The inverse problem for cardiac arrhythmias.

A cardiac arrhythmia is an abnormality in the rate or rhythm of the heart beat. We study a type of arrhythmia called a premature ventricular complex (PVC), which is typically benign, but in rare cases can lead to more serious arrhythmias or heart failure. There are three known mechanisms for PVCs: reentry, an ectopic focus, and triggered activity. We develop minimal models for each mechanism and attempt the inverse problem of determining which model (and therefore which mechanism) best describes the beat dynamics observed in an ambulatory electrocardiogram. We demonstrate our approach on a patient who exhibits frequent PVCs and find that their PVC dynamics are best described by a model of triggered activity. Better identification of the PVC mechanism from wearable device data could improve risk stratification for the development of more serious arrhythmias.

Increased levels of a pro-inflammatory IgG receptor in the midbrain of people with schizophrenia.

BACKGROUND: There is growing evidence that neuroinflammation may contribute to schizophrenia neuropathology. Elevated pro-inflammatory cytokines are evident in the midbrain from schizophrenia subjects, findings that are driven by a subgroup of patients, characterised as a "high inflammation" biotype. Cytokines trigger the release of antibodies, of which immunoglobulin G (IgG) is the most common. The level and function of IgG is regulated by its transporter (FcGRT) and by pro-inflammatory IgG receptors (including FcGR3A) in balance with the anti-inflammatory IgG receptor FcGR2B. Testing whether abnormalities in IgG activity contribute to the neuroinflammatory abnormalities schizophrenia patients, particularly those with elevated cytokines, may help identify novel treatment targets. METHODS: Post-mortem midbrain tissue from healthy controls and schizophrenia cases (n = 58 total) was used to determine the localisation and abundance of IgG and IgG transporters and receptors in the midbrain of healthy controls and schizophrenia patients. Protein levels of IgG and FcGRT were quantified using western blot, and gene transcript levels of FcGRT, FcGR3A and FcGR2B were assessed using qPCR. The distribution of IgG in the midbrain was assessed using immunohistochemistry and immunofluorescence. Results were compared between diagnostic (schizophrenia vs control) and inflammatory (high vs low inflammation) groups. RESULTS: We found that IgG and FcGRT protein abundance (relative to ß-actin) was unchanged in people with schizophrenia compared with controls irrespective of inflammatory subtype. In contrast, FcGRT and FcGR3A mRNA levels were elevated in the midbrain from "high inflammation" schizophrenia cases (FcGRT; p = 0.02, FcGR3A; p < 0.0001) in comparison to low-inflammation patients and healthy controls, while FcGR2B mRNA levels were unchanged. IgG immunoreactivity was evident in the midbrain, and approximately 24% of all individuals (control subjects and schizophrenia cases) showed diffusion of IgG from blood vessels into the brain. However, the intensity and distribution of IgG was comparable across schizophrenia cases and control subjects. CONCLUSION: These findings suggest that an increase in the pro-inflammatory Fcγ receptor FcGR3A, rather than an overall increase in IgG levels, contribute to midbrain neuroinflammation in schizophrenia patients. However, more precise information about IgG-Fcγ receptor interactions is needed to determine their potential role in schizophrenia neuropathology.

mTOR Inhibitor-Induced Transient Acantholytic Dermatitis.

A 61-year-old Caucasian male with a medical history of metastatic carcinoid presented to dermatology with a new onset severely pruritic “breakouts” on the arms, neck, and chest. Approximately ten years prior, he was diagnosed with a small bowel carcinoid tumor and liver metastases treated with a combination of resection and ablation.

Long ECGs reveal rich and robust dynamical regimes in patients with frequent ectopy.

We have analyzed the electrocardiographic data collected during continuous 7-day ambulatory recordings in patients with frequent premature ventricular complexes (PVCs). We analyze the dependence of the frequency and patterns of PVCs on the heart rate and the time of the day. Patients display rhythms of a complex yet consistent structure. In a given patient, the pattern remains robust over different days and particular repetitive patterns appear at specific heart rates, suggesting the appearance of bifurcations in the dynamics. Over the course of 24 h, we find that in some patients, patterns appear to depend only on the heart rate, whereas in others, both the time of the day and the heart rate play a role in controlling the dynamics. Identifying parameter values at which bifurcations occur facilitates the development of dynamical models for arrhythmia. The use of powerful recording and analysis techniques will enable improved analysis of data and better understanding of mechanisms of arrhythmia in individual patients.

Indeterminate dendritic cell neoplasm of the skin: A 2-case report and review of the literature.

Indeterminate dendritic cell neoplasm (IDCN) is an exceedingly rare and mostly cutaneous histiocytosis, frequently associated with other hematopoietic malignancies. We report 2 cases of multilesional cutaneous IDCN. A 55-year-old male with no associated malignancy and complete response to ultraviolet phototherapy; and a 72-year-old male with chronic myelomonocytic leukemia (CMML). Both cases showed histiocytoid cytology, positivity for CD1a and no expression of langerin or BRAFV600E . With our patients, the literature describes 79 cases of IDCNs, including 65 (82%) with only skin involvement, 7 cases (9%) with involvement of skin and a second site, 5 cases (6%) involving lymph nodes only, 1 splenic lesion and 1 systemic disease. Seventeen cases (22%) were associated with other hematopoietic malignancies, most commonly CMML (6 cases), follicular lymphoma (4 cases) and acute myeloid leukemia (3 cases). All IDCNs associated with myeloid malignancies were limited to the skin, while most cases associated with lymphoma were limited to lymph nodes. Reported responses of cutaneous lesions to ultraviolet phototherapy are encouraging, while systemic chemotherapy is appropriate for clinically aggressive cases and treatment of associated malignancies. Recognition of the clinico-morphologic spectrum of IDCNs should prevent misdiagnoses and prompt investigation of possible associated neoplasms.

Basal Cell Skin Cancer, Version 1.2016, NCCN Clinical Practice Guidelines in Oncology.

Basal cell carcinoma (BCC) of the skin is the most common cancer, with a higher incidence than all other malignancies combined. Although it is rare to metastasize, patients with multiple or frequently recurring BCC can suffer substantial comorbidity and be difficult to manage. Assessment of risk is a key element of management needed to inform treatment selection. The overall management of BCC primarily consists of surgical approaches, with radiation therapy as an alternate or adjuvant option. Many superficial therapies for BCC have been explored and continue to be developed, including topicals, cryosurgery, and photodynamic therapy. Two hedgehog pathway inhibitors were recently approved by the FDA for systemic treatment of advanced and metastatic BCC, and others are in development. The NCCN Guidelines for Basal Cell Skin Cancer, published in full herein, include recommendations for selecting among the various surgical approaches based on patient-, lesion-, and disease-specific factors, as well as guidance on when to use radiation therapy, superficial therapies, and hedgehog pathway inhibitors.

Proliferative activity, chromosomal aberrations, and tumor-specific mutations in the differential diagnosis between blue nevi and melanoma.

Blue nevi are a clinically and pathologically heterogeneous group of benign pigmented dermal melanocytic tumors that may exhibit histologic overlap with malignant melanoma. This study evaluates the role of immunohistochemical and molecular analyses in the classification and differential diagnosis between blue nevi and melanoma. Twenty-three dermal melanocytic tumors, initially diagnosed as benign or ambiguous, were subjected to immunohistochemical staining for phosphohistone H3 and MIB-1 to evaluate mitotic activity, comparative genomic hybridization to detect chromosomal aberrations, and GNAQ, GNA11, BRAF, NRAS, and KRAS sequencing. Of 19 patients with follow-up information (median, 1.6 years), 3 developed recurrent or metastatic disease. Nevertheless, 11 of the 19 patients with follow-up had <2 years of follow-up. Nine of 23 patients showed chromosomal aberrations, including all 3 patients with tumor recurrence or progression. There was no significant correlation between mutation status (P = 0.6) or mitotic rate (P = 0.3) and outcome. In conclusion, three of nine patients with chromosomal aberrations developed tumor recurrence or progression. Patients with histologically ambiguous dermal melanocytic proliferations that exhibit copy number aberrations should undergo careful clinical follow-up.

Unanswered questions in the management of stage I-III Merkel cell carcinoma.

Many unanswered questions remain about what constitutes appropriate guidelines for treatment of Merkel cell carcinoma (MCC). In this review, we address current uncertainty surrounding optimal management of MCC. These areas of uncertainty include early recognition features; clinical and histopathologic prognostic factors; optimum margins of excision of the primary tumor; indications for and value of surgical staging of the clinically negative regional nodes; optimum management of the patient with pathologically positive regional nodes; and indications for and value of radiation to the primary and regional nodes. Through identifying and elaborating on these areas of uncertainty, the authors hope to foster additional research and ultimately improve the evidence base for future iterations of the NCCN Clinical Practice Guidelines in Oncology in this rare but increasingly encountered cutaneous malignancy. The intent, however, is not to exhaustively identify all areas of controversy, but rather to highlight clinically relevant questions that further studies could address to improve the standard of care for MCC.

Merkel cell carcinoma, version 1.2014.

Merkel cell carcinoma is a rare, aggressive cutaneous tumor that combines the local recurrence rates of infiltrative nonmelanoma skin cancer with the regional and distant metastatic rates of thick melanoma. The NCCN Guidelines for Merkel Cell Carcinoma provide recommendations on the diagnosis and management of this aggressive disease based on clinical evidence and expert consensus. This version includes revisions regarding the use of PET/CT imaging and the addition of a new section on the principles of pathology to provide guidance on the analysis, interpretation, and reporting of pathology results.

Dermatofibrosarcoma protuberans, version 1.2014.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue tumor characterized by a relatively high risk of local recurrence and low risk of metastasis. The NCCN Guidelines for DFSP provide multidisciplinary recommendations on the management of patients with this rare disease. These NCCN Guidelines Insights highlight the addition of the Principles of Pathology section, which provides recommendations on the pathologic assessment of DFSP. Because DFSP can mimic other lesions, immunohistochemical studies are often required to establish diagnosis. Cytogenetic testing for the characteristic translocation t(17;22)(q22;q13) can also be valuable in the differential diagnosis of DFSP with other histologically similar tumors.

Composite hemangioendothelioma and its classification as a low-grade malignancy.

Hemangioendotheliomas are vascular neoplasms occupying a spectrum of biological potential ranging from benign to low-grade malignancy. Composite hemangioendothelioma (CH) is one of the less commonly encountered variants exhibiting a mixture of elements of other hemangioendothelioma subtypes, such as epithelioid, retiform, and spindle cell. Some authors have identified areas histopathologically equivalent to angiosarcoma within CH, raising the question of the true nature of this neoplasm. Although CH recurs locally, there are only 3 reported cases which metastasized. To date, 26 cases (including the present case) have been described in the literature. Herein, we describe a unique case of CH arising in the background of previous radiation therapy and long-standing lymphedema (classically associated with the development of angiosarcoma-Stewart-Treves syndrome) that harbored higher grade areas but behaved as a low-grade malignant neoplasm. This, in conjunction with the many reported cases of CH-harboring angiosarcoma-like areas, and the occasional association with a history of lymphedema, raises the question of whether this variant of hemangioendothelioma may actually be an angiosarcoma that behaves prognostically better than the conventional type. After careful study of the natural disease progression of the current case and review of the literature, we discuss justification for the continued classification of CH as a low-grade malignancy.

Case-control study of smoking and non-melanoma skin cancer.

OBJECTIVE: To investigate the association between cigarette smoking and basal and squamous cell carcinomas (BCC and SCC) of the skin, a clinic-based case-control study was conducted in Tampa, FL. METHODS: Patients with histologically confirmed BCC/SCC were recruited from a university dermatology clinic (n = 215 BCC, 165 SCC). Controls were comprised of individuals with no history of skin cancer who screened negative for skin cancer upon physical examination at the affiliated cancer screening or primary care clinics (n = 315). Information on smoking and other risk factors was obtained from self-administered questionnaires. RESULTS: After adjustment for age, sex, and other skin cancer-risk factors, ever smoking was not associated with BCC (odds ratio (OR) = 1.26, 95% confidence interval (CI) = 0.83-1.92), but was statistically significantly associated with SCC (OR = 1.97, 95% CI = 1.19-3.26), with significant trends observed for SCC associated with increasing cigarettes per day (p = 0.01) and pack-years smoked (p = 0.01). Among men, smoking ≥20 pack-years was associated with non-significant increased risks of BCC (OR = 1.90, 95% CI = 0.88-4.12) and SCC (OR = 1.97, 95% CI = 0.84-4.66), whereas among women, no association was observed with BCC (OR = 0.98, 95% CI = 0.39-2.46) while a statistically significant three-fold risk was observed with SCC (OR = 3.00, 95% CI = 1.02-8.80). CONCLUSION: Cigarette smoking is more strongly associated with SCC than BCC, particularly among women.

Primary cutaneous B-cell lymphomas: recent advances in diagnosis and management.

BACKGROUND: Primary cutaneous B-cell lymphoma (PCBCL) is a heterogeneous group of rare clonal B-cell lymphoproliferative disorders with distinct clinicopathologic features from more common nodal B-cell lymphomas. METHODS: We performed a systematic review of the relevant literature in the MEDLINE database and analyzed laboratory and clinical data. This review discusses the three most common types of PCBCL: primary cutaneous marginal zone lymphoma (PCMZL), primary cutaneous follicle-center lymphoma (PCFCL), and primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL, LT). RESULTS: Skin biopsies with histology, immunohistochemistry, and molecular clonality studies are essential for a correct diagnosis of cutaneous B-cell lymphoma. Comprehensive lymphoma staging with laboratory and imaging studies and bone marrow aspiration and biopsy are important for determining the prognosis and differentiation of PCBCL from secondary skin involvement with systemic B-cell lymphomas. PCMZL and PCFCL are low-grade PCBCLs, with an estimated 5-year disease-specific survival rate of greater than 95%. Surgical excision or focal radiation therapy is sufficient to control stages T1 and T2 disease. Rituximab monotherapy is frequently used for patients with stage T3 disease. PCDLBCL, LT is an intermediate-grade B-cell lymphoma, with a 5-year disease-specific survival rate of approximately 50%. An anthracycline-based chemotherapy regimen with rituximab is usually required as initial therapy to improve outcomes. CONCLUSIONS: In less than a decade, significant progress has been made in our understanding of PCBCL. Novel classification, staging, and prognostic systems have resulted in more accurate diagnosis and prognosis. Although no randomized prospective studies have been conducted in PCBCL, therapies derived from systemic B-cell lymphomas have shown promising results.

The impact of the World Trade Center attack on FDNY firefighter retirement, disabilities, and pension benefits.

BACKGROUND: Our goal was to examine the effect of the World Trade Center (WTC) attack and subsequent New York City Fire Department (FDNY) rescue/recovery activities on firefighter retirements. We also analyzed the financial impact associated with the increased number and proportion of service-connected "accidental" disability retirements on the FDNY pension system. METHODS: A total of 7,763 firefighters retired between 9/11/1994 and 9/10/2008. We compared the total number of retirements and the number and proportion of accidental disability retirements 7 years before and 7 years after the WTC attack. We categorized WTC-related accidental disability retirements by medical cause and worked with the New York City Office of the Actuary to approximate the financial impact by cause. RESULTS: In the 7 years before 9/11 there were 3,261 retirements, 48% (1,571) of which were accidental disability retirements. In the 7 years after 9/11, there were 4,502 retirements, 66% (2,970) were accidental disability retirements, of which 47% (1,402) were associated with WTC-related injuries or illnesses. After 9/11, the increase in accidental disability retirements was, for the most part, due to respiratory-related illnesses. Additional increases were attributed to psychological-related illnesses and musculoskeletal injuries incurred at the WTC site. Pension benefits associated with WTC-related accidental disability retirements have produced an increased financial burden of over $826 million on the FDNY pension system. CONCLUSIONS: The WTC attacks affected the health of the FDNY workforce resulting in more post-9/11 retirements than expected, and a larger proportion of these retirees with accidental disability pensions.

An unusually large eccrine poroma: a case report and review of the literature.

The eccrine poroma is an uncommon benign neoplasm previously thought to originate solely from the eccrine sweat gland. Initially believed to present on hairless acral surfaces, a more extensive distribution has been described. We report a case of a 55-year-old man with a slowly growing, 6-cm eccrine poroma on the medial aspect of his right foot of 40 years' duration. Clinicians should be aware that poromas can be of either eccrine or apocrine origin and can occur in areas other than acral skin. They also should understand the subclassification of the poroma family of neoplasms.

Useof anti-phosphohistone H3 immunohistochemistry to determine mitotic rate in thin melanoma.

The seventh edition of the American Joint Committee on Cancer (AJCC) melanoma staging system, slated for release in 2010, will introduce mitotic rate (MR) as one of the primary criteria for staging thin melanoma (< or = 1.0 mm). Accurate counts are essential because the finding of a single mitotic figure (MF) will alter the staging and management of these patients. The traditional manner of counting of mitotic figures (MFs) using a X40 objective is time consuming and prone to inter- and intraobserver variability. We employed an antibody to phosphohistone H3 (pHH3, ser10) that labels MFs in all stages of mitosis, to evaluate mitotic counts at X20 in tissue sections from 30 melanoma patients with thin lesions 0.45 to 1.2 mm in depth, and compared results with routine hematoxylin and eosin (H&E) in a double-blind fashion. The mean MR was 1.63 by antipHH3, and 0.67 for H&E, representing a mean increase of 243%. The Spearman correlation coefficient for MR in H&E and anti-pHH3 sections was 0.88 (P < 0.0001). When melanomas were designated as "mitotically active," if the MR by anti-pHH3 was > or = 2 and > or = 1 by H&E, the correlation coefficient increased to 1.0. No thin melanomas were mitotically inactive on anti-pHH3 but active on H&E. Results indicate that anti-pHH3 is a useful immunostain for labeling melanocytes in mitosis. Subsequent studies will be needed confirm the accuracy of this staining technique, which has the potential to be used as a screening method for counting MFs before conventional H&E methodology in the microstaging of thin melanoma.

Rapid frozen section immunostaining of melanocytes by microphthalmia-associated transcription factor.

Mohs micrographic surgery (MMS) has increasingly become an accepted therapy for melanoma in situ on chronically sun damaged skin (CSDS). However, melanocytes are difficult to locate in frozen material on hematoxylin and eosin. In addition, determining the cut-off between the melanoma and the "atypical melanocytic hyperplasia" in CSDS can be challenging in frozen or formalin-fixed paraffin-embedded sections, with or without immunohistochemistry (IHC). In this article, we report the use of a rapid, 35-minute protocol using microphthalmia-associated transcription factor (MITF) IHC for identifying melanocytes in frozen tissue for its potential use in MMS. In contrast to melanoma antigen recognized by T cells (MART-1), MITF is a nuclear stain, which simplifies identification of melanocytes and quantification of melanocytic parameters. In this study, MITF IHC in frozen sections yielded equivalent melanocyte nuclear diameter and density measurements compared with formalin-fixed paraffin-embedded sections. Nuclear diameter measurements obtained with MITF were similar to that previously reported with MART-1, but the melanocyte density figures were lower. Reliable labeling of melanocytes in frozen sections required the use of diaminobenzidine (DAB) chromogen with Giemsa counterstaining and a buffer devoid of surfactant. Our experience with MITF IHC indicates that it is a dependable immunostain in frozen sections, and may prove to be useful in MMS as an adjunct to hematoxylin and eosin and MART-1 IHC for interpretation of margins for melanoma in situ on CSDS.

Systemic retinoids for chemoprevention of non-melanoma skin cancer in high-risk patients.

Patients at high risk for the development of multiple non-melanoma skin cancers, especially those receiving immunosuppressive medications following solid organ transplantation, are candidates for chemoprophylaxis. In patients where photo-protection and topical medications are insufficient to prevent the growth of new cancers, there is considerable evidence that oral retinoids, including vitamin A, and synthetics such as isotretinoin, etretinate and acitretin are efficacious in this regard. This manuscript is a review of the literature regarding the use of these agents for chemoprophylaxis of non-melanoma skin cancer. Also included is anecdotal evidence that bexarotene, a rexinoid, may be as effective as acitretin in terms of chemoprevention, with a comparable side effects at doses recommended for chemoprophylaxis.

Advances in immunostains used in Mohs surgery.

In recent years, Mohs micrographic surgery (MMS) has become a widely utilized method of removal for a variety of cutaneous neoplasms. Certain clinical scenarios, however, make it difficult to visualize residual tumor cells, potentially decreasing the efficacy of the Mohs procedure. Immunohistochemical (IHC) stains are now available and are being utilized to delineate cells of interest intraoperatively when routinely stained slides are equivocal. While useful, IHC stains have not gained wide acceptance as an adjunct to MMS, particularly due to increased processing time, cost and workload required. There have been multiple recent advances, however, in the utilization of IHC stains in MMS. In this article, the authors discuss recent advances in IHC stains used in MMS for the treatment of melanoma as well as nonmelanoma skin cancers, potentially making their routine use in select cases more feasible.

Mohs surgery for melanoma in situ: how we do it.

The advent of rapid immunostains has made the use of Mohs surgery to treat melanoma more practical. Mohs surgery is especially useful in the management of lentigo maligna, which often has indistinct clinical margins. The authors describe their technique for treating melanoma in situ with Mohs surgery.