Hookworm Folliculitis: Report of Two Cases of Cutaneous Larva Migrans With Histologically Identified Follicular Involvement.

ABSTRACT: Cutaneous larva migrans (CLM) is an ectoparasitic infestation predominantly caused by nematodes, specifically Ancylostoma braziliense and Ancylostoma caninum, found in tropical and subtropical regions. Although follicular involvement by the parasite is a rare manifestation, with approximately 20 cases reported in the English literature, its pathogenesis remains underexplored. The present study reports 2 cases of CLM presenting with follicular involvement in patients with pruritic lesions following travel to subtropical areas. The first of them is a 32-year-old woman who developed an abdominal skin lesion subsequent to a trip to Thailand and the second is a 28-year-old woman who exhibited a knee lesion after a volunteer mission in Senegal. Histologic examination revealed characteristic features of CLM, such as nematode larvae traversing the hair follicle. The hookworm larvae were observed creating tunnels within the external root sheath. In addition, they were interfacing with the vitreous layer, sparing the perifollicular connective tissue sheath and the Henle layer, and approaching the vicinity of the hair bulb. The application of skin ultrasound to guide the biopsy facilitated the visualization and identification of the parasite within the follicle in the latter case. This study not only underscores follicular involvement in CLM but also provides insights into its anatomopathological presentation and spread through the hair follicle.

Pancreatic panniculitis revisited: A series of 34 patients.

BACKGROUND: Pancreatic panniculitis is a rare form of panniculitis generally associated with acute or chronic pancreatitis, and less frequently with pancreatic carcinoma. Clinically, it presents with subcutaneous nodules usually located in the lower extremities, however, it presents an almost pathognomonic histopathological finding with enzymatic fat necrosis in the adipose tissue. METHODS: In this retrospective case series of five hospitals, biopsy specimens of cutaneous lesions of pancreatic panniculitis were reviewed. Clinical information was obtained through medical records. RESULTS: A total of 34 cases were included, 23 women and 11 men, aged between 31 and 92 years. The most common associated pancreatic disease was acute pancreatitis (23 cases) and its main triggering cause was gallstones (17 cases). In two patients it was related to chronic pancreatitis and six cases were associated with malignancy. Histopathological findings were always the key to diagnosis. In the biopsies reviewed, mostly lobular panniculitis with the characteristic necrosis of the adipocytes was observed. In addition, nine of the cases presented with Splendore-Hoeppli phenomenon. CONCLUSIONS: We present the largest series of pancreatic panniculitis. Clinically, the female predominance and biliary lithiasis as the main cause of acute pancreatitis are to be emphasized. Histopathologically, a peripheral eosinophilic striated rim surrounding aggregates of ghost adipocytes consistent with Splendore-Hoeppli is an additional clue to its diagnosis.

AI-empowered cellular morphometric risk score improves prognostic stratification of cutaneous squamous cell carcinoma.

INTRODUCTION: Risk stratification of cutaneous squamous cell carcinoma (CSCC) is essential for managing patients. Artificial intelligence and machine learning might help stratify patients with CSCC by risk using more than solely clinical and histopathological factors. METHODS: A retrospective cohort of 104 CSCCs excised with clear margins was retrieved. Clinical and histopathological risk factors were evaluated. Hematoxylin and eosin-stained slides were scanned and analyzed by an algorithm based on the stacked predictive sparse decomposition technique. Cellular morphometric biomarkers (CMBs) were identified via machine learning and used to derive a cellular morphometric risk score (CMRS) that classified CSCC into clusters of differential prognosis. Concordance analysis, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated and compared with results obtained with the Brigham and Women's Hospital (BWH) staging system. The performance of the combination of the BWH staging system and the CMBs was also analyzed. RESULTS: There were no differences among CMRS groups in terms of clinical and histopathological risk factors and T-stage assignment, but there were significant differences in prognosis. Combining the CMRS with BWH staging systems increased distinctiveness and improved prognostic performance. C-indices were 0.92 for local recurrence and 0.91 for nodal metastasis when combining the two approaches. The NPV was 94.41% and 96.00%, the PPV was 36.36% and 41.67%, and accuracy reached 86.75% and 89.16% with the combined approach. CONCLUSION: CMRS is helpful for CSCC risk stratification beyond classic clinical and histopathological risk features. Combining the information from the CMRS and the BWH staging system offers outstanding prognostic performance for high-risk CSCC patients.

High-risk mucosal human papillomavirus-associated squamous cell carcinoma of the fingers presents distinctive clinicopathological characteristics and outcomes: a bicentric retrospective study.

BACKGROUND: High-risk mucosal human papillomavirus (HR-HPV) seems to play a role in cutaneous squamous cell carcinoma (cSCC), particularly in nail tumours, where genitodigital transmission has been suggested. The role of HR-HPV in nonungual cSCC of the finger needs to be clarified. AIM: To evaluate the prevalence, clinicopathological characteristics, surrogates and outcomes of HR-HPV in cSCC of the finger. METHODS: This was an observational bicentric study including patients with an excised in situ or invasive cSCC located on the finger. Differences in HR-HPV and non-HR-HPV tumours were evaluated. RESULTS: Forty-five patients (45 tumours) were included. HR-HPV was detected in 33% of cases (22% HPV type 16). The mean age was lower in patients with HR-HPV than in those with non-HR-HPV (62·4 vs. 81·1 years, P = 0·001). HR-HPV tumours were smaller (10 mm vs. 15 mm, P = 0·07) and more frequently intraepidermal (60% vs. 20%, P = 0·004). The absence of elastosis (P = 0·030) and inflammation (P = 0·026) and the presence of basaloid morphology (P = 0·003) were surrogates of HR-HPV detection. Mean p16 positivity was 61% in HR-HPV and 36% in non-HR-HPV tumours (P = 0·061). Recurrence after surgery was more common in HR-HPV tumours (58% vs. 34%), although this was not statistically significant. HR-HPV was detected in 27% of the nonungual tumours. CONCLUSION: HR-HPV-associated cSCC of the finger appears in younger patients, is smaller and is less infiltrative than non-HR-HPV tumours. The presence of a basaloid morphology and the absence of elastosis and inflammation could be used as markers for HR-HPV detection. The high prevalence of HR-HPV in nonungual cSCC suggests its aetiopathogenic role in these tumours.

Primary Cutaneous Marginal Zone Lymphoproliferative Disorder of Donor Origin after Allogeneic Hematopoietic Stem Cell Transplantation.

ABSTRACT: Primary cutaneous posttransplant lymphoproliferative disorders (PTLDs) after allogeneic hematopoietic stem cell transplant (allo-HSCT) are exceedingly rare, with only 6 published cases, all of them consisting in T-cell neoplasms. In this report, we present for the first time a donor-derived B-cell PTLD consisting in a primary, cutaneous, B-cell, marginal zone, lymphoproliferative disorder (PCMZLPD). The patient, a 37-year-old woman with a history of Hodgkin lymphoma received an allo-HSCT from her healthy, matched, related father, achieving complete host chimerism in the bone marrow and peripheral blood. However, 8 years after the allo-HSCT, she presented asymptomatic skin lesions consisting in oval, well-defined, slightly raised erythematous plaques, located on the arms, trunk, and legs. Skin biopsies of 2 lesions demonstrated a class-switched IgG+, EBV-, PCMZLPD, showing kappa light chain restriction and monoclonal rearrangement of the IgH gene. Microsatellite genotyping and 2-color fluorescence in situ hybridization (X and Y chromosomes) confirmed that the origin of the neoplastic cells was the donor graft. The lesions showed an indolent behavior, good response to topical corticosteroids, and no need for systemic treatment. Our case broadens the spectrum of PTLD, a diverse group of lymphoid and/or plasmacytic proliferations with variable clinical presentations and histopathological features.

Clinical and histopathological evaluation of 50 acantholytic cutaneous squamous cell carcinomas: Analysis outcome in a retrospective case-control study.

BACKGROUND: Acantholytic cutaneous squamous cell carcinomas (aCSCCs) have been classically considered as a high-risk variant of CSCC. However, more recent studies show that aCSCC does not confer more aggressiveness. This study aims to establish whether the prognosis of the aCSCC is worse than that of the non-acantholytic (naCSCC) or not. METHODS: Retrospective case-control study with 50 aCSCCs and 50 naCSCCs. For each aCSCC, an naCSCC with similar high-risk features to the aCSCC but with no acantholysis was selected. Prognosis between both groups was compared. RESULTS: The mean age was 86 years (SD 9.61). Sixty-one patients were men. Thirty-nine CSCCs were located in high-risk head and neck areas. Twenty CSCCs exhibited a poor degree of differentiation, and 36 showed an infiltrative growth pattern. The tumor diameter was 18.71 mm (interquartile range, IQR 35), and the tumor thickness was 6.72 mm (IQR 15.50). Twelve CSCCs exhibited perineural infiltration, and eight CSCCs exhibited invasion beyond the subcutaneous fat. Positive margins after excision of the tumor in 22 aCSCCs vs eight naCSCCs (P < 0.02). Nineteen poor-prognosis events were observed (local recurrence, lymph node metastasis, and death from CSCC). However, no differences were observed between both groups when comparing poor-prognosis events. CONCLUSION: The proportion of unfavorable events is similar in aCSCC and naCSCC. The acantholytic histopathological subtype is not associated with a poorer prognosis than the non-acantholytic CSCC in our cohort.

Value of PD-L1, PD-1, and CTLA-4 Expression in the Clinical Practice as Predictors of Response to Nivolumab and Ipilimumab in Monotherapy in Patients With Advanced Stage Melanoma.

BACKGROUND: The introduction of immune checkpoint inhibitors (ICI) has improved the survival outcomes of patients with advanced melanoma. To date, only a few studies have evaluated the immunohistochemical (IHC) expression of PD-1 and CTLA-4 in tumor-infiltrating lymphocytes (TILs) as predictive markers of response to ICI, most of them in the context of clinical trials. Moreover, the predictive value of PD-L1 in melanoma cells in the response to immunotherapy is unclear. The aim of our study was to assess the IHC expression of PD-L1, PD-1, and CTLA-4 in samples of patients with advanced melanoma and to establish their prognostic value as predictors of ICI response in a university hospital. METHODS: The expression of PD-L1, PD-1, and CTLA-4 was evaluated in pretreatment tumor samples in a series of 35 patients, 21 patients treated with nivolumab and 14 patients with ipilimumab in monotherapy. RESULTS: In the nivolumab group, 4 tumors (19%) were positive for PD-L1 and all of them showed a partial response to the treatment. However, 4 patients whose tumors did not express PD-L1 also responded to nivolumab. PD-1 expression was not associated with better progression-free survival (PFS). In the ipilimumab group, 5 patients (35.7%) showed expression of CTLA-4. Positive cases showed a better PFS; however, one negative case responded to ipilimumab. CONCLUSIONS: Nivolumab produces a better response compared with ipilimumab in patients with melanoma. The IHC expression of PD-L1 and CTLA-4 are associated with a higher response rate to nivolumab and ipilimumab, respectively, and better PFS, but the existence of responder patients with negative expression suggests that they are not adequate biomarkers to select candidate patients for ICI in the clinical practice.

Perineural Invasion as a Clue to Malignant Behavior in a Dermatofibroma.

Dermatofibroma (DF) represents one of the most common mesenchymal proliferations of the skin. Their recurrence rate, even when incompletely excised, is very low, whereas the atypical, aneurysmal, and cellular variants have recurrence rates of up to 20% each. Extraordinary rare malignant lesions with metastases to lymph nodes and/or lung have been described. We report a 64-year-old woman with a long history (years) of a skin lesion on her right arm that became painful during the last months. Histologically, it consisted of a conventional cellular DF in which perineural invasion was present. Subsequently, the lesion showed a clinically aggressive course with recurrences, sarcomatous transformation, and pulmonary metastases. Given that no predictive morphological features have been identified to separate classical benign DF from rare metastasizing forms, perineural invasion in an otherwise conventional DF could be a histopathologic clue for an adverse prognosis and should provoke a closer clinical follow-up.

Pseudolymphomatous Atypical Fibroxanthoma.

Atypical fibroxanthoma is a rare mesenchymal skin tumor of intermediate malignancy that typically occurs on sun-damaged skin of elderly patients. Histologically, it is composed of pleomorphic cells with hyperchromatic nuclei and abundant cytoplasm, commonly arranged in a spindle cell pattern. Different histologic variants have been described during the past years. We present a case of atypical fibroxanthoma containing a dense inflammatory infiltrate, which in conjunction with the existence of immunoblast-like and Reed-Sternberg-like neoplastic cells could be misinterpreted as a lymphoid neoplasm. Immunohistochemical studies revealed strong positivity of tumor cells for CD10 and negativity for cytokeratins, p63, p40, S100, SOX10, ERG, actin, desmin, B and T-cell markers, BCL6, CD15, and CD30. The inflammatory infiltrate contained a mixed reactive T- and B-cell population with negative T-cell receptor and immunoglobulin heavy rearrangements. We discuss the differential diagnosis of this entity in which clinical, immunohistochemical, and molecular features are essential to avoid the diagnosis of a lymphoproliferative disease.

Indeterminate Dendritic Cell Tumor as Cutaneous Involvement of Chronic Myelomonocytic Leukemia Successfully Treated With Phototherapy.

Indeterminate dendritic cell tumor (IDCT) is a rare disease composed of so-called indeterminate cells, a dendritic cell subset displaying histological and some ultrastructural and immunophenotypic features of Langerhans cells, but lacking Birbeck granules. We report a case of cutaneous IDCT occurring in a patient with chronic myelomonocytic leukemia (CMML) successfully treated with UV-A phototherapy. Next-generation sequencing studies of the CMML demonstrated mutations in TET2, ASXL1, and ZRS2 genes, also detected in the IDCT, demonstrating a clonal relationship between both tumors and confirming IDCT as a specific subtype in the spectrum of CMML-related cutaneous lesions.

Cutaneous collagenous vasculopathy: papular form.

Cutaneous collagenous vasculopathy is a rare clinicopathological entity, first described in 2000. Cutaneous collagenous vasculopathy has been considered a form of microangiopathy of superficial dermal vessels and produce lesions that appear as telangiectasia. We present a patient with histopathologic features of cutaneous collagenous vasculopathy and scattered erythematous papules on the trunk with a striking dermatoscopic finding. We propose the term of 'cutaneous papular collagenous vasculopathy' as a new clinical manifestation of this disease.

Xanthomatous Cells in Cutaneous Graft-Versus-Host Disease Biopsies: A Clue for the Diagnosis of Hepatic Graft-Versus-Host Disease.

Graft-versus-host disease (GVHD) is one of the most common and serious complications of hematopoietic stem-cell transplantation that mainly affects the skin, gastrointestinal tract, and liver. Hepatic GVHD is associated with high morbidity and mortality, and its diagnosis can be especially challenging because of nonspecific clinical signs and symptoms. It must be suspected in patients with elevated liver enzymes and cholestasis, especially in those with a history of preceding skin rash and diarrhea. We describe 3 patients with cutaneous and hepatic GVHD that presented with severe hypercholesterolemia and hypertriglyceridemia, and no xanthomatous macular lesions, in which cutaneous biopsies revealed the presence of xanthomatous dermal histiocytes. We propose that the presence of these xanthomatous cells in skin biopsies from patients with cutaneous GVHD could be a dermatopathological clue for the diagnosis of hepatic GVHD.

Familial papular epidermal nevus with "skyline" basal cell layer.

Papular epidermal nevus with "skyline" basal cell layer is a variant of keratinocytic nevus that usually occurs sporadically but may affect different family members. We report on the fourth family with papular epidermal nevus with "skyline" basal cell layer affecting a 3-month-old girl and her father.