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Cosmetic and laser procedures are increasingly popular among patients and are skills in which dermatologists are regarded as well trained. Most dermatology residents intend to incorporate cosmetic procedures into their practice and prefer to learn such procedures during residency through direct patient care. However, there are notable challenges in optimizing how residents are trained in cosmetic and laser dermatology. To address these barriers and elevate the practice of cosmetic dermatology in academic medicine, the Association of Academic Cosmetic Dermatology (AACD) was founded in 2021 as the lead professional society for dermatologists who direct the education of resident trainees in cosmetic and laser dermatology. The AACD,a group of board-certified dermatologists who teach cosmetic and laser dermatology to residents, aims to improve cosmetic dermatology education through collaboration, research, and advocacy.

Background: Sebaceous carcinomas (SC) may be associated with the cancer predisposition syndrome Muir-Torre/Lynch syndrome (MTS/LS), identifiable by SC mismatch repair (MMR) screening; however, there is limited data on MMR status of SC. Objective: To describe the epidemiology of SC, copresentation of other cancers, and population level frequency of MMR screening in SC. Methods: A population-based retrospective cohort study of SC patients in the National Cancer Registration and Analysis Service in England. Results: This study included 1077 SC cases (739 extraocular, 338 periocular). Age-standardized incidence rates (ASIR) were higher in men compared with women, 2.74 (95% CI, 2.52-9.69) per 1,000,000 person-years for men versus 1.47 person-years (95% CI, 1.4-1.62) for women. Of the patients, 19% (210/1077) developed at least one MTS/LS-associated malignancy. MMR immunohistochemical screening was performed in only 20% (220/1077) of SC tumors; of these, 32% (70/219) of tumors were MMR deficient. Limitations: Retrospective design. Conclusions: Incorporation of MMR screening into clinical practice guidelines for the management of SC will increase the opportunity for MTS/LS diagnoses, with implications for cancer surveillance, chemoprevention with aspirin, and immunotherapy treatment targeted to MTS/LS cancers.

Cosmetic dermatology is a key subspecialty of academic dermatology. As such, academic centers are expected to demonstrate excellence in the teaching of cosmetic dermatology skills to trainees, the clinical delivery of cosmetic dermatology services to patients, and the performance of clinical research that advances knowledge and uncovers new therapies in cosmetic dermatology. The Association of Academic Cosmetic Dermatology (AACD), a newly formed medical professional society, includes as its principal aims the support of all of these areas. AACD is comprised of group of board-certified dermatologists who teach cosmetic and laser dermatology at US dermatology residency programs. An expert panel constituted by the AACD recently convened a workshop to review gaps pertaining to academic cosmetic dermatology. This panel considered needs and potential corrective initiatives in three domains: resident education, patient experience, and clinical research. The work of the panel was used to develop a roadmap, which was adopted by consensus, and which will serve to guide the AACD moving forward.

Pyoderma gangrenosum (PG) is a sterile neutrophilic dermatosis manifesting as painful inflammatory plaques and ulcers, frequently associated with inflammatory bowel disease, rheumatoid arthritis, myelodysplastic syndrome, and acute myeloid leukemia.1 We present a case of a young woman with a novel mutation in NFkB1 who experienced common variable immunodeficiency (CVID) and severe recurrent PG episodes.

Background Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous sarcoma, which has been reported in pregnancy. This case series reports the clinical and histopathological findings of DFSP in pregnancy. Methods Eighteen cases of DFSP, including six unreported cases and 12 cases from the literature, were identified. Age, anatomic location, tumor size, changes in tumor characteristics during pregnancy, histopathological features, and treatment were recorded. Follow-up data, when available, were noted. Results The average age of the cohort was 30.6 years (range 19-38). Ten tumors (55.6%) were located on the trunk, four (22.2%) on the head and neck, three (16.7%) on the extremities, and one (5.6%) in the genitalia. Most tumors demonstrated features of conventional DFSP (12/18, 66.7%), while the remaining were identified as DFSP with fibrosarcomatous (FS) change (3/18, 16.7%), atrophic DFSP (2/18, 11.1%), and myxoid DFSP (1/18, 5.6%). Treatment was reported in 17 cases, at least nine of which were treated postpartum. Ten patients were treated with excision, while seven underwent Mohs micrographic surgery. Three patients recurred on follow-up, one with local recurrence and two with distant metastasis. Conclusions DFSP can undergo enlargement or change in size or color in pregnancy, possibly mediated by hormones. While the majority of cases in this series represented conventional DFSP, unusual clinical and histopathological variants were also present. Treatment in most cases can be safely delayed until after delivery, but recurrent or very large tumors may require treatment prepartum. Close monitoring for recurrence or metastasis is advised.

Keratoacanthomas (KAs) are fast-growing tumors and can be difficult to distinguish from squamous cell carcinomas (SCCs). Most KAs are sporadic, but KAs may also arise following traumatic procedures. We report the case of a 94-year-old male who developed multiple KAs following surgical excision of an SCC on the right lower extremity. The patient declined additional procedures including biopsy, surgery, or intralesional therapy. He was started on 5% topical FU using a 2 week on, 2 week off regimen for 16 weeks with resolution of disease. No recurrence was noted at 13 months. Topical 5-FU is a conservative, non-invasive treatment for post-traumatic KAs that is particularly suitable in the elderly, in whom the risks and morbidity from surgical or other non-invasive approaches are worth considering.

Verrucous candidiasis (VC) of the oral mucosa can present with pseudocarcinomatous hyperplasia, often confused with squamous cell carcinoma (SCC). Here, we describe a case of florid VC secondary to fluconazole-resistant Candida albicans and report an initial significant response to oral posaconazole and surgical excisions. However, after 12 months of close follow-up, the patient's VC progressed to frank SCC, demonstrating the malignant potential of refractory VC cases.

Traditionally, second intent healing (SIH) in the periocular region is reserved for small and/or concave defects, particularly those located on the medial canthus. The purpose of this study was to identify factors impacting outcomes of SIH for periocular tumors following Mohs micrographic surgery (MMS). Retrospective analysis was performed of all periocular lesions treated with MMS followed by SIH from a single academic surgical center over a 5-year period. Data regarding tumor characteristics and follow-up was recorded. The modified Manchester scale was utilized to evaluate scar outcomes. Of the 39 tumors included, 14 (35.9%) were located on the lower eyelid, 12 (30.8%) on the upper eyelid, 6 (15.4%) on the lateral canthus, and 7 (17.9%) on the medial canthus. Involvement of the eyelid margin was seen in 11 (28.2%) of cases. The average defect diameter and area were 1.3 cm and 1.04 cm-squared. Twenty-three cases (59.0%) healed with optimal results. Larger defects were significantly associated with poorer outcomes of SIH (odds ratio 0.205, p = 0.017 by multivariate analysis). Anatomic location, involvement of the lid margin, age, and follow-up interval were not significant factors; however, medial canthus defects were least likely to heal with optimal results. On average, medial canthal lesions were larger in size (mean diameter 1.76 cm, mean area 1.97 cm-squared). This retrospective study suggests that periorbital defects in all locations with area less than 1.04 cm2 heal well by SIH. In this cohort, larger lesions on the medial canthus healed with worse outcomes.

Extramammary Paget disease (EMPD) is a frequently recurring malignant neoplasm with metastatic potential that presents in older adults on the genital, perianal, and axillary skin. Extramammary Paget disease can precede or occur along with internal malignant neoplasms.To develop recommendations for the care of adults with EMPD.A systematic review of the literature on EMPD from January 1990 to September 18, 2019, was conducted using MEDLINE, Embase, Web of Science Core Collection, and Cochrane Libraries. Analysis included 483 studies. A multidisciplinary expert panel evaluation of the findings led to the development of clinical care recommendations for EMPD.The key findings were as follows: (1) Multiple skin biopsies, including those of any nodular areas, are critical for diagnosis. (2) Malignant neoplasm screening appropriate for age and anatomical site should be performed at baseline to distinguish between primary and secondary EMPD. (3) Routine use of sentinel lymph node biopsy or lymph node dissection is not recommended. (4) For intraepidermal EMPD, surgical and nonsurgical treatments may be used depending on patient and tumor characteristics, although cure rates may be superior with surgical approaches. For invasive EMPD, surgical resection with curative intent is preferred. (5) Patients with unresectable intraepidermal EMPD or patients who are medically unable to undergo surgery may receive nonsurgical treatments, including radiotherapy, imiquimod, photodynamic therapy, carbon dioxide laser therapy, or other modalities. (6) Distant metastatic disease may be treated with chemotherapy or individualized targeted approaches. (7) Close follow-up to monitor for recurrence is recommended for at least the first 5 years.Clinical practice guidelines for EMPD provide guidance regarding recommended diagnostic approaches, differentiation between invasive and noninvasive disease, and use of surgical vs nonsurgical treatments. Prospective registries may further improve our understanding of the natural history of the disease in primary vs secondary EMPD, clarify features of high-risk tumors, and identify superior management approaches.

Reconstruction of nasal defects secondary to Mohs micrographic surgery (MMS) presents particular challenges related to the complex topography, skin quality, tissue laxity, and functional and aesthetic concerns of the region. Factors affecting outcomes resulting from second intent healing (SIH) on the nose have not been well described. The purpose of the study was to identify factors impacting outcomes of SIH for nasal tumors following MMS. Retrospective analysis was performed of all nasal lesions treated with MMS followed by SIH from a single surgical center over a 1.5-year period. Ninety-six cases were included. Chart review was performed, and data were collected including age, gender, nasal site, tumor type, defect size, depth, and number of MMS stages. Pre- and post-operative follow-up photographs were available for all cases. All five authors evaluated the photographs using the modified Manchester scar scale. Analysis was then conducted to identify features associated with good outcomes. Of the 96 tumors, 39 lesions (40.6%) were located on the nasal tip (including supratip), 32 (33.3%) on the ala/alar groove, 17 (17.7%) on the sidewall, and 8 (8.3%) on the dorsum. The average defect size was 0.83 cm

Traditionally, second intent healing (SIH) in the periocular region is reserved for small and/or concave defects, particularly those located on the medial canthus.The purpose of this study was to identify factors impacting outcomes of SIH for periocular tumors following Mohs micrographic surgery (MMS).Retrospective analysis was performed of all periocular lesions treated with MMS followed by SIH from a single academic surgical center over a 5-year period. Data regarding tumor characteristics and follow-up was recorded. The modified Manchester scale was utilized to evaluate scar outcomes.Of the 39 tumors included, 14 (35.9%) were located on the lower eyelid, 12 (30.8%) on the upper eyelid, 6 (15.4%) on the lateral canthus, and 7 (17.9%) on the medial canthus. Involvement of the eyelid margin was seen in 11 (28.2%) of cases. The average defect diameter and area were 1.3 cm and 1.04 cm-squared. Twenty-three cases (59.0%) healed with optimal results. Larger defects were significantly associated with poorer outcomes of SIH (odds ratio 0.205, p = 0.017 by multivariate analysis). Anatomic location, involvement of the lid margin, age, and follow-up interval were not significant factors; however, medial canthus defects were least likely to heal with optimal results. On average, medial canthal lesions were larger in size (mean diameter 1.76 cm, mean area 1.97 cm-squared).This retrospective study suggests that periorbital defects in all locations with area less than 1.04 cm

Psoriasis is a chronic inflammatory T cell–mediated condition that affects approximately 1% of children. Of the risk factors, obesity is associated with higher frequency and severity of disease.1 Although most children have mild to moderate disease and generally respond well to topical treatment or phototherapy, those with severe disease require systemic treatment. Until recently in the United States, etanercept was the only approved biologic agent for pediatric patients aged 4 years and older with moderate to severe psoriasis; however, data from adults suggests that it is less efficacious than the other available biologic medications. In Europe, adalimumab is also approved for psoriasis for patients aged 4 years and older. Ustekinumab was recently approved for the treatment of psoriasis in pediatric patients aged 12 and older, providing another on-label therapeutic option for adolescents.2, 3 In refractory cases, however, alternative treatment options often need to be pursued. Here we present a case of severe, recalcitrant psoriasis in a child that responded to guselkumab.

Generation of large numbers of dendritic cells (DC) for research or immunotherapeutic purposes typically involves in vitro conversion of murine bone marrow precursors or human blood monocytes to DC via cultivation with supraphysiologic concentrations of cytokines such as GM-CSF and IL-4 for up to 7 days. Alternatively, our group has recently established a new approach, based on the underlying mechanism of action of a widely used cancer immunotherapy termed Extracorporeal Photochemotherapy (ECP). Our method of rapid and cytokine-free production of therapeutically relevant DC populations, leveraging the innate physiologic programs likely responsible for DC differentiation from blood monocytes in vivo, potentially offers a novel, inexpensive, and easily accessible source of DC for clinical and research uses. This approach involves ex vivo physiologic reprogramming of blood monocytes to immunologically tunable dendritic antigen-presenting cells, which we term "phDC," for physiological DC. To facilitate access and utilization of these new DC populations by the research community, in this chapter, we describe the use of a scaled-down version of the clinical ECP leukocyte-treatment device termed the Transimmunization (TI) chamber or plate, suitable for processing both mouse and human samples. We highlight the methodological sequences necessary to isolate mouse or human peripheral blood mononuclear cell (PBMC) from whole blood, and to expose those PBMC to the TI chamber for facilitating monocyte activation and conversion to physiological DC (phDC) through interaction with blood proteins and activated platelets under controlled flow conditions. We then provide sample protocols for potential applications of the generated DC, including their use as vaccinating antigen-presenting cells (APC) in murine in vivo antitumor models, and in human ex vivo T-cell stimulation and antigen cross-presentation assays which mimic clinical vaccination. We additionally highlight the technical aspects of loading mouse or human phDC with tumor-associated antigens (TAA) in the form of peptides or apoptotic tumor cells. We provide a simple and clinically relevant means to reprogram blood monocytes into functional APC, potentially replacing the comparatively expensive and clinically disappointing cytokine-derived DC which have previously dominated the dendritic cell landscape.

Patients with AIDS have increased risk of developing lymphomas, such as anaplastic large cell lymphoma (ALCL), which generally carry a poor prognosis. The DUSP-IRF4 genetic rearrangement in ALCL confers a favourable prognosis in HIV-negative patients; it is unknown how this interacts clinically with HIV/AIDS. A man aged 53 years presented with subcutaneous nodules on the scalp and axillae, and diffuse lymphadenopathy. Biopsy of subcutaneous nodule and lymph node showed large atypical anaplastic lymphocytes which were CD30+ and anaplastic lymphoma kinase-negative, consistent with primary systemic ALCL. In addition, he was found to be HIV-positive and diagnosed with AIDS. Genetic testing of the tissue revealed a DUSP22-IRF4 rearrangement. Complete remission was achieved with HyperCVAD and subsequent brentuximab vedotin monotherapy. We report a case of AIDS-associated primary systemic ALCL with a DUSP22-IRF4 rearrangement. AIDS-associated ALCL is an aggressive lymphoma, with a poor prognosis. However, the presence of the genetic rearrangement, previously unseen in this disease, drastically altered the disease course. This case highlights the value of genetic testing and identifies DUSP22-IRF4-associated ALCL in the setting of HIV-associated lymphoproliferative disorders.

Graft-versus-host disease (GVHD) is a common complication of hematopoietic stem cell transplantation but can rarely occur after solid organ transplants. Small bowel and liver transplants are typically implicated, but solid organ transplant-associated GVHD has also been associated with other organs. We present a 40-year-old diabetic woman who underwent renal followed by pancreatic transplantation over a span of 21 months and ultimately developed acute classic GVHD. The diagnosis proved to be challenging in the context of confounding infections and inconclusive bone marrow and skin biopsy findings. She had multiorgan failure at the time of endoscopic confirmation and died after having minimal response to aggressive immunosuppression.

Sebaceous carcinoma (SC) is a potentially aggressive malignancy of periocular or extraocular skin. It arises sporadically or is associated with Muir–Torre syndrome (MTS). Here, we review three controversial clinical conundra related to the diagnosis and treatment of SC and offer evidence-based recommendations. First, following a diagnosis of SC, deciding which patients to screen for MTS can be challenging. The Mayo MTS Risk Score is a clinical score that incorporates the key cutaneous findings in MTS but relies heavily on personal and family history that may not be available at the time of SC diagnosis, especially in young patients. Young patients, who have extraocular SC and are suspected to have MTS though do not meet criteria by Mayo MTS Risk Score, should have their tumors tested using immunohistochemistry for mismatch repair proteins. Second, sentinel lymph node biopsy (SLNB) is used in periocular SC to evaluate nodal disease. Patient selection is critical for SLNB. Periocular SC stage ≥ T2c (by American Joint Commission on Cancer, 8th edition) may be considered for SLNB given positivity rates over fifteen percent in expert hands. Lastly, treatment of metastatic SC is an area of active investigation. When possible, tumor profiling may be used to select targeted agents. Future research into these three key questions is needed.

Photodynamic therapy (PDT) has been reported as a treatment for cutaneous squamous cell carcinoma in situ (SCCis), but only limited data are available on the effectiveness of PDT with aminolevulinic acid (ALA-PDT).To review the outcomes of SCCis treated with ALA-PDT and examine factors associated with response.A retrospective review identified 58 patients with 68 primary SCCis lesions treated with ALA-PDT and blue light illumination. Patient demographics, lesion features, treatment details, clinical response, and subsequent recurrence were extracted from medical record reviews.On completion of PDT the initial complete response rate was 77.9% and was not associated with the number of PDT treatments. On multivariate analysis factors associated with response were location on the face, tumor diameter2 cm, and longer ALA incubation time. Lesions treated with a maximum incubation time of3 hours had a 53.3% response compared with 84.9% for longer incubation. Subsequent recurrence of SCCis was noted in 7 of 53 cases (13.2%) at a median time of 11.7 months.This was a retrospective study performed at a single institution without systematic follow-up.ALA-PDT may be an effective treatment for selected cases of SCCis. Effectiveness is impacted by anatomic location, tumor diameter, and ALA incubation time.

Sebaceous carcinoma usually occurs in adults older than 60 years, on the eyelid, head and neck, and trunk. In this Review, we present clinical care recommendations for sebaceous carcinoma, which were developed as a result of an expert panel evaluation of the findings of a systematic review. Key conclusions were drawn and recommendations made for diagnosis, first-line treatment, radiotherapy, and post-treatment care. For diagnosis, we concluded that deep biopsy is often required; furthermore, differential diagnoses that mimic the condition can be excluded with special histological stains. For treatment, the recommended first-line therapy is surgical removal, followed by margin assessment of the peripheral and deep tissue edges; conjunctival mapping biopsies can facilitate surgical planning. Radiotherapy can be considered for cases with nerve or lymph node involvement, and as the primary treatment in patients who are ineligible for surgery. Post-treatment clinical examination should occur every 6 months for at least 3 years. No specific systemic therapies for advanced disease can be recommended, but targeted therapies and immunotherapies are being developed.

Extracorporeal photochemotherapy (ECP), or photopheresis, is distinguished by the specificity of the clinically potent immunologic reactions it initiates or regulates. The selectivity of ECP-induced immunoprotection for the malignant clone in cutaneous T cell lymphoma (CTCL), and for the pathogenic clones in allograft rejection and graft-versus-host disease (GVHD), has suggested a central mechanistic role for dendritic antigen presenting cells (DC). Discovery of ECP's induction of monocyte-derived DC, via monocyte signaling by ECP-plate activated platelets, and the absolute dependency of experimental ECP on such induced DC, supports that premise. Herein, we show that ECP-induced DC are capable of stimulating CD8 T cell responses to tumor antigens with which they are loaded. They internalize an antigen-specific melanoma-associated protein then present it onto a class I major histocompatibility, which then stimulates expansion of anti-tumor CD8 T cell populations. We conclude that ECP-induced DC prominently contribute to its initiation of anti-tumor immunity and raise the possibility that the therapy may be applicable to the immunotherapeutic management of a broader spectrum of cancers.

Granulomatous skin diseases are a diverse group of disorders as chronic inflammatory responses to infectious and noninfectious antigens and/or other organic or inorganic materials the immune system is unable to eliminate. The diagnosis of granulomatous diseases relies heavily on clinical and pathological examination; the unifying finding is an inflammatory infiltrate predominantly composed of histiocytes, macrophages, and giant cells, sometimes showing collagen degeneration and caseation necrosis. The clinical manifestations are generally rare and may differ in their incidence and presentation in individuals with heavily pigmented ethnic skin.

Local therapy for in-transit melanoma (ITM) is a treatment alternative for patients who are not good candidates for systemic therapy, regional therapy, or surgical management. In this case report, we describe 3 patients with ITM who were treated with intralesional Bacillus Calmette-Guerin (ILBCG) and/or topical imiquimod. Treatment course was dictated by the clinical response. Patient 1's response to ILBCG monotherapy was not sufficient to cause disease regression; however, transition to topical imiquimod therapy resulted in complete and sustained response. Although patient 2 responded to ILBCG and imiquimod, she developed a hypersensitivity reaction to ILBCG; when topical imiquimod was continued as monotherapy, her clinical response was complete. Patient 3 responded completely to ILBCG monotherapy in injected lesions, but expired shortly thereafter from unrelated disease. Reports like this one are needed to define the success measures of local therapy in the treatment of ITM.

Eruptive melanocytic nevi (EMN) are an unusual phenomenon characterized by the rapid appearance of multiple melanocytic nevi. Whether atypical or benign, EMN are associated with various medications and diseases but not previously with melanoma.1 EMN have been described in internal malignancy, such as prostate cancer, in which it is proposed as a paraneoplastic phenomenon, although the mechanism is unclear.2 One cutaneous phenomenon that arises from primary melanoma is epidermotropic metastatic malignant melanoma (EMMM), whereby malignant cells migrate from the dermal metastasis into the epidermis. Epidermotropic metastases are metachronous with the primary tumor or appear after resection or treatment of the primary disease, and melanoma is no exception.3 Eruptive nevi may be clinically mistaken as EMMM; therefore, making the distinction is important. We report a case of a patient who had 2 concurrent primary melanomas treated with wide local resection and in whom EMN developed, with no signs of EMMM, 8 weeks before diagnosis of widespread metastatic melanoma.

Melanoma is the malignancy with the highest rate of dissemination to the central nervous system once it metastasizes. Until recently, the prognosis of patients with melanoma brain metastases (MBM) was poor. In recent years, however, the prognosis has improved due to high-resolution imaging that facilitates early detection of small asymptomatic brain metastases and early intervention with local modalities such as stereotactic radiosurgery. More recently, a number of systemic therapies have been approved by the Food and Drug Administration for metastatic melanoma, resulting in improved survival for many MBM patients. Registration trials for these newer therapies excluded patients with untreated brain metastases, and a number of studies specifically tailored to this population of patients have been conducted or are underway. Herein, we review contemporary locoregional and systemic therapies and describe the unique challenges posed by treatment of brain metastases, such as radionecrosis, cerebral edema, and pseudoprogression. Since the number of systemic and combined modality clinical trials has increased, we expect that the treatment landscape for patients with melanoma brain metastasis will change dramatically. In addition to ongoing clinical trials, which show great promise, we conclude that our understanding of intracranial metastasis remains quite limited. In addition to inter-disciplinary, multi-modality studies, bench-side work to better understand the process of cerebrotropism is needed to fuel more drug development and further improve outcomes.

Extracorporeal Photochemotherapy (ECP) is a widely applied anti-cancer immunotherapy for patients with cutaneous T cell lymphoma (CTCL). By using apoptotic malignant cells as a source of patient-specific tumor antigen, it enables clinically relevant and curative anti-CTCL immunity, with potential efficacy in other tumors. Currentmethods to track patient-specific responses are tedious, and new methods are needed to assess putative global immunity. We developed a clinically practical method to assess antigen-specific T cell activation that does not rely on knowledge of the particular antigen, thereby eliminating the requirement for patient-specific reagents. In the OT-I transgenic murine system, we quantified calcium flux to reveal early T cell engagement by antigen presenting cells constitutively displaying a model antigenic peptide, ovalbumin (OVA)-derived SIINFEKL. We detected calcium flux in OVA-specific T cells, triggered by specific T cell receptor engagement by SIINFEKL peptide-loaded DC. This approach led to sensitive detection of antigen-specific calcium flux (ACF) down to a peptide-loading concentration of ∼10-3uM and at a frequency of ∼0.1% OT-I cells among wild-type (WT), non-responding cells. Antigen-specific T cells were detected in spleen, lymph nodes, and peripheral blood after adoptive transfer into control recipient mice. Methods like this for assessing therapeutic response are lacking in patients currently on immune-based therapies, such as ECP, where assessment of clinical response is made by delayed measurement of the size of the malignant clone. These findings suggest an early, practical way to measure therapeutically-induced anti-tumor responses in ECP-treated patients that have been immunized against their malignant cells.

A 63-year-old woman with diabetes presented with 8 weeks of proximal muscle weakness and change in bowel habits. Muscle biopsy confirmed myositis, and serological studies were consistent with dermatomyositis (DM), without evidence of overlapping connective tissue disease or malignancy. On day 12 of prednisone therapy and after receiving one dose of IVIG with improvement in muscle strength, the patient developed abdominal pain and was diagnosed with a gastrointestinal (GI) perforation and peritonitis requiring emergent colectomy. The pathology revealed diffuse mucosal ulceration, prominent lymphoplasmacytic infiltration, venous occlusion and arterial hyperplasia. Although GI manifestations due to GI vasculopathy are rare in adult DM and are often a delayed complication, in this patient, it was one of the initial manifestations of this condition. In addition to being a fatal complication, clinicians should be aware of these complications, as immunosuppression used to control the muscular and cutaneous inflammation may not control the GI vasculopathy.

In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1%-2%) than at high prevalence (50%). Unfortunately, low prevalence is characteristic of important search tasks such as airport security and medical screening where miss errors are dangerous. A series of experiments show this prevalence effect is very robust. In signal detection terms, the prevalence effect can be explained as a criterion shift and not a change in sensitivity. Several efforts to induce observers to adopt a better criterion fail. However, a regime of brief retraining periods with high prevalence and full feedback allows observers to hold a good criterion during periods of low prevalence with no feedback.

The malignant cell in melanoma is the melanocyte. Because melanocytes are located in the basal layer of the epidermis, melanoma is most commonly seen on the skin. However, melanoma can also arise on mucosal surfaces such as the oral cavity, the upper gastrointestinal mucosa, the genital mucosa, as well as the uveal tract of the eye and leptomeninges. Melanomas tend to be pigmented but can also present as pink or red lesions. They can mimic benign or other malignant skin lesions. This chapter presents the spectrum of typical and less typical presentations of melanoma, as well as patterns of spread. It is divided into (1) cutaneous lesions; (2) patterns of regional spread, (3) non-cutaneous lesions; and (4) distant metastases.