Extensive Perineural Invasion vs Nerve Caliber to Assess Cutaneous Squamous Cell Carcinoma Prognosis.

Importance: Perineural invasion (PNI) is an adverse risk feature in cutaneous squamous cell carcinoma (CSCC) that affects patient prognosis and disease management. However, research comparing different PNI patterns on patient outcomes is limited. Objective: To compare 4 assessments of PNI in CSCC, their associations with poor outcomes, and implications for their inclusion in the Brigham and Women's Hospital (BWH) staging system. Design, Setting, and Participants: This retrospective cohort study was performed at a single tertiary care institution and compared 4 PNI assessments: nerve caliber, number of involved nerves per section, PNI maximal depth, and PNI location with respect to tumor. Patients with primary, localized, invasive CSCC with PNI diagnosed between January 1, 2000, and December 31, 2017, were identified via an electronic in-house database. Available pathology slides were secondarily reviewed by study authors. Relevant patient and tumor characteristics and outcomes were abstracted from the medical record. Data analysis was performed between September 6 and October 20, 2022. Main Outcomes and Measures: Risks of recurrence, disease-specific death, and a composite end point (any poor outcome) were calculated via multivariable stepwise Fine and Gray competing-risks regression. Considered revisions to the BWH staging system were assessed via receiver operating characteristic curves and test characteristics. Results: This study included 140 patients with CSCC, with a mean (SD) age of 75.1 (11.2) years. More than half of the patients were men (93 [66.4%]), and most identified as White (132 [94.3%]). Of the 4 PNI assessments studied, only involvement of multiple nerves was associated with poor outcomes. Perineural invasion of 5 or more distinct nerves (extensive PNI [ePNI]) was independently associated with local recurrence (subhazard ratio [SHR], 13.83 [95% CI, 3.50-54.62]; P < .001), disease-specific death (SHR, 6.20 [95% CI, 1.59-24.21]; P = .009), and any poor outcome (SHR, 10.21 [95% CI, 2.88-36.15]; P < .001). A revised BWH staging system with substitution of ePNI for large-caliber PNI resulted in improved area under the curve and test characteristics compared with current BWH staging criteria that use nerve caliber as the measure of PNI. Conclusions and Relevance: The findings of this cohort study suggest that ePNI is the best prognostic measure of PNI. Because ePNI obviated the need for a micrometer and had superior prognostic capacity to nerve caliber in this cohort, ePNI should be considered for inclusion in CSCC tumor staging. Inclusion of ePNI as a high-risk factor in CSCC staging systems may optimize patient selection for primary treatment and adjuvant interventions.

RNA is required for the integrity of multiple nuclear and cytoplasmic membrane-less RNP granules.

Numerous membrane-less organelles, composed of a combination of RNA and proteins, are observed in the nucleus and cytoplasm of eukaryotic cells. These RNP granules include stress granules (SGs), processing bodies (PBs), Cajal bodies, and nuclear speckles. An unresolved question is how frequently RNA molecules are required for the integrity of RNP granules in either the nucleus or cytosol. To address this issue, we degraded intracellular RNA in either the cytosol or the nucleus by the activation of RNase L and examined the impact of RNA loss on several RNP granules. We find the majority of RNP granules, including SGs, Cajal bodies, nuclear speckles, and the nucleolus, are altered by the degradation of their RNA components. In contrast, PBs and super-enhancer complexes were largely not affected by RNA degradation in their respective compartments. RNA degradation overall led to the apparent dissolution of some membrane-less organelles, whereas others reorganized into structures with altered morphology. These findings highlight a critical and widespread role of RNA in the organization of several RNP granules.

Differential Molecular Expression Patterns Associated with Metastasis in Cutaneous Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis.

The majority of cutaneous squamous cell carcinomas are treated by surgical removal; however, approximately 4% of tumors will metastasize. Molecular expression testing may improve accuracy in estimating the prognosis and defining the mechanisms important in the disease progression, which may impact response to therapy. Using PubMed (MEDLINE) and EMBASE, a systematic review was performed to evaluate studies published from January 2005 to August 2019 reporting tumor protein or RNA expression along with either outcomes (metastasis or death) or a comparison of primary with metastatic tumor samples. Inclusion criteria were met by 45 studies containing 81 comparisons of 44 distinct proteins and 25 microRNAs. On meta-analysis of studies analyzing primary tumor samples in terms of later outcomes, high primary tumor expression of PD-L1 (OR = 2.34, 95% confidence interval = 1.09-5.02, P = 0.030), EGFR (OR = 2.57, 95% confidence interval = 1.24-5.33, P = 0.011), and podoplanin (OR = 2.33, 95% confidence interval = 1.00-5.41, P = 0.049) conferred increased odds for metastasis. In comparison, metastatic tissue was more likely to have a high expression of PD-L1 than primary tissue (OR = 3.13, 95% confidence interval = 1.00-9.75, P = 0.049). Further studies are needed to confirm whether testing for PD-L1, EGFR, and podoplanin expression aids in cutaneous squamous cell carcinomas prognostic estimation of metastasis or death or predicts response to therapy.

Diagnostic Biopsy via In-Office Frozen Sections for Clinical Nonmelanoma Skin Cancer.

BACKGROUND: Treatment of nonmelanoma skin cancer (NMSC) by Mohs surgery has traditionally relied on previous pathologic evaluation of paraffin-embedded tissue. Tissue processing by frozen sections allows for expedited diagnosis and treatment; however, data on its accuracy are limited. OBJECTIVE: To measure the accuracy and outcomes of biopsy via frozen sections for clinical NMSC. METHODS: Biopsies of clinical NMSCs processed via frozen sections with in-office diagnosis rendered by one Mohs surgeon were retrospectively reviewed by one board-certified dermatopathologist. Discordant diagnoses were re-read in blinded fashion by both physicians. If still discordant, final diagnosis was determined by consensus discussion. Inter-rater reliability was calculated using Cohen's kappa statistic. RESULTS: Two hundred ninety-seven lesions from 208 patients were included. Correlation between in-office and final diagnosis was 0.876 indicating "almost perfect" concordance. Sensitivity and specificity of in-office diagnosis for detecting malignancy were 98.1% and 94.4%. Seven cases (2.0%) had a clinically relevant change in final diagnosis, but appropriate treatment had been rendered. Two benign lesions (0.7%) initially diagnosed as malignant underwent excision. CONCLUSION: In-office biopsy via frozen sections is highly accurate in confirming NMSC. This practice may speed diagnosis and treatment thus improving outcomes and patient satisfaction.

A multi-center study on safety and efficacy of immune checkpoint inhibitors in cancer patients with kidney transplant.

Immune checkpoint inhibitors (ICIs) are widely used for various malignancies. However, their safety and efficacy in patients with a kidney transplant have not been defined. To delineate this, we conducted a multicenter retrospective study of 69 patients with a kidney transplant receiving ICIs between January 2010 and May 2020. For safety, we assessed the incidence, timing, and risk factors of acute graft rejection. For efficacy, objective response rate and overall survival were assessed in cutaneous squamous cell carcinoma and melanoma, the most common cancers in our cohort, and compared with stage-matched 23 patients with squamous cell carcinoma and 14 with melanoma with a kidney transplant not receiving ICIs. Following ICI treatment, 29 out of 69 (42%) patients developed acute rejection, 19 of whom lost their allograft, compared with an acute rejection rate of 5.4% in the non-ICI cohort. Median time from ICI initiation to rejection was 24 days. Factors associated with a lower risk of rejection were mTOR inhibitor use (odds ratio 0.26; 95% confidence interval, 0.09-0.72) and triple-agent immunosuppression (0.67, 0.48-0.92). The objective response ratio was 36.4% and 40% in the squamous cell carcinoma and melanoma subgroups, respectively. In the squamous cell carcinoma subgroup, overall survival was significantly longer in patients treated with ICIs (median overall survival 19.8 months vs. 10.6 months), whereas in the melanoma subgroup, overall survival did not differ between groups. Thus, ICIs were associated with a high risk of rejection in patients with kidney transplants but may lead to improved cancer outcomes. Prospective studies are needed to determine optimal immunosuppression strategies to improve patient outcomes.

Molecular prediction of metastasis in cutaneous squamous cell carcinoma.

PURPOSE OF REVIEW: Cutaneous squamous cell carcinoma (cSCC) is a highly prevalent malignancy frequently occurring on body surfaces chronically exposed to ultraviolet radiation. While a large majority of tumors remain localized to the skin and immediate subcutaneous tissue and are cured with surgical excision, a small subset of patients with cSCC will develop metastatic disease. Risk stratification for cSCC is performed using clinical staging systems, but given a high mutational burden and advances in targeted and immunotherapy, there is growing interest in molecular predictors of high-risk disease. RECENT FINDINGS: Recent literature on the risk for metastasis in cSCC includes notable findings in genes involved in cell-cycle regulation, tumor suppression, tissue invasion and microenvironment, interactions with the host-immune system, and epigenetic regulation. SUMMARY: cSCC is a highly mutated tumor with complex carcinogenesis. Regulators of tumor growth and local invasion are numerous and increasingly well-understood but drivers of metastasis are less established. Areas of importance include central system regulators (NOTCH, miRNAs), proteins involved in tissue invasion (podoplanin, E-cadherin), and targets of existing and emerging therapeutics (PD-1, epidermal growth factor receptor). Given the complexity of cSCC carcinogenesis, the use of machine learning algorithms and computational genomics may provide ultimate insight and prospective studies are needed to verify clinical relevance.

A 63-Year-Old Male with AIDS and Diffuse Violaceous Plaques.

Hyperkeratotic Kaposi's sarcoma (KS) is a rare clinicopathologic variant of AIDS-related KS that typically presents with chronic lymphedema and diffuse hyperkeratotic plaques of the lower extremities. Histopathologically, this variant is defined by epidermal hyperplasia, thickened lymphatic walls, and increased numbers of dermal fibroblasts and vascular spaces. Herein, we report the case of a 63-year-old HIV-positive male who presented with this rare hyperkeratotic variant of AIDS-related KS.

Genomic Analysis of the DNA Replication Timing Program during Mitotic S Phase in Maize (Zea mays) Root Tips.

All plants and animals must replicate their DNA, using a regulated process to ensure that their genomes are completely and accurately replicated. DNA replication timing programs have been extensively studied in yeast and animal systems, but much less is known about the replication programs of plants. We report a novel adaptation of the "Repli-seq" assay for use in intact root tips of maize (Zea mays) that includes several different cell lineages and present whole-genome replication timing profiles from cells in early, mid, and late S phase of the mitotic cell cycle. Maize root tips have a complex replication timing program, including regions of distinct early, mid, and late S replication that each constitute between 20 and 24% of the genome, as well as other loci corresponding to ∼32% of the genome that exhibit replication activity in two different time windows. Analyses of genomic, transcriptional, and chromatin features of the euchromatic portion of the maize genome provide evidence for a gradient of early replicating, open chromatin that transitions gradually to less open and less transcriptionally active chromatin replicating in mid S phase. Our genomic level analysis also demonstrated that the centromere core replicates in mid S, before heavily compacted classical heterochromatin, including pericentromeres and knobs, which replicate during late S phase.

A 71-Year-Old Female with Myocardial Infarction and Long-Standing Ulcers on the Thigh.

Calciphylaxis is most commonly encountered in patients with end-stage renal disease; however, it is increasingly observed in nonuremic patients as well. It is important to consider and diagnose nonuremic calciphylaxis early, as prompt treatment and mitigation of associated risk factors is essential to improve long-term outcomes for these patients. Here, we present the case of a 71-year-old woman with atrial fibrillation on warfarin, but without renal disease, who presented with two long-standing ulcers on her thigh and was diagnosed with the aid of biopsy with calciphylaxis. We review the existing literature on the subject and offer this case as a representative report of a clinicopathologic correlation for this disorder.

A flow cytometric method for estimating S-phase duration in plants.

The duration of the DNA synthesis stage (S phase) of the cell cycle is fundamental in our understanding of cell cycle kinetics, cell proliferation, and DNA replication timing programs. Most S-phase duration estimates that exist for plants are based on indirect measurements. We present a method for directly estimating S-phase duration by pulse-labeling root tips or actively dividing suspension cells with the halogenated thymidine analog 5-ethynl-2'-deoxyuridine (EdU) and analyzing the time course of replication with bivariate flow cytometry. The transition between G1 and G2 DNA contents can be followed by measuring the mean DNA content of EdU-labeled S-phase nuclei as a function of time after the labeling pulse. We applied this technique to intact root tips of maize (Zea mays L.), rice (Oryza sativa L.), barley (Hordeum vulgare L.), and wheat (Triticum aestivum L.), and to actively dividing cell cultures of Arabidopsis (Arabidopsis thaliana (L.) Heynh.) and rice. Estimates of S-phase duration in root tips were remarkably consistent, varying only by ~3-fold, although the genome sizes of the species analyzed varied >40-fold.

Single-Cell Squamous Carcinoma: An Underreported High-Risk Variant.

BACKGROUND: There is increasing interest in establishing diagnostic and treatment guidelines for high-risk squamous cell carcinoma (SCC). Single-cell SCC has been recognized as a high-risk subtype but continues to be a less commonly reported and more poorly understood variant. OBJECTIVE: To present the current literature on single-cell SCC. MATERIALS AND METHODS: A review of the literature on single-cell squamous cell carcinoma. RESULTS: There are fewer than 100 cases of single-cell SCC in the literature. The reporting studies demonstrate an increase in the risk of metastasis compared with non-single-cell tumors. Confounding variables reported include other coexisting high-risk features: diameter >2 cm, depth >6 mm, and difficulty detecting single tumor cells. It is therefore unclear whether single-cell SCC is an independent risk factor for recurrence and regional spread. Studies have described use of immunostaining as a means to improve tumor detection. CONCLUSION: Single-cell SCC continues to be an underreported SCC variant. Given its apparent aggressive behavior, more studies are warranted to better understand its tumor biology and behavior and to improve patient outcomes. Based on our present knowledge, complete tumor excision with or without the aid of immunostaining and use of multidisciplinary care are recommended.

Trichophytum rubrum endonyx onychomycosis resistant to standard oral and topical therapies.

We present a 45 year-old man with an eight-year history of discoloration of the nail plate on his left hallux. He had been treated with two courses of oral terbinafine and topical 8% ciclopirox for presumed onychomycosis. On exam, his left great toenail contained a wide yellow-white longitudinal band involving a majority of the nail plate. No subungual debris, hyperkeratosis, or paronychial inflammation was present in the affected nail. Histopathology of the nail plate revealed numerous fungal elements arranged transversely and longitudinally, solely within the keratin layers of the nail plate; these were highlighted with periodic acid-Schiff (PAS) stain confirming endonyx onychomycosis. Cultures grew Trichophyton rubrum. All types of onychomycosis under the new classification system proposed by Hay et al. have now been associated with T. rubrum. Endonyx related to T. rubrum may be a particularly difficult infection to treat with oral or topical agents owing to the absence of robust local immune response and limited drug penetration to the interior nail plate. Physicians should be aware that this type of infection may require treatment with dual-agent therapy or alternative modalities including chemical or surgical plate avulsion or photodynamic therapy.

Basal cell carcinomas of the ear are more aggressive than on other head and neck locations.

BACKGROUND: On pathology review, basal cell carcinomas (BCCs) on the ear more commonly present as aggressive subtypes. It is unclear if this histologic observation translates into more clinically aggressive tumors. OBJECTIVE: We sought to determine the clinical aggressiveness of ear BCCs compared with BCCs elsewhere on the head and neck. METHODS: We conducted a retrospective chart review of all BCCs treated at an academic center from 2005 through 2012. Subjects were divided into ear and non-ear groups. Subtypes classified as "aggressive" included morpheaform, infiltrative, micronodular, adenoid, metatypical, and mixed histology. RESULTS: Of the 7732 head and neck BCCs, 758 (9.8%) were on the ear. Ear BCCs presented as larger lesions (1.28 vs 0.98 cm(2)), required more Mohs layers (16.5% vs 10.7%), and produced a larger final defect (4.29 vs 3.49 cm(2)) than non-ear lesions. When comparing only aggressive subtypes, ear BCCs also presented as larger lesions (1.42 vs 1.23 cm(2)), more frequently required 3 or more layers for clearance (22.3% vs 14.2%), and produced a larger final defect (4.92 vs 4.21 cm(2)) than non-ear lesions. LIMITATIONS: Limitations include single-center design and lack of long-term follow-up. CONCLUSION: Ear BCCs appear to exhibit greater subclinical extension compared with non-ear head and neck BCCs. Therefore, the ear should be considered a high-risk location for BCCs.

A mentorship-based preclinical elective increases exposure, confidence, and interest in surgery.

BACKGROUND: The predicted shortage of surgeons is of growing concern with declining medical student interest in surgical careers. We hypothesized that earlier exposure to operative experiences and the establishment of resident mentors through a preclinical elective would enhance student confidence and interest in surgery. METHODS: We developed a preclinical elective in surgery, which served as an organized curriculum for junior medical students to experience surgery through a paired resident-mentorship model. We assessed student exposure and confidence with clinical activities before and after the elective (N = 24, 100% response rate). We compared these students with a cohort of peers not enrolled in the elective (N = 147, 67% response rate). RESULTS: We found significantly improved confidence (2.8 vs 4.4) and clinical exposure (2.4 vs 4.3) before versus after the elective, with precourse scores equal to matched peers. CONCLUSIONS: This elective incorporates elements that have been shown to positively influence student decision making in surgical career choice. The mentorship model promotes residents as educators, whereas the elective provides a means for early identification of students interested in surgery.