sweet syndrome.

A 45-year-old white woman presented with fever, arthalgias, and widespread erythematous papules after a recent Parvovirus B19 infection. Biopsy findings were consistent with classic Sweet syndrome. A splenectomy, which was performed due to radiographic evidence of multiple splenic lesions, revealed a diffuse neutrophil-predominant infiltrate with formation of numerous "abcesses." Her skin lesions recurred several times over the next 6 years, with repeat biopsies showing evidence of recurrent Sweet neutrophilic dermatosis. The initial and recurrent skin eruptions were responsive to systemic steroids. A paratracheal lymph node biopsy was later performed to evaluate widespread lymphadenopathy, which showed complete effacement of nodal architecture by a mixed inflammatory and fibrotic process including neutrophils, with features reminiscent of cat-scratch disease. Special stains, tissue culture studies, and serologies were negative for an infectious etiology, and an extensive evaluation for hematologic or other malignancy was negative. This clinical-pathologic presentation was consistent with Sweet syndrome involving both cutaneous and lymphoreticular (spleen and lymph nodes) sites. This case illustrates the importance of recognizing extracutaneous involvement in Sweet syndrome and differentiating this from infectious, malignant, and other processes. The literature on extracutaneous involvement of Sweet syndrome is reviewed.