Grover disease (GD) is a rather common papular pruritic dermatosis that can be transient, persistent, or asymptomatic. The microscopic diagnosis of clinically suspected lesions can be challenging because GD can adopt different patterns, and involved areas are generally admitted to be mostly focal. The histopathologic hallmark of the disease is acantholysis, frequently combined with dyskeratosis, which confers the lesions an appearance similar to Darier disease, Hailey-Hailey disease, or pemphigus. Eczematous features can be observed as well. In this study of 120 consecutive cases of GD, we have found a sex and age incidence similar to what has been previously described, with no obvious seasonal influence, but careful evaluation of their microscopic features suggests that the histopathological diagnostic criteria of GD should be expanded. Specifically, in addition to the commonly described GD findings, we have detected cases with porokeratosis-like oblique columns of parakeratosis, lesions showing a nevoid or lentiginous silhouette, intraepidermal vesicular lesions, lichenoid changes with basal vacuolization and dyskeratosis, and dysmaturative foci with keratinocyte atypia. Moreover, quite often the dermal infiltrate was composed not only of lymphocytes intermingled with eosinophils, but also of neutrophils. In many cases, the capillary vessels showed hints of vascular damage including endothelial tumefaction due to cytoplasmatic edema and erythrocyte extravasation. Finally, because involved areas were larger than 2 mm in more than 50% of our cases, we should assume that GD lesions are not always as small as commonly claimed. Awareness of the patterns newly described herein may be important to avoid underdiagnosis of GD and may contribute to understand the pathogenesis of this acantholytic disease.

Background Confusion exists regarding interstitial granulomatous dermatitis (IGD) and palisaded neutrophilic and granulomatous dermatitis (PNGD). Objective To determine whether IGD and PNGD are two different entities, or whether they must be considered as two subtypes of the same reactive pattern, and thus whether the unification of the nomenclature is necessary. Methods Observational retrospective multicentre study of patients with IGD and PNGD evaluated between 1999 and 2019 and review of their clinical and histological features. Results We identified 52 patients (38 women and 14 men). Clinical and histological findings of IGD were observed in 88.4% of cases. The most common cutaneous lesions were plaques/macules (IGD) or annular plaques and papules/nodules (PNGD), located mostly on the limbs and trunk. The rope sign was developed in two patients with IGD that associated autoimmune disorders. Similar associated comorbidities (75%) were found in both entities, mainly autoimmune diseases (53.8%). In IGD, the infiltrate was predominantly lympho‐histiocytic. Neutrophilic infiltrates, karyorrhexis and skin lesions with limited clinical course were mainly associated with PNGD biopsies. In biopsies with a limited recurrent course, a predominant lymphocytic inflammatory infiltrate was found. Collagen degeneration was present in 75.9% of cases. The floating sign was observed only in IGD type patients (63%). Overlapping histological findings were found in one fourth of cases, especially between IGD and interstitial granuloma annulare. Interface dermatitis, apparently unrelated to drug intake, was observed in 4 cases of IGD. Conclusion We support the term reactive granulomatous dermatitis to unify both the clinical and histological findings of IGD and PNGD, and the overlapping between IGD and interstitial granuloma annulare. According to this, a spectrum of histological changes will be found depending on the clinical course of the skin lesions.

We report the first case of a grafted-kidney RCC whose recipient's cell origin has been proved by microsatellite analysis. An origin from the recipient's kidney or bone marrow stem cells is proposed as the more plausible hypothesis.

Background: Platinum-based neoadjuvant chemotherapy (NAC) increases the survival of patients with organ-confined urothelial bladder cancer (UBC). In retrospective studies, patients with basal/squamous (BASQ)-like tumors present with more advanced disease and have worse prognosis. Transcriptomics-defined tumor subtypes are associated with response to NAC. Aim: To investigate whether immunohistochemical (IHC) subtyping predicts NAC response. Methods: Patients with muscle-invasive UBC having received platinum-based NAC were identified. Tissue microarrays were used to type tumors for KRT5/6, KRT14, GATA3, and FOXA1. Outcomes: progression-free survival and disease-specific survival; univariable and multivariate Cox regression models were applied. Results: We found a very high concordance between mRNA and protein expression. Using IHC-based hierarchical clustering, we classified 126 tumors in three subgroups: BASQ-like (FOXA1/GATA3 low; KRT5/6/14 high), Luminal-like (FOXA1/GATA3 high; KRT5/6/14 low), and mixed-cluster (FOXA1/GATA3 high; KRT5/6 high; KRT14 low). Applying multivariable analyses, patients with BASQ-like tumors were more likely to achieve a pathological response to NAC (OR 3.96; p = 0.017). The clinical benefit appeared reflected in the lack of significant survival differences between patients with BASQ-like and luminal tumors. Conclusions: Patients with BASQ-like tumors—identified through simple and robust IHC—have a higher likelihood of undergoing a pathological complete response to NAC. Prospective validation is required.