Erythema elevatum diutinum mimicking extensive keloids; quiz 386

GOAL

To describe a case of erythema elevatum diutinum (EED) that clinically mimicked extensive keloids.

OBJECTIVES

Upon completion of this activity, dermatologists and general practitioners should be able to: 1. Describe the clinical presentation and lesion appearance in EED. 2. Discuss the electron microscopic and laboratory findings of EED. 3. Outline treatment options for EED. CME: This article has been peer reviewed and approved by Michael Fisher, MD, Professor of Medicine, Albert Einstein College of Medicine.

REVIEW DATE

April 2001. This activity has been planned and implemented in accordance with the Essentials and Standards of the Accreditation Council for Continuing Medical Education through the joint sponsorship of Albert Einstein College of Medicine and Quadrant HealthCom, Inc. The Albert Einstein College of Medicine is accredited by the ACCME to provide continuing medical education for physicians. Albert Einstein College of Medicine designates this educational activity for a maximum of 1.0 hour in category 1 credit toward the AMA Physician's Recognition Award. Each physician should claim only those hours of credit that he/she actually spent in the educational activity. This activity has been planned and produced in accordance with ACCME Essentials.

Validation of DNA-based HLA-A and HLA-B testing of volunteers for a bone marrow registry through parallel testing with serology

A total of 42,160 individuals were typed for HLA-A and HLA-B by both serology and PCR-based typing. The HLA assignments included all of the known serological equivalents. The majority of the individuals (99.9%) were from U.S. minority population groups. The serologic typing was performed between 1993 and 1997 at the time of recruitment for the National Bone Marrow Program (NMDP) registry. The polymerase chain reaction (PCR)-based typing was carried out in two phases. In phase I, DNA typing was performed by PCR using sequence-specific oligonucleotide probes (PCR-SSOP) or PCR using sequence-specific primers (PCR-SSP) without knowledge of the serologic assignments. Discrepancies were identified between the serologic and DNA assignments in 24% of the volunteers (8% of volunteers differed for only HLA-A assignments, 13% for HLA-B, and 3% for both HLA-A and -B) and a potential explanation was assigned each discrepant serology/DNA pair. In phase II, a random sampling scheme was used to select a statistically significant number of individuals for repeat DNA typing from each of these categories. The categories included antigens missed by serology, nonexpressed (null) alleles, PCR amplification failures, misassignment of antigens and nomenclature issues. Only a single individual was found to carry a null allele. DNA-based testing correctly typed nearly 99% of the donors at HLA-A, more than 98% at HLA-B, and more than 97% at both HLA-A and -B validating this methodology for registry typing.

Complex HLA-DR and -DQ interactions confer risk of narcolepsy-cataplexy in three ethnic groups

Human narcolepsy-cataplexy, a sleep disorder associated with a centrally mediated hypocretin (orexin) deficiency, is tightly associated with HLA-DQB1*0602. Few studies have investigated the influence that additional HLA class II alleles have on susceptibility to this disease. In this work, 1,087 control subjects and 420 narcoleptic subjects with cataplexy, from three ethnic groups, were HLA typed, and the effects of HLA-DRB1, -DQA1, and -DQB1 were analyzed. As reported elsewhere, almost all narcoleptic subjects were positive for both HLA-DQA1*0102 and -DQB1*0602. A strong predisposing effect was observed in DQB1*0602 homozygotes, across all ethnic groups. Relative risks for narcolepsy were next calculated for heterozygous DQB1*0602/other HLA class II allelic combinations. Nine HLA class II alleles carried in trans with DQB1*0602 were found to influence disease predisposition. Significantly higher relative risks were observed for heterozygote combinations including DQB1*0301, DQA1*06, DRB1*04, DRB1*08, DRB1*11, and DRB1*12. Three alleles-DQB1*0601, DQB1*0501, and DQA1*01 (non-DQA1*0102)-were found to be protective. The genetic contribution of HLA-DQ to narcolepsy susceptibility was also estimated by use of lambda statistics. Results indicate that complex HLA-DR and -DQ interactions contribute to the genetic predisposition to human narcolepsy but that additional susceptibility loci are also most likely involved. Together with the recent hypocretin discoveries, these findings are consistent with an immunologically mediated destruction of hypocretin-containing cells in human narcolepsy-cataplexy.

Acantholytic dermatosis of the vulvocrural area

Acantholytic dermatosis of the vulvocrural area is a rare skin disorder characterized by solitary or multiple skin-colored to white, smooth papules or plaques. Histopathological features of both Hailey-Hailey disease and Darler's disease are present. There is acantholysis, which may involve the full thickness of the epidermis, and dyskeratosis with corps ronds and grains. There may be marked hyperkeratosis and focal parakeratosis. We report a case of this rare disease and discuss its differential diagnosis and treatment.

Multicentric reticulohistiocytosis with neurofibroma-like nodules

We describe a patient with multicentric reticulohistiocytosis (MR), who presented with 2 different clinical types of lesions. Some were characteristic for MR in that they were deeply set, small, firm papules. Many others were larger, soft, and even sessile, like neurofibromas. Histopathologic features of both types of lesions revealed MR. To our knowledge, this is the first report of lesions of MR mimicking neurofibromas.

Unilateral atrophic skin lesion with features of atrophoderma vermiculatum: a variant of the epidermal nevus syndrome?

We report a case of atrophic skin lesions similar to atrophoderma vermiculatum with unilateral distribution in a patient with an ipsilateral cataract, transient ipsilateral alopecia, and a seizure disorder. Atrophoderma vermiculatum may be a cutaneous marker for various internal abnormalities.

Mutational analysis and NMR studies of the death domain of the tumor necrosis factor receptor-1

Tumor necrosis factor receptor-1 (TNFR-1) death domain (DD) is the intracellular functional domain responsible for the receptor signaling activities. To understand the transduction mechanism of TNFR-1 signaling we performed structural and functional analysis of the TNFR-DD. The secondary structure of the TNFR-DD shows that it consists of six anti-parallel alpha-helices. The determination of the topological fold and an extensive mutagenesis analysis revealed that there are two opposite faces that are involved in self-association and interaction with the TRADD death domain. Interestingly, the same critical residues in TNFR-DD are involved in both interactions. There is a good correlation between the binding activities of the mutant proteins and their cytotoxic activities. These results provide important insight into the molecular interactions mediating TNFR-DD self-association and subsequent recruitment of TRADD in the signaling activity of TNFR-1.

Calciphylaxis

Calciphylaxis is a rare, life-threatening condition of widespread metastatic calcification most commonly seen in the setting of end-stage renal disease. The etiology of calciphylaxis is not well described, though there are several hypotheses. Cutaneous lesions are characteristically found on the abdomen, buttocks, or thighs as reticulated, painful, purple plaques that often undergo ulceration and may serve as a portal of entry for potentially life-threatening infectious agents. Histology reveals medial calcification with intimal proliferation involving small vessels in the subcutaneous fat, associated with a lymphohistiocytic infiltrate of the affected lobules. Treatment, including phosphate binders and parathyroidectomy, is not universally effective. We present one case of calciphylaxis and discuss the clinical features, pathophysiology, histology, and treatment of the condition.

Computer palms

We describe a new occupation-related skin finding in 2 computer programmers and discuss its characteristics and causes.

Solution structure of N-TRADD and characterization of the interaction of N-TRADD and C-TRAF2, a key step in the TNFR1 signaling pathway

TRADD is a multifunctional signaling adaptor protein that is recruited to TNFR1 upon ligand binding. The C-terminal of TRADD comprises the "death domain" that is responsible for association of TNFR1 and other death domain-containing proteins such as FADD and RIP. The N-terminal domain (N-TRADD) promotes the recruitment of TRAF2 to TNFR1 by binding to the C-terminal of TRAF2, leading to the activation of JNK/AP1 and NF-kappa B. The solution structure of N-TRADD was determined, revealing a novel protein fold. A combination of NMR, BIAcore, and mutagenesis experiments was used to help identify the site of interaction of N-TRADD with C-TRAF2, providing a framework for future attempts to selectively inhibit the TNF signaling pathways.