We report a case of severe subacute cutaneous lupus erythematosus (SCLE) in a patient with Whipple's disease involving the gastrointestinal and cardiac systems and chronic hepatitis B with undetectable viral load. Cutaneous lesions consistent with SCLE developed shortly after the diagnosis of Whipple's disease, with extensive involvement of the trunk and limbs and marked photosensitivity. Histopathology revealed interface dermatitis. Direct immunofluorescence on lesional skin showed linear fibrinogen and discontinuous granular IgM deposits at the dermo-epidermal junction. Autoimmune testing demonstrated antinuclear antibody > 1:320 with a nuclear speckled and multiple nuclear dots pattern, along with anti-SSA (Ro) and anti-sp100 positivity. The patient was treated with doxycycline, high-dose hydroxychloroquine and prednisone, resulting in significant clinical improvement within 1 month.

Cutaneous lupus erythematosus (CLE) is a complex inflammatory skin disease that presents either in isolation or as a frequent manifestation of systemic lupus erythematosus (SLE). CLE subtypes show clinical heterogeneity and varying associations with SLE. Histologically, CLE is characterized by interface dermatitis, a reaction pattern that involves immune-cell infiltration of the dermo-epidermal junction. In-depth characterization of both non-lesional and lesional lupus skin has reshaped our understanding of pathogenesis. Non-lesional and lesional lupus skin exhibits early and chronic upregulation of type I interferons, which drive photosensitivity, myeloid-cell recruitment and amplification of cytokine responses in both immune and non-immune cells. This detailed understanding of CLE biology has enabled the development of targeted therapies. Ongoing research to identify key pathogenic mechanisms will create opportunities for prevention of CLE and CLE-to-SLE transition.

Discoid lupus erythematosus (DLE) is the most common variant of cutaneous lupus. Histopathology remains the gold standard for diagnosis, but it carries a risk of scarring in a disease already prone to cicatricial outcomes. Additionally, diagnostic delays may occur due to variable processing times, particularly in challenging cases. Line-field confocal optical coherence tomography (LC-OCT) is a novel non-invasive imaging technique offering high-resolution, histology-like features. This study evaluates its diagnostic accuracy in DLE by assessing concordance with histopathology. A cross-sectional study enrolled histologically confirmed DLE from three tertiary referral hospitals. Eleven histological criteria were assessed using LC-OCT and subsequently compared to histopathology. Concordance was evaluated using Cohen's Kappa coefficient (K), with McNemar's test applied to detect significant differences (α = 0.05). Twenty-eight patients with DLE participated in the study. LC-OCT demonstrated strong agreement with histopathology in key diagnostic features of DLE. Near-perfect concordance (K = 1, 100% agreement) was observed for interface dermatitis, dermal vessel dilation, epidermal atrophy, and incontinentia pigmenti. Substantial agreement was found for epidermal disarray (K = 0.85), spongiosis (K = 0.70), necrotic keratinocytes (K = 0.70), and infundibular dilation (K = 0.79). Overall, LC-OCT achieved a Cohen's Kappa of 0.74 with 87.66% concordance, and no statistically significant differences were observed between the two methods (McNemar p = 0.627). LC-OCT is a rapid, effective, and non-invasive diagnostic tool for DLE, demonstrating strong concordance with histopathology and potential for early diagnosis and clinical implementation.

Immune checkpoint inhibitors (ICIs) can trigger severe cutaneous adverse reactions that mimic Stevens-Johnson syndrome/toxic epidermal necrolysis. Reports describe a wide spectrum of cutaneous reactions, including epidermal necrosis, raising questions about whether this represents a distinct clinicopathologic entity. To review the literature on ICI-related epidermal necrosis (ICIREN), examining terminology, histopathologic features, clinical course, pathophysiology, the pathologist's role in diagnosis, and implications for management. A systematic literature search of PubMed and relevant conference proceedings was conducted. Key sources include case series, retrospective reviews, and mechanistic studies detailing ICIREN. ICIs have transformed cancer therapy but are associated with a spectrum of immune-related adverse events, notably cutaneous toxicities. Among the most severe is ICIREN, a reaction that can clinically resemble Stevens-Johnson syndrome and toxic epidermal necrolysis but may follow a distinct, more indolent course. Emerging terminology, including progressive immunotherapy-related mucocutaneous eruption, reflects growing recognition that not all cases fit the paradigm of classic drug-induced Stevens-Johnson syndrome/toxic epidermal necrolysis. ICIREN often presents with delayed onset, variable progression, limited mucosal involvement, and distinct histopathologic features such as lichenoid interface dermatitis and adnexal involvement. Understanding these differences is crucial, as early recognition and management may allow patients to safely continue ICI therapy. The underlying pathogenesis involves checkpoint blockade-driven T-cell activation with potential amplification by additional drug exposures. This review aims to equip pathologists and clinicians with a structured approach to the diagnosis, reporting, and multidisciplinary management of ICIREN, emphasizing the need for clinicopathologic correlation to optimize patient outcomes.

Dermatologic adverse effects with elranatamab mimicking talquetamab

Complete donor chimerism following deceased-donor liver transplant in an adolescent with hepatitis-associated severe aplastic anemia

Abstract Introduction Dermatomyositis rashes in Afro-Caribbean individuals can present differently in comparison to individuals with lighter skin tones. Dyschromia, changes in skin colour, can be the presenting feature of dermatomyositis rashes in Afro-Caribbean cohorts. We present a case of an Afro-Caribbean patient who presented with dyschromia. Case description A 45-year-old Afro-Caribbean woman presented with three year history of progressive skin hyperpigmentation affecting her face, forehead, neck and subsequently upper limbs, torso and lower limbs. She is an accountant who does not smoke, drink nor use illicit drugs. She described a preceding itching sensation followed by a burning sensation of her hyperpigmented skin. She denies photosensitivity. She was reviewed by dermatology in the private sector. The first skin biopsy in 2022 showed lichen planus pigmentosus (LPP). When the skin hyperpigmentation progressed, a second skin biopsy in 2024 demonstrated post-inflammation hyperpigmentation. She did not respond to topical calcineurin inhibitor. She has strongly positive ANA. ENA, dsDNA and complements, however, are normal. There are no features to suggest systemic sclerosis, especially Raynaud’s phenomenon. When she was first reviewed by rheumatology, she had dyschromia with hyperpigmentation in pathognomonic locations (images 1-3). She reported a six month history of progressive proximal weakness without bulbar or respiratory involvement. CK was elevated at 1610 U/L with MMT8 score of 133/150. She was found to have strongly positive Mi-2 antibodies. Electromyography was consistent with inflammatory myopathy with fibrillation potentials. MRI demonstrated oedema affecting adductor muscles, gluteal muscles and, to a milder degree, anterior thigh muscles. Muscle biopsy was consistent with inflammatory myositis in the pattern of dermatomyositis with upregulation of HLA Class 1. CT scan of chest, abdomen and pelvis did not show interstitial lung disease but revealed a breast lesion which upon further investigations was benign. She responded well to corticosteroid therapy and was promptly commenced on dual treatment of mycophenolate mofetil and hydroxychloroquine. Her skin is improving with less itching and less dyschromia. MMT8 score improved to 148/150. Discussion Classical dermatomyositis rashes are widely known violaceous heliotrope rashes, Gottron’s papules, V and shawl signs. In an Afro-Caribbean cohort, dermatomyositis rashes can be atypical, leading to delayed or missed diagnoses as described in this case. In African descendants, facial oedema is generally predominant and Gottron’s papules are often hypochromic. In others, the papules, V and shawl signs can appear darker with varying shades of pigmentation. Nailfold abnormalities can be subtle and easier to miss. Dyschromia is the prominent cutaneous features in a case series of 14 myositis patients of black individuals. Skin biopsies in dermatomyositis typically show a combination of vacuolar interface dermatitis, increased dermal mucin and perivascular inflammation. They may also show dyskeratosis and superficial dermal vascular dilatation. None of these were present in the skin biopsies for our patient but the absence clearly does not exclude dermatomyositis. LPP is a chronic disease characterised by hyperpigmented lichenoid lesions in intertriginous and sun-exposed skin of unknown aetiology. LPP and dermatomyositis are distinct diseases but cases of overlap syndrome have been documented, such as in our patient. Key learning points • Dermatomyositis rashes in an Afro-Caribbean cohort can manifest in an atypical pattern and potentially lead to delayed or missed diagnoses alongside increased morbidity and mortality. • The rashes may appear lighter in colour but, in other cases, they can appear darker with varying shades of pigmentation. • Dyschromia can be the prominent feature. • LPP and dermatomyositis are distinct diseases but cases of overlap syndrome have been documented. • Knowledge of clinical appearances of dermatomyositis rashes in darker skin is essential in reducing racial disparity in practice and facilitating early diagnosis and management.

Dermatomyositis is an autoimmune disease characterized by heterogeneous clinical and histopathologic features. Myositis-specific antibodies and myositis-associated antibodies have been linked to distinct clinical phenotypes, but their relationship with specific histopathologic features is unclear. This study aimed to characterize cutaneous histologic patterns in dermatomyositis patients with known autoantibody profiles. We conducted a retrospective review of patients with positive myositis-specific antibody/myositis-associated antibody serology, a clinical diagnosis of dermatomyositis, and skin biopsies of lesional dermatomyositis-affected skin. Clinical data were extracted from medical records, and histopathologic features were recorded after masked review by 3 subspecialized dermatopathologists. Associations between antibody subtypes and histopathologic features were analyzed using Fisher exact test. The cohort comprised 30 patients who underwent 47 biopsies between 2009 and 2024. The most prevalent features were vacuolar interface dermatitis (70.4%), dermal mucin (71.1%), and mild superficial perivascular inflammation (81.5%). Perivascular inflammation without associated interface dermatitis was associated with nuclear matrix protein 2 positivity (P < 0.01). Transcriptional intermediary factor 1γ-positive biopsies were less likely to demonstrate dermal mucin (P < 0.01). No significant associations were found between antibodies and adnexal inflammation or the type of interface dermatitis (vacuolar or lichenoid). Variability in skin biopsy findings from dermatomyositis patients with specific autoantibodies is limited. Perivascular inflammation without interface change and an absence of dermal mucin may be more common in patients with nuclear matrix protein 2 and TIF1γ autoantibodies, respectively. These observations may aid diagnosis in cases with atypical histologic features.

Background. The spectrum of cutaneous adverse drug reactions (ADR) caused by antitubercular drugs is broad and includes Stevens‑Johnson syndrome, DRESS syndrome, and generalized lichenoid drug eruption (LDE). LDE accounts for less than 10% of all anti‑tubercular drug-induced cutaneous ADR. It is characterized by erythematous, violaceous papules resembling lichen planus. This can pose challenges regarding patient compliance and treatment effectiveness. Case report. The present case study describe 5 patients who developed lichenoid drug eruptions secondary to antitubercular therapy (ATT) at our outpatient department between March 2024 and February 2025. All cases occurred in women, suggesting a possible gender-specific susceptibility that warrants further investigation. Skin biopsies revealed histopathological features of lichenoid interface dermatitis, including eosinophils and necrotic keratinocytes. A systematic drug rechallenge identified pyrazinamide as the culprit in both tested patients, consistent with recent evidence indicating pyrazinamide as the most common cause of positive ATT rechallenge reactions. Conclusion. The exclusive female involvement and the definitive identification of pyrazinamide as the offending agent provide valuable clinical insights for the monitoring and management of ATT-induced LDE. Current treatment strategies emphasize continuation of essential ATT, whenever feasible, in combination with topical corticosteroids and antihistamines, while systematic rechallenge remains the gold standard for identifying causative drugs. Further research is needed to identify potential biomarkers that could enable earlier detection and management of ATT-induced LDE.

Overlap (SCARs) severe cutaneous adverse drug reactions, are defined as cases that fulfill diagnostic criterio for at least two of these drug-associated reactions, according to scoring systems. We present a case of an overlapping SCAR. A 53-year-old female was diagnosed with diabetes and was being treated with metformin and linagliptin, and with high blood pressure with nifedipine. Secondary to an isolated seizure, she was treated with phenytoin, 5 weeks later, she presented with erythema in the chest region accompanied by pruritus that spread to the abdomen. Treatment was initiated with antihistamines, with poor improvement, progressing to generalized erythema and fever. Upon admission, she presented with generalized polymorphic skin lesions of a maculopapular rash and bullous lesions on the forearms, as well as pustular lesions on the face. Laboratory findings: Leukocytosis with neutrophilia (67%), eosinophilia =3,880/mm3, and acute kidney injury. Biopsy: Chronic interface dermatitis, superficial perivasculitis, and eosinophilia. According to RegiSCAR scoring system with 4 points and the EuroSCAR score with 6 points, both considered probable The patient began steroid therapy with methylprednisolone at 1.5 mg/kg for 3 days, followed by reduced doses of prednisone. The patient presented a severe cutaneous adverse reaction 5 weeks after starting phenytoin, which showed overlap according to the scales. Secondary to the ambiguities among SCARs, confirmed cases of overlap are rare. In the acute stage of the disease, early identification of SCARs can be difficult due to overlapping features.

Diagnosing a case of patchy alopecia in the setting of lupus erythematosus (LE) can be clinically challenging. Of the various causes of LE-specific alopecias, lupus panniculitis of the scalp is rarely reported. A 40-year-old woman presented with a nonscarring patch of alopecia over the scalp. Trichoscopy showed multiple follicular plugging, multiple thin and dystrophic hair shafts, empty follicles, and regularly distributed pinpoint white dots within the lesion. The clinical diagnoses of alopecia areata or early discoid LE were considered. However, the histopathological examination of the scalp biopsy showed typical hyaline-type fat necrosis of the subcutis along with moderate perivascular and perifollicular inflammatory infiltrate without any interface dermatitis. On direct immunofluorescence, staining for IgG, IgA, IgM, and C3 was negative. A diagnosis of lupus panniculitis of the scalp, presenting as patchy nonscarring alopecia, was rendered. Treatment with oral prednisolone and methotrexate led to complete recovery of alopecia. In conclusion, we report a rare case of lupus panniculitis of the scalp and discuss its differential diagnosis in the setting of LE.

Cutaneous lupus erythematosus (CLE) is a chronic inflammatory skin disease with various clinical subtypes. Although its pathogenesis is not yet fully understood, T-cell-mediated autoimmunity and elevated levels of type I interferons (IFNs) are two major factors that contribute to the development of cutaneous lesions. Type I IFNs transduce their signal via tyrosine kinase 2 (TYK2). To investigate the impact of TYK2 signalling in preclinical models of CLE. CLE skin biopsies were investigated by RNA sequencing (RNAseq) and immunohistochemistry. T cells isolated from CLE skin biopsies (lesional T cells) were restimulated with anti-CD3/anti-CD28 and cytokine release was quantified by enzyme-linked immunosorbent assay and Luminex®. Primary human keratinocytes and three-dimensional skin models were stimulated with IFN-α or lesional T-cell supernatant in the presence or absence of the TYK2 inhibitor deucravacitinib, followed by RNAseq. Skin biopsies from patients with different CLE subtypes were treated ex vivo with deucravacitinib followed by real-time quantitative polymerase chain reaction. Bulk RNAseq revealed a strong correlation between TYK2 and interface dermatitis, a histological hallmark of CLE. Immunohistochemistry confirmed a high abundance of TYK2 in different CLE subtypes. Inhibiting TYK2 reduced inflammation and normalized epidermal impairments in primary human keratinocytes, reconstructed human epidermis and CLE T cells. Ex vivo TYK2 inhibition in CLE skin biopsies reduced IFN response and necroptosis-related gene expression. Finally, four patients with different therapy-refractory subtypes of CLE (acute, subacute, chronic discoid, chilblain CLE) were successfully treated with deucravacitinib. IFN-α and T-cell-derived cytokines both contribute to skin inflammation in CLE. TYK2 inhibition is a promising approach for different subtypes of CLE as it controls inflammation in various preclinical models and patients with CLE who are refractory to treatment.

BackgroundAlthough immune checkpoint inhibitors (ICIs) are efficacious, they often cause immune-related adverse events (irAEs), most commonly cutaneous irAEs (CirAEs). The mechanisms underlying CirAEs remain unclear.MethodsAttempting to better understand their mechanisms and histology we conducted a prospective study of 15 patients with advanced cancers treated with ICIs who developed grade 2 or higher CirAEs. Clinical and histologic characterization of biopsy specimens of CirAEs was performed. Histologic analysis of patient biopsy specimens were subdivided by epidermal reaction patterns that included spongiotic, lichenoid, and interface dermatitis patterns. A targeted RNA expression assay was used to identify immune markers in CirAE lesions and adjacent unaffected skin samples.ConclusionsCompared with adjacent unaffected skin, CirAE lesions had significantly upregulated THY1 (CD90) and increased M2 macrophages (adjusted p<0.05). Our findings suggest that CirAEs exhibit diverse histologic patterns that may mimic autoimmune skin diseases. The lack of distinct biomarker signatures may indicate complex and heterogeneous mechanisms underlying CirAEs; however, the upregulation of THY1 and elevated numbers of M2 macrophages in CirAE lesions suggest THY1 and M2 macrophages may be involved in the pathogenesis of these toxic effects. Further investigation to elucidate the molecular determinants of CirAEs and develop targeted therapeutic strategies is warranted.

Abstract Systemic lupus erythematosus (SLE) is an autoimmune disorder that occurring due to triggers such as ultraviolet radiation and drugs, involving both innate and adaptive immune systems. It is usually treated with topical and systemic corticosteroids, antimalarials such as hydroxychloroquine (HCQ) and photoprotection. Vitiligo is also an autoimmune disorder of T-cell driven melanocyte destruction due to genetic predisposition, oxidative stress and drugs. Here, we describe a case of SLE who developed vitiligo over cutaneous lupus lesions after long-term HCQ therapy. A 25-year-old female presented with bilaterally symmetrical erythematous scaly plaques over upper and lower limbs with a malar rash for 1 year with a history of fever, arthralgia, myalgia and oral ulcer. The anti-nuclear antibody titre was &gt;1:160. The haemoglobin value was 8.9 g/dl. Biopsy of the lesion showed perivascular and periappendageal lymphocytic infiltrates, interface dermatitis and vacuolar degeneration of basal cells. She was diagnosed as a case of SLE with papulosquamous type subacute cutaneous lupus lesion and started on oral HCQ 200 mg twice daily. After 2 years, she developed depigmented patches over the dorsum of hands and feet which was diagnosed as vitiligo clinically and by dermoscopy. Association of lupus erythematosus and vitiligo has been described in literature based on theory of immunocompromised cutaneous district and shared inflammatory pathways involving plasmacytoid dendritic cells. Moreover, long-term HCQ can contribute to depigmentation as it interferes with melanogenesis. Investigations are needed to rule out multiple autoimmune syndrome and autoimmune polyglandular syndrome. In this case, phototherapy should be avoided as a treatment modality for vitiligo, as it can aggravate lupus.

Abstract A 76-year-old woman was initially admitted for dizziness and progressive hand tremors. She incidentally presented with a 3-week history of an annular eczematous eruption, primarily affecting her arms, legs and buttock, but sparing the face. The rash was well demarcated and erythematous and had peripheral scaling, resembling psoriasis. She had a background history of psoriasis, eczema, epilepsy, ischaemic heart disease and previous alcohol excess. Her psoriasis had previously been treated with topical coal tar and remained stable afterwards. The differential diagnosis included subacute cutaneous lupus erythematosus (SCLE), psoriasis, tinea, drug reaction and paraneoplastic conditions. Initially, the rash showed some improvement with topical corticosteroids but it flared upon discontinuation. A computed tomography scan of the thorax, abdomen and pelvis ruled out any paraneoplastic cause. Magnetic resonance imaging of the brain revealed only alcohol-related cerebellar degenerative changes, and her routine biochemical blood tests were unremarkable. Skin scrapings were negative for fungal elements. A skin biopsy revealed hyperkeratosis, acanthosis and moderate spongiosis, suggesting a spongiotic dermatitis. The patient was treated for psoriasis with ustekinumab; however, this worsened her existing rash, with the skin lesions taking on an annular, polycyclic appearance with desquamation. She was treated with potent topical corticosteroids, which improved her symptoms but failed to resolve the rash completely. This change prompted a reconsideration of the diagnosis, and differentials included SCLE, tinea, pityriasis rubra pilaris, necrolytic migratory erythema and acrodermatitis enteropathica. Two months later, a second skin biopsy was performed, revealing hyperkeratosis, parakeratosis, interface dermatitis and a perivascular inflammatory infiltrate in the superficial dermis. Periodic acid–Schiff stain was negative for fungal organisms. Further blood tests showed a normal glucagon level; however, her zinc levels were deficient at 4.4 μmol L−1 (normal range 11–18 μmol L−1). Given her history of alcohol excess and acquired nutritional deficiency, a diagnosis of acrodermatitis enteropathica was made. Her ustekinumab was stopped, and she was commenced on high-dose zinc supplementation 50 mg three times daily. Within 4 weeks the patient showed significant improvement in her skin lesions with 90% clearance. We present a case of acrodermatitis enteropathica in an adult patient with acquired zinc deficiency masking as psoriasis. This case highlights an important differential to consider in patients with suspected psoriasis not responding to conventional treatments.

Abstract Cemiplimab is a highly selective humanized monoclonal antibody targeting programmed cell death protein-1 (PD-1). It is approved for locally advanced and metastatic cutaneous squamous cell carcinoma (cSCC). It is associated with a wide range of cutaneous immune-related adverse effects (irAEs) including immunobullous, lichenoid and eczematous reactions. We present an unusual manifestation of cemiplimab skin toxicity undescribed previously – ‘cemiplimab toes’. A 47-year-old Indonesian woman started cemiplimab in October 2023 for primary cSCC in the external auditory meatus, which metastasized to parotid and cervical lymph nodes and bone. Despite extensive surgery and radiotherapy the tumour recurred locally and was inoperable. Within two to three cycles of cemiplimab, she noticed itching of her toes, which recurred with subsequent cycles of cemiplimab. However, by cycle 6, she reported the onset of marked periungual redness, swelling, itching and pain in all 10 toes, making mobilizing difficult. As pain was severe, the initial concern was of a vasculitic process and oncology started prednisolone 2 mg kg−1 per day (120 mg per day) and flucloxacillin, with symptoms improving rapidly. On dermatology review, all 10 toes demonstrated intense periungual redness, possible vesicles, and erosions gradually evolving into a more violaceous appearance with hyperkeratosis, paronychia-type changes and fissuring. Raynaud symptoms were absent, the fingers were unaffected, there were no rashes elsewhere and there was no mucosal involvement. Clinically it was difficult to distinguish between eczematous, psoriasiform, lichenoid, vasculitic, perniotic, autoimmune bullous, ischaemic and paraneoplastic processes. Bacterial swabs grew Staphylococcus aureus, and viral swabs and mycology were negative. Indirect immunofluorescence and autoimmune and vasculitis screen (including antinuclear antibodies, extended myositis panel, creatine phospho­kinase, complement, cryoglobulins and thrombophilia screen) were normal or negative. Incisional skin biopsy showed a predominantly spongiotic dermatitis with discrete epidermal psoriasiform change and no evidence of vasculitis, interface or lichenoid dermatitis or bullous processes. Direct immunofluorescence was negative. Although she responded well to oral steroids and suspending cemiplimab, her skin flared with subsequent cycles with prednisolone doses below 10 mg per day despite topical treatment with clobetasol propionate, tacrolimus and calcipotriol–betamethasone ointments, fludroxycortide tape, Fucibet cream and potassium permanganate soaks. Treatment that will allow continuation of cemiplimab while avoiding ongoing immunosuppression remains challenging. This dramatic localized skin irAE to a PD-1 checkpoint inhibitor involving only the toes has not been described previously. Clinically some features were reminiscent of ‘COVID toes’, but the underlying mechanism is unknown. This case of ‘cemiplimab toes’ is a striking reminder of the ever-evolving spectrum of cutaneous irAEs associated with immunotherapy and the challenges in diagnosing and managing these effectively to mitigate morbidity while continuing oncological treatment.

Abstract A 65-year-old White man developed violaceous, scaly, pruritic plaques on the umbilicus and lower back 12 weeks into adjuvant pembrolizumab therapy following nephrectomy for high-risk clear cell renal carcinoma. Initially thought to be psoriasis due to possible koebnerization on old scars, the rash expanded to involve the palms, thighs, buttocks, groin and penis. Diagnostic biopsies performed after dermatology review revealed hyperkeratosis, acanthosis with elongated rete ridges, vacuolar interface dermatitis, Civatte bodies and a bandlike lichenoid inflammatory infiltrate consistent with lichen planus. The rash resolved with oral and topical steroids and did not recur upon tapering, but pembrolizumab was discontinued. Skin reactions are among the most frequent immune-related adverse effects of checkpoint inhibitor immunotherapy across cancer types (Geisler AN, Phillips GS, Barrios DM et al. Immune checkpoint inhibitor-related dermatologic adverse events. J Am Acad Dermatol 2020; 83: 1255–68). Lichenoid reactions are one of the more common manifestations. However, checkpoint inhibitor-induced lichenoid reactions often present atypically, reflecting the diverse clinical patterns of immune dysregulation, and are thought to result from enhanced activity of T helper 1 and T helper 17 effector T cells. Lichen planus (LP) typically affects flexural and dorsal surfaces of the upper limbs, shins and lower back, with frequent oral mucosal involvement. Our case is notable for its atypical umbilical presentation. While Koebner phenomenon was considered, it was deemed unlikely as other scars remained unaffected. The programmed death-1 signalling pathway modulates cytokine production, including interferon-γ, interleukin-2, interleukin-17 and tumour necrosis factor-α. These are key mediators of immune dysregulation in LP and psoriasis, suggesting potential mechanistic overlap. Umbilical involvement in LP is exceedingly rare, with only three cases reported in the literature, including one instance of nivolumab-induced umbilical LP (Martos-Cabrera L, Lladó I, Fernández-Rico P, Butrón-Bris B, Rodríguez-Jiménez P. Umbilical lichen planus induced by nivolumab. An Bras Dermatol 2023; 98: 712–14). We describe a second case of checkpoint inhibitor-induced umbilical LP, adding to the limited but growing evidence of this uncommon manifestation. Checkpoint inhibitor therapy has revolutionized cancer treatment, but its immune-related side-effects require timely recognition and management to prevent severe outcomes. Increasing reports of atypical lichenoid reactions highlight the spectrum of these events. Our report adds evidence of umbilical and psoriasiform LP as a distinct clinical pattern, highlighting the importance of awareness among oncologists and dermatologists.

We report a 22-month-old boy with febrile ulceronecrotic Mucha-Habermann disease who presented with rapid progression of necrotic skin lesions and fever. The diagnosis was confirmed by histopathology, which revealed interface dermatitis, intraepidermal vesiculation, and erythrocyte extravasation. Immunohistochemistry revealed perivascular T-cell infiltration. Treatment with systemic corticosteroids, antibiotics, and antivirals achieved resolution. This case highlights diagnostic challenges and emphasizes the importance of integrating histopathology, immunohistochemistry, and prompt multimodal therapy.

BackgroundPhimosis is a frequent indication for pediatric outpatient referral. Pathological phimosis results from chronic inflammatory changes, often with lichenoid changes resulting in a hypopigmented indurated preputial plaque. Treatment of preputial lichen sclerosus is circumcision followed by long-term topical steroid application in histologically confirmed cases. Routine histopathologic examination of circumcision specimens is advisable to detect early cases of lichen sclerosus.Materials and methodsA retrospective chart review of children operated for pathological phimosis over a 32-month period was conducted. Demographic details, clinical symptomatology, histological findings, and outcomes at follow-up were collated and analyzed.ResultsOf the 30 patients enrolled in this study, the mean age of presentation was 9.6 years. Inability to retract the foreskin was seen in all patients, and preputial ballooning were seen in 20 (67%) patients. Biopsy was available in 25 patients, with all specimens demonstrating abnormal findings: lichen sclerosus (18; 72%), lichenoid dermatitis (4; 16%), and chronic non-specific inflammation (3; 12%). Meatal involvement was seen in four patients, with all improved with prolonged topical steroid therapy.ConclusionRecurrence of phimosis or failure despite topical steroid therapy is likely to represent pathological phimosis. Routine biopsy of all pathological phimosis specimens is recommended. Changes in interface dermatitis and lichenoid lymphocytic inflammation are the commonest findings on biopsy, and long-term steroids and regular follow-up are imperative.

Systemic lupus erythematosus (SLE) is a chronic, multi-organ autoimmune condition most commonly seen in young to middle-aged women. It carries with it a mortality rate two to three times higher than that of the general population and its prevalence is increasing. The pathogenesis is unknown but thought to be due to a combination of genetic, hormonal, and environmental factors leading to the production of autoantibodies, most notably antinuclear antibodies (ANA) and immune complex formation, resulting in dysfunctional cytokine expression. Symptoms associated with this condition vary greatly, from mild to life-threatening, which can lead to a delay in diagnosis. Cutaneous manifestations of SLE are common, but SLE-associated genital ulceration is very rare. Since the first case report in 1993 there have been five cases reported of vulval ulceration associated with SLE with only one documented case where it was a first presentation of SLE. A 25 year-old woman was referred to dermatology with a 3-month-history of recurrent vulval ulceration. Infectious etiology and malignancy were ruled out. She had a medical history of pernicious anemia but no family history of autoimmune conditions. On examination there were superficial ulcers over the labia minora, perineum, introitus, and anus and an erythematous plaque on her nose. The remainder of her examination was normal. Following initial review she developed an acute rash on sun-exposed sites. Investigations revealed positive ANA and anti-ribonucleoprotein antibodies. Punch biopsies were taken from her back and vulva revealing features of interface dermatitis. A diagnosis of SLE was made. Genital ulcers have been reported in patients with cutaneous lupus and a small number of patients with known SLE. However, we found only one other case where genital discomfort was the presenting complaint before diagnosis of SLE. Our case highlights the importance of considering a broad differential diagnosis for genital ulcers.