Clinical validation of digital assessment tools and machine learning models for remote measurement of psoriasis and psoriatic arthritis: a proof-of-concept study.

OBJECTIVE: Psoricatic disease remains underdiagnosed and undertreated. We developed and validated a suite of novel, smartphone sensor-based assessments that can be self-administered to measure cutaneous and musculoskeletal signs and symptoms of psoriatic disease. METHODS: Participants with psoriasis, psoriatic arthritis, or healthy controls were recruited between June 5, 2019, and November 10, 2021, at two academic medical centers. Concordance and accuracy of digital measures and image-based machine learning models were compared to their analogous clinical measures from trained rheumatologists and dermatologists. RESULTS: Of 104 study participants, 51 (49%) were female and 53 (51%) were male, with a mean age of 42.3 years (SD: 12.6). Seventy-nine (76%) participants had psoriatic arthritis, 16 (15.4%) had psoriasis and 9 (8.7%) were healthy controls. Digital patient assessment of percent body surface area (BSA) affected with psoriasis demonstrated very strong concordance (CCC = 0.94, [95%CI = 0.91-0.96]) with physician-assessed BSA. The in-clinic and remote target-lesion Physician Global Assessments showed fair to moderate concordance (CCCerythema=0.72 [0.59-0.85]; CCCinduration=0.72 [0.62-0.82]; CCCscaling=0.60 [0.48-0.72]). Machine learning models of hand photos taken by patients accurately identified clinically-diagnosed nail psoriasis with an accuracy of 0.76. The Digital Jar Open assessment categorized physician-assessed upper extremity involvement, considering joint tenderness or enthesitis (AUROC = 0.68 (0.47-0.85)). CONCLUSION: The Psorcast digital assessments achieved significant clinical validity, although they require further validation in larger cohorts before use in evidence-based medicine or clinical trial settings. The smartphone software and analysis pipelines from the Psorcast suite are open source and freely available.

Nail Amyloidoma: Two Case Reports of a New Entity.

Introduction: Amyloidosis is a group of diseases characterized by extracellular deposits of abnormal insoluble proteins in different tissues. Amyloidoma is a localized tumoral deposit of amyloid in the absence of systemic amyloidosis, and it has been described in different anatomic sites. We report two cases of amyloidoma in the nail unit and provide insights into this recently described entity. Case Presentation: Both cases presented as an asymptomatic, slowly growing nodule underneath the distal nail bed of a toe with associated onycholysis. Histopathology was characterized in both patients by the presence of deposits of Congo red-positive, homogeneous, amorphous, and eosinophilic material within the dermis and subcutaneous tissue admixed with aggregates of plasma cells. In both cases, an extensive workup excluded systemic amyloidosis. Treatment was based on local excision, and no local recurrence or progression to systemic amyloidosis was observed at 1 year of follow-up. Conclusion: These are the first reports of amyloidomas of the nail unit. The clinical and histopathological presentations parallel those of an amyloidoma affecting the skin. Local excision seems to be an efficient treatment modality, but long-term follow-up is warranted in order to exclude recurrence, an associated marginal B-cell lymphoma, or progression to systemic amyloid L amyloidosis.

A clinicopathological description of COVID-19-induced chilblains (COVID-toes) correlated with a published literature review.

BACKGROUND: The abundance of publications of COVID-19-induced chilblains has resulted in a confusing situation. METHODS: This is a prospective single-institution study from 15 March to 13 May 2020. Thirty-two patients received PCR nasopharyngeal swabs. Of these, 28 patients had a thoracic CT-scan, 31 patients had blood and urine examinations, 24 patients had skin biopsies including immunohistochemical and direct immunofluorescence studies, and four patients had electron microscopy. RESULTS: COVID-19-induced chilblains are clinically and histopathologically identical to chilblains from other causes. Although intravascular thrombi are sometimes observed, no patient had a systemic coagulopathy or severe clinical course. The exhaustive clinical, radiological, and laboratory work-up in this study ruled-out other primary and secondary causes. Electron microscopy revealed rare, probable viral particles whose core and spikes measured from 120 to 133 nm within endothelium and eccrine glands in two cases. CONCLUSION: This study provides further clinicopathologic evidence of COVID-19-related chilblains. Negative PCR and antibody tests do not rule-out infection. Chilblains represent a good prognosis, occurring later in the disease course. No systemic coagulopathy was identified in any patient. Patients presenting with acral lesions should be isolated, and chilblains should be distinguished from thrombotic lesions (livedo racemosa, retiform purpura, or ischemic acral necrosis).

Cutaneous lymphocytic thrombophilic (macular) arteritis.

Macular arteritis (MA) has a striking discordance between the clinical presentation of hyperpigmented macules and the histopathologic findings of a lymphocytic arteritis with intraluminal hyalinized fibrin ring and thrombosis. It has been proposed that MA represents the chronic, indolent, lymphocytic form of the neutrophil-predominant cutaneous polyarteritis nodosa. MA usually affects middle-aged women asymptomatically on the legs. There is also a slightly more severe variant with more infiltrated plaques and livedo racemosa, termed lymphocytic thrombophilic arteritis. MA and lymphocytic thrombophilic arteritis have similar histologic features, both with a largely intact vascular elastic lamina, despite the abundant fibrin and endarteritis obliterans. There is no evidence for progression from MA to lymphocytic thrombophilic arteritis to cutaneous polyarteritis nodosa, and aggressive therapy should be avoided in MA, given the indolent, benign disease course.

Histologic Patterns and Clues to Autoinflammatory Diseases in Children: What a Cutaneous Biopsy Can Tell Us.

Autoinflammation is defined by aberrant, antigen-independent activation of the innate immune signaling pathways. This leads to increased, pro-inflammatory cytokine expression and subsequent inflammation. In contrast, autoimmune and allergic diseases are antigen-directed immune responses from activation of the adaptive immune system. The innate and adaptive immune signaling pathways are closely interconnected. The group of 'complex multigenic diseases' are a result of mutual dysregulation of both the autoinflammatory and autoimmune physiologic components. In contrast, monogenic autoinflammatory syndromes (MAIS) result from single mutations and are exclusively autoinflammatory in their pathogenesis. Studying the clinical and histopathological findings for the various MAIS explains the phenotypical correlates of their specific mutations. This review aims to group the histopathologic clues for autoinflammation into three recognizable patterns. The presence of these histologic patterns in a pediatric patient with recurrent fevers and systemic inflammation should raise suspicion of an autoinflammatory component in MAIS, or, more frequently, in a complex multigenic disease. The three major histopathological patterns seen in autoinflammation are as follows: (i) the 'neutrophilic' pattern, seen in urticarial neutrophilic dermatosis, pustular psoriasis, aseptic neutrophilic folliculitis, and Sweet's syndrome; (ii) the 'vasculitic' pattern seen in small vessel-vasculitis (including hypersensitivity/leukocytoclastic vasculitis, thrombosing microangiopathy and lymphocytic vasculitis), and intermediate-sized vessel vasculitis, mimicking polyarteritis nodosa; and (iii) the 'granulomatous' pattern. Beyond these three patterns, there are additional histopathologic clues, which are detailed below. It is important for a dermatopathologist to recognize the patterns of autoinflammation, so that a diagnosis of MAIS or complex multigenic diseases may be obtained. Finally, careful histopathologic analyses could contribute to a better understanding of the various clinical manifestations of autoinflammation.

Clinicopathologic and immunophenotypic characterization of lichen planopilaris and central centrifugal cicatricial alopecia: A comparative study of 51 cases.

BACKGROUND: The purpose of the study was to compare the histopathologic and immunophenotypic features of central centrifugal cicatricial alopecia (CCCA) and lichen planopilaris (LPP) to better characterize and differentiate these two clinical entities. CCCA remains an ill-defined and still-unsettled histologic entity and many hair loss experts regard CCCA to be histologically indistinguishable from LPP. Given the overlapping histologic features of these two lymphocyte-predominant cicatricial alopecias, and the lack of consensus regarding the significance of proposed distinctions, dermatopathologists face difficulty in providing clinicians and patients certainty with a definitive diagnosis of CCCA vs LPP. METHODS: We performed a retrospective review of 51 scalp biopsies of patients with either the clinical diagnosis of CCCA (27 cases) or LPP (24 cases). Clinical information, histologic features of hematoxylin-eosin-stained sections, and a panel of immunohistochemical markers were evaluated on scalp biopsies. Tested parameters were quantified, and statistical analysis was performed. RESULTS: Our study found no differences on either histologic assessment or immunophenotypic characterization between cases of classic LPP and CCCA. CONCLUSION: The conclusion of this study is that the inflammatory infiltrates in CCCA and LPP are not only histologically similar but also immunophenotypically indistinguishable.

Bullous Lupus Under Nivolumab Treatment for Lung Cancer: A Case Report With Systematic Literature Review.

BACKGROUND: Various immune-related adverse events (irAEs) have been reported to be associated with the use of immune checkpoint inhibitors. We report a case of a patient with lung cancer treated with nivolumab who developed a bullous eruption and give a systematic review of the literature on irAEs in patients treated with immune checkpoint inhibitors for lung cancer. CASE REPORT: A patient with lung adenocarcinoma developed a non-specific skin lesion at the time of his cancer diagnosis followed by flare episodes until the eighth cycle of nivolumab, when he developed a bullous lupus. As the first eruption had started a few months after his cancer diagnosis and was exacerbated during immunotherapy, a paraneoplastic origin is discussed. Since the patient also presented with flares under nivolumab, we reviewed reported irAEs. No bullous lupus was found but to date, 33 cases of paraneoplastic lupus and two of lupus erythematosus have been reported. CONCLUSION: To our knowledge, this is the first description of a bullous lupus exacerbated by nivolumab.

Primary scalp alopecia: new histopathological tools, new concepts and a practical guide to diagnosis.

The diagnosis of primary scalp alopecia remains one of the most challenging fields in dermatopathology. In this review, we would like to connect the established classification of primary alopecia into scarring (cicatricial) and non-scarring (non-cicatricial) with current concepts. We introduce a simplified pathway for the diagnosis of the most common causes of alopecia, including a discussion of tissue processing techniques and use of immunohistochemistry.