Updates in cutaneous manifestations of systemic vasculitis.

PURPOSE OF REVIEW: The main purpose of this review is to present newly reported cutaneous manifestations of systemic vasculitis, updates in investigations to verify systemic involvement in cases with cutaneous vasculitis and new therapeutic guidelines. The spectrum of COVID-19-related vasculitis is also covered. RECENT FINDINGS: Only a few reports highlighted new cutaneous presentations or associations with some systemic vasculitic entities. For example, the association of inflammatory disorders with Takayasu arteritis, the importance of considering Kawasaki disease in febrile children with erythema nodosum, the development of necrotic ulcers on fingers and toes in Behçet's disease and the possible presence of polyarteritis nodosa-like pathological features in vulvar ulcers of Behçet's disease. New attempts to classify cutaneous manifestations of giant cell arteritis (GCA) and antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and the diagnostic investigations for cutaneous vasculitis cases to verify systemic involvement are discussed. Treatment of systemic vasculitis with cutaneous vasculitis should be tailored according to disease status. A plethora of reports in the past 2 years focused on the broad spectrum of COVID-19 vasculitic manifestations. SUMMARY: Although newly reported cutaneous manifestations of systemic vasculitis are relatively uncommon, the plethora of reports in the past 2 years on COVID-19 vasculitis necessitates the expansion of the classification of vasculitis associated with probable cause to include severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2) vasculitis.

Hypopigmented lesions in pityriasis lichenoides chronica patients: Are they only post-inflammatory hypopigmentation?

BACKGROUND/OBJECTIVES: Pityriasis lichenoides chronica (PLC) lesions are reported to subside with post-inflammatory hypopigmentation (PIH); hence, the most widely perceived nature of hypopigmented macules in PLC is PIH. However, to the best of our knowledge, no studies describing histopathological findings in these lesions are reported in literature. The aim of this study is to evaluate the hypopigmented lesions encountered in PLC patients and to shed light on their histopathological features. METHODS: A cross-sectional observational study included twenty-one patients with PLC recruited in a period of twelve months. Clinical characteristics of each patient were collected. A skin biopsy from hypopigmented lesions whenever present was taken and assessed with routine haematoxylin and eosin stain. RESULTS: Seventeen patients (81%) were less than 13 years old. Most patients (85.7%) demonstrated diffuse distribution of lesions. Hypopigmented lesions were present on the face in 12 (57.14%) patients. Histopathologically, hypopigmented lesions showed features of post-inflammatory hypopigmentation in 19% of patients, residual PLC in 52.4% and active PLC 28.6% of patients. CONCLUSION: Hypopigmented lesions in PLC were noted mainly in younger ages, histopathologically they may show features of active or residual disease, beyond post-inflammatory hypopigmentation. Consequently active treatment for patients presenting predominantly with hypopigmented lesions could be required to control the disease.

Crystalglobulinemia: A Rare Presenting Manifestation of Multiple Myeloma.

ABSTRACT: Crystalglobulinemia (CG) is a rare disorder characterized by crystallization of monoclonal immunoglobulins in the microcirculation leading to multiorgan vascular thrombosis and ischemic injury. The main cause of CG is multiple myeloma. We report a case of a 52-year-old man who presented with widespread necrotizing plaques and ulcerations. A skin biopsy revealed eosinophilic rectangular-shaped crystals occluding the lumina of blood vessels with no associated features of vasculitis. The crystals were Periodic acid-Schiff stain positive. The findings were diagnostic of CG. Extensive work up lead to the discovery of multiple myeloma. Awareness of CG is important because it may be the first presenting manifestation of an underlying serious hematological malignancy.

Persistent Pixel Stamping Marks: a novel complication of fractional CO2 laser in scar treatment.

Fractional CO2 laser rejuvenation of scars offers a high safety profile. Laser marks usually disappear clinically within 1 week. The authors observed occasional persistence of the laser marks on the scar surface. The purpose of this study is to report the incidence and to describe the clinical, dermoscopic, and histological features of a novel observed complication of fractional CO2 laser scar rejuvenation "Persistent Pixel Stamping Marks (PPSM)".One hundred seventy-one cases were consecutively recruited from patients assigned for fractional CO2 laser scar rejuvenation. Patients who developed the phenomenon 1 month post laser session were recorded and subjected to clinical photography, dermoscopy, and optical coherence tomography (OCT) as well as a 4-mm punch biopsy from pixelated scars. The evolution of PPSM was followed up for 6 months. PPSM developed in 16 patients (9.4%), 15 of which were post burn hypertrophic scars. PPSM was significantly related to darker skin type, darker scar color, and longer scar duration. Histopathological findings included characteristic holes in stratum corneum and superficial dermis, thick collagen bundles perpendicular to the skin surface with loss of elastic tissue, focal interface changes, and triangular focus of fibroblastic proliferation. The marks disappeared in 5 and lasted in 11 patients. Their longevity was significantly related to longer dwell times and lower densities. PPSM represent miniature scarring at the sites of the microscopic thermal zones or a sign of their delayed healing. They tend to follow fractional CO2 laser resurfacing of hyperpigmented, long-standing burn scars. Longer dwell times and lower densities make them last longer.

Diagnostic accuracy of immunohistochemical markers in differentiation between basal cell carcinoma and trichoepithelioma in small biopsy specimens.

BACKGROUND: The distinction of trichoepithelioma from basal cell carcinoma in small superficial biopsies is important but often challenging. This has inspired many scientists to test the validity of immunohistochemical markers in the differential diagnosis. OBJECTIVES: To develop an immunohistochemical protocol that helps in differentiation between both trichoepithelioma (TE) and basal cell carcinoma (BCC) with higher sensitivity and specificity. METHODS: Using standard immunohistochemical techniques, we examined 10 TEs and 19 BCCs for the expression of CK19, Ki-67, androgen receptors (AR), CD10, and PHLDA1. RESULTS: Immunoreactivity of AR, Ki-67, and CD10 in tumor cells was significantly higher in BCC than TE with a diagnostic accuracy in BCC of 75.5%, 75.8%, and 79.3% respectively, whereas immunoreactivity of PHLDA1 in tumor cells and stromal CD10 was significantly higher in TE than BCC with a diagnostic accuracy in TE of 100% and 82.8%, respectively. In contrast, immunoreactivity for CK19 showed no statistically significant differences between both tumors. CONCLUSION: The analysis of CD10, Ki-67, and PHLDA1 can be used as a helpful immunohistochemical panel in the distinction between TE and BCC especially in small and superficial biopsies.

Hypopigmented Interface T-Cell Dyscrasia and Hypopigmented Mycosis Fungoides: A Comparative Study.

Hypopigmented interface T-cell dyscrasia (HITCD) is a distinct form of lymphoid dyscrasia that may progress to hypopigmented mycosis fungoides (HMF). We compared both diseases as regards their CD4/CD8 phenotype and expression of granzyme B and tumor necrosis factor-alpha (TNF-α) and how these are affected by narrow-band UVB (nb-UVB). The study included 11 patients with HITCD and 9 patients with HMF. They received nb-UVB thrice weekly until complete repigmentation or a maximum of 48 sessions. Pretreatment and posttreatment biopsies were stained using anti CD4, CD8, TNF-α, and granzyme B monoclonal antibodies. Epidermal lymphocytes were CD8 predominant in 54.5% and 66.7% of HITCD and HMF cases, respectively, whereas dermal lymphocytes were CD4 predominant in 63.6% and 66.7%, respectively. Significantly, more dermal infiltrate was encountered in HMF (P = 0.041). In both diseases, granzyme B was only expressed in the dermis, whereas TNF-α was expressed both in the epidermis and dermis. No difference existed as regards the number of sessions needed to achieve repigmentation or cumulative nb-UVB dose reached at end of study. (P > 0.05). Narrow-band UVB significantly reduced only the epidermal lymphocytes in both diseases (P ≤ 0.05) with their complete disappearance in 8 (72.7%) HITCD and 6 (66.7%) HMF cases. In both diseases, nb-UVB did not affect granzyme B or TNF-α expression (P > 0.05). In conclusion, both diseases share the same phenotype, with HITCD being a milder form of T-cell dysfunction. In both diseases, epidermal lymphocytes are mainly CD8-exhausted cells lacking cytotoxicity, whereas dermal cells are mostly reactive cells exerting antitumor cytotoxicity. Tumor necrosis factor-alpha mediates hypopigmentation in both diseases and prevents disease progression. Repigmentation after nb-UVB in both diseases occurs before and independently from disappearance of the dermal infiltrate.

Peripilar Sign in Androgenetic Alopecia: Does It Really Indicate Peripilar Infiltrate?

INTRODUCTION: Peripilar sign (PPS) is a trichoscopic sign that was first described in androgenetic alopecia (AGA) and is thought to reflect the presence of perifollicular infiltrate (PFI) in histopathology. OBJECTIVES: To study PPS in a cohort of patients with AGA and to assess its validity as a sign indicative of PFI. METHODS: One hundred patients with AGA (confirmed by trichoscopic examination) were recruited in this cross-sectional study. From those patients, frontal scalp biopsy was done for two subgroups, 22 patients with PPS and 23 patients without PPS. Both groups were compared as regards the presence of PFI. RESULTS: Peripilar sign was present in 50% of the 100 studied cases. No significant difference existed between those with and those without PPS as regards PFI. Peripilar sign was significantly more encountered in patients with skin type III (p=0.001). Its absence was significantly associated with lower interpretability of yellow dots (p<0.001) and their scores were significantly positively correlated (r=0.498, p<0.001). Peripilar sign was significantly associated with absent melanophages histopathologically (p=0.011). CONCLUSION: Peripilar sign as a trichoscopic sign in AGA does not reflect PFI. It represents a dark color more encountered in patients with lighter skin types. This can be explained by the increased contrast between the dark PPS and the lighter surrounding skin in lighter skin types. Further studies using melanocyte markers and Masson Fontana's stain are needed to further verify the cause of this peri-follicular dark color.