Full Spectrum of Postnatal Tooth Phenotypes in a Novel Irf6 Cleft Lip Model

Clefting of the lip, with or without palatal involvement (CLP), is associated with a higher incidence of developmental tooth abnormalities, including hypodontia and supernumerary teeth, aberrant crown and root morphologies, and enamel defects, although the underlying mechanistic link is poorly understood. As most CLP genes are expressed throughout the oral epithelium, the authors hypothesized that the expression of CLP genes may persist in the dental epithelium and thus, in addition to their earlier role in labiopalatine development, may play an important functional role in subsequent tooth patterning and amelogenesis. To address this, the authors generated a unique conditional knockout model involving the major CLP gene, Irf6, that overcomes the previously reported perinatal lethality to enable assessment of any posteruption dental phenotypes. A dental epithelium-specific Irf6 conditional knockout (Irf6-cKO) mouse was generated via a Pitx2-Cre driver line. Dental development was analyzed by microcomputed tomography, scanning electron microscopy, histology, immunohistochemistry, and quantitative polymerase chain reaction. Irf6-cKO mice displayed variable hypodontia, occasional supernumerary incisors and molars, as well as crown and root patterning anomalies, including peg-shaped first molars and taurodontic and C-shaped mandibular second molars. Enamel density was reduced in preeruption Irf6-cKO mice, and some shearing of enamel rods was noted in posteruption incisors. There was also rapid attrition of Irf6-cKO molars following eruption. Histologically, Irf6-cKO ameloblasts exhibited disturbances in adhesion and polarity, and delayed enamel formation was confirmed immunohistochemically. Altered structure of Hertwig's epithelial root sheath was also observed. These data support a role for IRF6 in tooth number, crown and root morphology and amelogenesis that is likely due to a functional role of Irf6 in organization and polarity of epithelial cell types. This data reinforce the notion that various isolated tooth defects could be considered part of the CLP spectrum in relatives of an affected individual.

Cutaneous autoimmune effects in the setting of therapeutic immune checkpoint inhibition for metastatic melanoma

Therapeutic immune checkpoint blockade for metastatic melanoma has been associated with vitiligo, pruritus and morbilliform eruptions. Reports of other autoimmune skin disease in this setting are rare. We sought to expand the spectrum of cutaneous immune-mediated effects related to immune checkpoint inhibitor therapy. In this report, we describe two unusual cutaneous reactions related to checkpoint inhibitor therapy, namely bullous pemphigoid (BP) and dermatitis herpetiformis. The development of BP and dermatitis herpetiformis in the context of checkpoint inhibitor therapy is consistent with previous investigations supporting the importance of effector and regulatory T cells in the pathogenesis of these diseases.

Evaluation of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) classification scheme for diagnosis of cutaneous melanocytic neoplasms: Results from the International Melanoma Pathology Study Group

BACKGROUND

Pathologists use diverse terminology when interpreting melanocytic neoplasms, potentially compromising quality of care.

OBJECTIVE

We sought to evaluate the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) scheme, a 5-category classification system for melanocytic lesions.

METHODS

Participants (n = 16) of the 2013 International Melanoma Pathology Study Group Workshop provided independent case-level diagnoses and treatment suggestions for 48 melanocytic lesions. Individual diagnoses (including, when necessary, least and most severe diagnoses) were mapped to corresponding MPATH-Dx classes. Interrater agreement and correlation between MPATH-Dx categorization and treatment suggestions were evaluated.

RESULTS

Most participants were board-certified dermatopathologists (n = 15), age 50 years or older (n = 12), male (n = 9), based in the United States (n = 11), and primary academic faculty (n = 14). Overall, participants generated 634 case-level diagnoses with treatment suggestions. Mean weighted kappa coefficients for diagnostic agreement after MPATH-Dx mapping (assuming least and most severe diagnoses, when necessary) were 0.70 (95% confidence interval 0.68-0.71) and 0.72 (95% confidence interval 0.71-0.73), respectively, whereas correlation between MPATH-Dx categorization and treatment suggestions was 0.91.

LIMITATIONS

This was a small sample size of experienced pathologists in a testing situation.

CONCLUSION

Varying diagnostic nomenclature can be classified into a concise hierarchy using the MPATH-Dx scheme. Further research is needed to determine whether this classification system can facilitate diagnostic concordance in general pathology practice and improve patient care.

Presentation of Acute Megakaryoblastic Leukemia Associated with a GATA-1 Mutation Mimicking the Eruption of Transient Myeloproliferative Disorder

Children with trisomy 21 are prone to developing hematologic disorders, including transient myeloproliferative disorder (TMD) and acute megakaryoblastic leukemia (AMKL). The papulovesicular eruption of TMD provides an important clue to the diagnosis. In contrast, AMKL rarely has associated cutaneous findings. We report the case of a 22-month-old child with trisomy 21 who presented with the acute onset of diffusely scattered and crusted papules, plaques, and vesicles. A thorough infectious evaluation was negative and the patient was unresponsive to empiric antibiotic and antiinflammatory therapies. Complete blood count (CBC) was notable for mild pancytopenia, with a normal peripheral smear. Two weeks later he was reassessed and found to have a population of blasts on repeat CBC. Subsequent evaluation ultimately led to a diagnosis of AMKL. This is the first reported case of a cutaneous eruption in a young child with Down syndrome and transformed AMKL. When children with trisomy 21 present with the acute onset of crusted papules and vesicles that cannot be accounted for by an infectious etiology, a diagnosis of AMKL should be considered even in the absence of a history of TMD.

Nodular scleroderma in a patient with chronic hepatitis C virus infection: a coexistent or causal infection?

Nodular scleroderma is a rare form of scleroderma that may occur systemically or locally. The pathogenesis of this variant is unknown. We report the case of a 63-year-old woman with systemic scleroderma and chronic hepatitis C virus (HCV) infection who had numerous papules and nodules on the neck and trunk. Skin biopsies from her lesions revealed characteristic findings of scleroderma. This case not only depicts the rare entity of nodular scleroderma but demonstrates the association of HCV infection with systemic autoimmune diseases such as scleroderma.

Photo-distributed lichenoid eruption secondary to direct anti-viral therapy for hepatitis C

Novel direct anti-viral agents are emerging as effective treatments for hepatitis C virus (HCV) and provide an alternative to the year-long standard therapy with interferon and ribavirin. However, cutaneous side effects from these new medications, including rash, pruritus and photosensitivity, are among the most commonly reported adverse events and have resulted in therapy discontinuation in some cases. Here, we report two cases of a photo-distributed lichenoid eruption that occurred within 1  month of starting anti-viral therapy with simeprevir and sofosbuvir without interferon or ribavirin. This report provides the first histologic description of the cutaneous eruption associated with direct anti-viral therapy for HCV and highlights the importance of recognizing and treating the often intolerable dermatologic side effects of these novel medications, the incidence of which is likely to increase as direct anti-viral agents may become the standard of care for HCV.

Rare angioinvasive fungal infection in association with leukemia cutis

Leukemia cutis (LC) is characterized by the infiltration of malignant neoplastic leukocytes or their precursors into the skin and is most often seen in conjunction with systemic leukemia. Patients with LC frequently are in a relative or absolute immunocompromised state. We report the case of a 52-year-old man with primary refractory acute myelogenous leukemia (AML) following allogeneic stem cell transplant (SCT) who presented with a progressive reddish purple nodule with surrounding erythema and central necrosis in the setting of leukocytosis and possible fungal pneumonia. Histopathologic examination revealed an ulcerated dense diffuse dermal infiltrate of large atypical lymphocytes consistent with LC and septate hyphae with acute-angle branching in the dermal blood vessels. Cultures from a biopsied lesion grew Paecilomyces species, a rare but emerging opportunistic infection, despite the patient being on antifungal prophylaxis. This novel report of a rare angioinvasive infection occurring within a lesion of LC supports the need to maintain a high index of suspicion for invasive infection in patients with hematologic malignancy, even those on antifungal prophylaxis.

Kidney disease among children in sub-Saharan Africa: systematic review

The global burden of kidney disease is increasing, and several etiologies first begin in childhood. Risk factors for pediatric kidney disease are common in Africa, but data regarding its prevalence are lacking. We completed a systematic review of community-based studies describing the prevalence of proteinuria, hematuria, abnormal imaging, or kidney dysfunction among children in sub-Saharan Africa (SSA). Medline and Embase were searched. Five hundred twenty-three references were reviewed. Thirty-two references from nine countries in SSA were included in the qualitative synthesis. The degree of kidney damage and abnormal imaging varied widely: proteinuria 32.5% (2.2-56.0%), hematuria 31.1% (0.6-67.0%), hydronephrosis 11.3% (0.0-38.0%), hydroureter 7.5% (0.0-26.4%), and major kidney abnormalities 0.1% (0.0-0.8%). Serum creatinine was reported in four studies with insufficient detail to identify the prevalence renal dysfunction. A majority of the studies were performed in Schistosoma haematobium endemic areas. A lower prevalence of kidney disease was observed in the few studies from nonendemic areas. Published data on pediatric kidney disease in SSA are highly variable and dependent on S. haematobium prevalence. More community-based studies are needed to describe the burden of pediatric kidney disease, particularly in regions where S. haematobium infection is nonendemic.

Vemurafenib-induced interface dermatitis manifesting as radiation-recall and a keratosis pilaris-like eruption

Vemurafenib is a specific inhibitor of the V600E mutated BRAF protein kinase used for the treatment of unresectable or metastatic melanoma harboring this mutation. Multiple predictable side effects have been described with use of this targeted therapy, and implicate BRAF and mitogen activated protein kinase (MAPK) signaling pathways in their pathogenesis. Herein, we report the novel finding of an interface dermatitis in radiation recall and a keratosis pilaris-like clinical reaction in a patient treated with vemurafenib.

Coxsackievirus A6-induced hand-foot-mouth disease

IMPORTANCE

Hand-foot-mouth disease (HFMD) is an acute, self-limited, highly contagious viral illness that commonly affects children younger than 5 years. It is most typically caused by enterovirus 71 or coxsackievirus A16 and results in asymptomatic infection or mild disease. Immunocompetent adults are rarely affected. Recently, there have been increasing reports of a more severe form of HFMD associated with fevers, joint pains, and widespread painful eruptions. Some of these patients required hospitalization for supportive care. These severe cases were most commonly caused by coxsackievirus A6.

OBSERVATIONS

We describe a 37-year-old white man with widespread, crusted, pruritic papules on the scalp, ears, and face and a purpuric and targetoid painful vesicular eruption on his hands and feet, with associated fevers, neurologic symptoms, and arthritis, who required hospitalization for supportive care. His infection with coxsackievirus A6 was confirmed based on polymerase chain reaction from his oral mucosa and cutaneous vesicle fluid.

CONCLUSIONS AND RELEVANCE

Dermatologists should be familiar with the severe variant of HFMD caused by coxsackievirus A6, include it in their differential diagnosis of acute febrile blistering diseases, and be aware that certain patients may require hospitalization.

Changing pigmentation in a solitary scalp lesion

A healthy 66 year-old man presented with a complaint of changes within a nodule on the scalp, which had first appeared over 10 years prior. He had no previous history of skin cancer. On physical examination a solitary, asymmetric, purple-black nodule with irregular borders was identified on the right vertex of his scalp. The remainder of his examination did not reveal any additional lesions.

Reliability and convergent validity of the cutaneous sarcoidosis activity and morphology instrument for assessing cutaneous sarcoidosis

IMPORTANCE

A validated scoring system is essential to assess the effect of therapeutic interventions on a disease. The instrument introduced here captures sarcoidosis disease activity in a reliable, reproducible manner, which will help standardize clinical trial outcomes and allow comparative efficacy studies in the future and may help lead to more robust data regarding the effect of different treatments on cutaneous sarcoidosis.

OBJECTIVE

To assess the reliability and convergent validity of the Cutaneous Sarcoidosis Activity and Morphology Instrument (CSAMI) and Sarcoidosis Activity and Severity Index (SASI) for evaluating cutaneous sarcoidosis outcomes.

DESIGN AND SETTING

Cross-sectional study evaluating cutaneous sarcoidosis disease severity using CSAMI, SASI, and Physician's Global Assessment (PGA) as reference in the dedicated cutaneous sarcoidosis clinic of a teaching hospital.

PARTICIPANTS

Eight dermatologists evaluating cutaneous sarcoidosis in 11 patients.

INTERVENTION

Evaluation using the study instruments.

MAIN OUTCOMES AND MEASURES

Primary outcomes included interrater and intrarater reliability and convergent validity; secondary outcomes, correlation with quality-of-life measures and time required for completion.

RESULTS

All instruments demonstrated good to excellent intrarater reliability. Interrater reliability was excellent for CSAMI Activity scores (intraclass correlation coefficient, 0.82 [95% CI, 0.66-0.94]) and fair to poor for CSAMI Damage scores (0.42 [0.21-0.72]), modified Facial SASI (0.40 [0.17-0.72]), and PGA scores (0.40 [0.18-0.70]). CSAMI Activity and Damage scores and modified Facial SASI all demonstrated convergent validity with statistically significant correlations with PGA scores. Trends for correlations were seen between CSAMI scores and specific Skindex-29 quality-of-life domains. Although CSAMI required longer time to complete than SASI, both were scored within adequate time for use in clinical trials.

CONCLUSIONS AND RELEVANCE

CSAMI appears to be a reliable and valid outcome instrument to measure cutaneous sarcoidosis and may capture a wide range of body surface and cutaneous morphologic types. This instrument can be adopted into clinical practice and clinical trials to allow physicians to assess the intensity of their patients' cutaneous sarcoidosis disease activity. Widespread use of one metric for disease severity assessment can help standardize the evaluation of the effect of various treatments on the disease. Future research is necessary to demonstrate its sensitivity to change and to confirm its correlation with quality-of-life measures.

Shiitake dermatitis: a report of 3 cases and review of the literature

Shiitake mushroom-induced toxicoderma, or shiitake dermatitis, is a widely recognized phenomenon in Japan, China, and Korea but only recently has been reported outside of Asia. Affected individuals develop a characteristic pattern of whiplike, linear, erythematous wheals within 1 to 2 days after consumption of raw or cooked shiitake mushrooms. Lentinan, a polysaccharide component of shiitake mushrooms with antitumor properties, is thought to instigate a toxic reaction, resulting in the appearance of a rash. Shiitake dermatitis is self-limited and typically resolves within days to weeks of its appearance.

NRAS and BRAF mutations in atypical melanocytic lesions arising in melanoma patients treated with vemurafenib

9017

Background: BRAF inhibition with targeted therapy has demonstrated improved overall survival in patients with BRAF mutant melanoma. The use of the selective BRAF inhibitors vemurafenib and dabrafenib are associated with a range of known and predictable cutaneous side effects, including squamous cell carcinomas often associated with RAS mutations. Preclinical evidence indicates that BRAF inhibitors may give rise to non-melanoma tumors by promoting MAPK activation in the tissues that lack mutant BRAF. Here we report atypical melanocytic lesions arising in patients treated with the BRAF inhibitor vemurafenib. Methods: To characterize the mutations of both the melanoma tumors and the atypical melanocytic lesions arising in patients with BRAF V600E/K melanoma treated with vemurafenib, a custom Sequenom panel designed to detect 74 mutations in 12 genes known to play a role in the pathogenesis of melanoma was applied to both melanoma and atypical melanocytic lesions for each patient. Results: We observed a total of six atypical melanocytic lesions (melanoma in situ and severely dysplastic nevi) in three patients undergoing treatment with vemurafenib. Mutations analysis in both pre-treatment tumor samples and on-treatment melanocytic lesions was feasible in two of the three patients. One patient with BRAF V600E metastatic melanoma developed two new melanoma in situ lesions while on vemurafenib, diagnosed 10 and 23 weeks after starting vemurafenib. Both on-treatment melanoma in situ lesions were found by Sequenom analysis to be BRAF wild-type, with a NRAS Q16R detected in one of the two lesions. Another patient’s pre-treatment primary melanoma demonstrated synchronous BRAF kinase domain mutations V600K and G466A, and CTNNB1 D32E mutation; a severely dysplastic nevus which arose after 25 weeks on vemurafenib in this patient showed only a BRAFG466A mutation. Conclusions: We identified an NRAS mutation and a rare BRAF kinase domain mutation in atypical melanocytic lesions that arose in patients treated with vemurafenib. Further studies are warranted to demonstrate a causal relationship between BRAF inhibition and the development or accelerated growth of atypical melanocytic lesions.

Disseminated microsporidiosis in an immunosuppressed patient

We report a case of disseminated microsporidiosis in a patient with multiple myeloma who had received an allogeneic stem cell transplant requiring substantial immunosuppression. The causative organism was identified as Tubulinosema acridophagus, confirming this genus of microsporidia as a novel human pathogen.

High phosphate feeding promotes mineral and bone abnormalities in mice with chronic kidney disease

BACKGROUND

Chronic kidney disease-mineral bone disorder (CKD-MBD) is a systemic syndrome characterized by imbalances in mineral homeostasis, renal osteodystrophy (ROD) and ectopic calcification. The mechanisms underlying this syndrome in individuals with chronic kidney disease (CKD) are not yet clear.

METHODS

We examined the effect of normal phosphate (NP) or high phosphate (HP) feeding in the setting of CKD on bone pathology, serum biochemistry and vascular calcification in calcification-prone dilute brown non-agouti (DBA/2) mice.

RESULTS

In both NP and HP-fed CKD mice, elevated serum parathyroid hormone and alkaline phosphatase (ALP) levels were observed, but serum phosphorus levels were equivalent compared with sham controls. CKD mice on NP diet showed trabecular alterations in the long bone consistent with high-turnover ROD, including increased trabecular number with abundant osteoblasts and osteoclasts. Despite trabecular bone and serum biochemical changes, CKD/NP mice did not develop vascular calcification. In contrast, CKD/HP mice developed arterial medial calcification (AMC), more severe trabecular bone alterations and cortical bone abnormalities that included decreased cortical thickness and density, and increased cortical porosity. Cortical bone porosity and trabecular number strongly correlated with the degree of aortic calcification.

CONCLUSIONS

HP feeding was required to induce the full spectrum of CKD-MBD symptoms in CKD mice.