Many cases of superinfected hidradenitis suppurativa (HS) involve multiple species of bacteria, but gas-producing infections are rare and can complicate the clinical picture. Additionally, recognizing squamous cell carcinoma (SCC) as a complication of longstanding HS is imperative. Herein, we present a unique case of a severe emphysematous HS that was initially mistaken for Fournier gangrene and eventually diagnosed as superinfected SCC.

Background: Quality of life (QOL) in hidradenitis suppurativa (HS) patients is negatively impacted by physical and psychosocial problems. The aim of this study was to investigate the frequency and severity of HS-specific symptoms and to correlate these with disease severity. Methods We analyzed medical record data from 145 patients seen in an academic HS specialty clinic between August 2009 to March 2018. Results Hurley stage III patients had significantly higher mean Dermatology Life Quality Index (DLQI) scores (20.2) compared to patients with Hurley stage I (11.3) and II (13.9), (P<0.001 and P=0.001, respectively). More than 75% of patients reported physical symptoms of drainage, irritation, pain, itching, bleeding, and odor. There were associated psychosocial problems of embarrassment and self-consciousness. Symptom severity was most strongly correlated with disease severity for odor (correlation coefficient 0.4, P<0.001), difficulty moving arms (0.323, P<0.001), negative impact on job/school (0.303, P<0.001), and negative impact on relationships (0.298, P<0.001). Conclusion Our results highlight the significant burden of HS and the need for a more comprehensive, HS-specific evaluation tool to better assess the QOL of this patient population. Limitations A small cohort in a single academic center.

Therapies that target the programmed death-1 (PD-1) receptor have shown unprecedented rates of durable clinical responses in patients with various cancer types. One mechanism by which cancer tissues limit the host immune response is via upregulation of PD-1 ligand (PD-L1) and its ligation to PD-1 on antigen-specific CD8(+) T cells (termed adaptive immune resistance). Here we show that pre-existing CD8(+) T cells distinctly located at the invasive tumour margin are associated with expression of the PD-1/PD-L1 immune inhibitory axis and may predict response to therapy. We analysed samples from 46 patients with metastatic melanoma obtained before and during anti-PD-1 therapy (pembrolizumab) using quantitative immunohistochemistry, quantitative multiplex immunofluorescence, and next-generation sequencing for T-cell antigen receptors (TCRs). In serially sampled tumours, patients responding to treatment showed proliferation of intratumoral CD8(+) T cells that directly correlated with radiographic reduction in tumour size. Pre-treatment samples obtained from responding patients showed higher numbers of CD8-, PD-1- and PD-L1-expressing cells at the invasive tumour margin and inside tumours, with close proximity between PD-1 and PD-L1, and a more clonal TCR repertoire. Using multivariate analysis, we established a predictive model based on CD8 expression at the invasive margin and validated the model in an independent cohort of 15 patients. Our findings indicate that tumour regression after therapeutic PD-1 blockade requires pre-existing CD8(+) T cells that are negatively regulated by PD-1/PD-L1-mediated adaptive immune resistance.

We explored the association between liver metastases, tumor CD8⁺ T-cell count, and response in patients with melanoma or lung cancer treated with the anti-PD-1 antibody, pembrolizumab. The melanoma discovery cohort was drawn from the phase I Keynote 001 trial, whereas the melanoma validation cohort was drawn from Keynote 002, 006, and EAP trials and the non-small cell lung cancer (NSCLC) cohort from Keynote 001. Liver metastasis was associated with reduced response and shortened progression-free survival [PFS; objective response rate (ORR), 30.6%; median PFS, 5.1 months] compared with patients without liver metastasis (ORR, 56.3%; median PFS, 20.1 months) P ≤ 0.0001, and confirmed in the validation cohort (P = 0.0006). The presence of liver metastasis significantly increased the likelihood of progression (OR, 1.852; P < 0.0001). In a subset of biopsied patients (n = 62), liver metastasis was associated with reduced CD8⁺ T-cell density at the invasive tumor margin (liver metastasis⁺ group, n = 547 ± 164.8; liver metastasis^- group, n = 1,441 ± 250.7; P < 0.016). A reduced response rate and shortened PFS was also observed in NSCLC patients with liver metastasis [median PFS, 1.8 months; 95% confidence interval (CI), 1.4-2.0], compared with those without liver metastasis (n = 119, median PFS, 4.0 months; 95% CI, 2.1-5.1), P = 0.0094. Thus, liver metastatic patients with melanoma or NSCLC that had been treated with pembrolizumab were associated with reduced responses and PFS, and liver metastases were associated with reduced marginal CD8⁺ T-cell infiltration, providing a potential mechanism for this outcome. Cancer Immunol Res; 5(5); 417-24. ©2017 AACR.