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Anetodermic pilomatrixomas: A case series. SKIN HEALTH AND DISEASE 2023; 3:e284. [PMID: 38047261 PMCID: PMC10690670 DOI: 10.1002/ski2.284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/13/2023] [Accepted: 08/25/2023] [Indexed: 12/05/2023]
Abstract
Pilomatrixoma is a benign hair follicle tumour. Anetodermic changes overlying pilomatrixoma are rare. The aim of this study is to evaluate a case series of patients with a clinical diagnosis of anetodermic pilomatrixoma presenting to our Dermatology Department over a 5-year period. Eight cases were identified. The median age of onset was 21 years. All cases presented on the upper limbs and trunk with a solitary rapidly evolving tumour, tender on palpation. They had an erythematous protuberant appearance with a wrinkled and atrophic surface. Underlying pilomatrixomas were firm measuring 1-5 cm. Simple excision was carried out in seven cases without postoperative complications. In conclusion, anetodermic pilomatrixoma is a rare variant of this tumour, occurring more frequently on the upper body. It presents with identifiable features and should be differentiated from other skin tumours. Surgical removal is usually the gold standard treatment.
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An unusual case of longstanding mammary Paget disease presenting with reticulated skin changes. Clin Exp Dermatol 2021; 46:748-750. [PMID: 33400312 DOI: 10.1111/ced.14553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 11/29/2022]
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Unusual clustered papules on the lower back of a 13-year-old. Pediatr Dermatol 2020; 37:e89-e90. [PMID: 33283925 DOI: 10.1111/pde.14380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/09/2020] [Accepted: 08/25/2020] [Indexed: 11/26/2022]
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Tattoo granulomas with associated uveitis responding to ocular treatment with dexamethasone 0.1% drops. Clin Exp Dermatol 2020; 45:740-742. [PMID: 32286707 DOI: 10.1111/ced.14237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2020] [Indexed: 11/29/2022]
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Global and mitosis-specific interobserver variation in mitotic count scoring and implications for malignant melanoma staging. Histopathology 2020; 76:803-813. [PMID: 31879972 DOI: 10.1111/his.14052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/18/2019] [Accepted: 12/21/2019] [Indexed: 11/30/2022]
Abstract
AIMS Staging is the gold standard for predicting malignant melanoma outcome but changes in its criteria over time indicate ongoing evolution. One notable recent change from the 8th edition of the American Joint Committee on Cancer (AJCC) staging manual was removal of mitotic count. We explore the extent to which this feature is limited by interobserver error in order to find ways to improve its fitness for use should it be revisited in future staging versions. METHODS AND RESULTS In a cohort of 476 patients with melanoma ≤1.0 mm, a mitotic count of 0 versus 1 was significant for metastasis-free survival, but not melanoma-specific or overall survival. In 10 melanomas that were 0.9-1.0 mm thick, the mitotic count intraclass correlation coefficient for histopathologists was 0.58 (moderate agreement). Uniquely, we also assessed agreement for specific putative mitotic figures, identifying precise reasons why specific mitotic figures qualified for scoring or elimination. A kappa score was 0.54 (moderate agreement). We also gathered data on other staging features. Breslow thickness had an intraclass correlation coefficient of 0.41 (moderate agreement) and there was a systematic difference between histopathologists among cases (P = 0.04). Every case had a range that crossed the AJCC8 0.8-mm pT1a/pT1b staging boundary. Ulceration was only identified in two of the 10 cases. For ulceration, kappa agreement score was 0.31 (fair). CONCLUSION This study supports the removal of mitotic count from staging, but shows that its scoring is substantially affected by interobserver variation, suggesting that more prescriptive guidelines might have a beneficial impact on its prognostic value.
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Pseudoxanthoma elasticum presenting without typical skin changes. Clin Exp Dermatol 2020; 45:518-520. [PMID: 32212265 DOI: 10.1111/ced.14177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2019] [Indexed: 01/05/2023]
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Malta (MYH9 Associated Elastin Aggregation) Syndrome: Germline Variants in MYH9 Cause Rare Sweat Duct Proliferations and Irregular Elastin Aggregations. J Invest Dermatol 2019; 139:2238-2241.e6. [PMID: 31125547 DOI: 10.1016/j.jid.2019.03.1151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/08/2019] [Accepted: 03/16/2019] [Indexed: 02/05/2023]
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The DILfrequency study is an adaptive trial to identify optimal IL-2 dosing in patients with type 1 diabetes. JCI Insight 2018; 3:99306. [PMID: 30282826 DOI: 10.1172/jci.insight.99306] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 08/21/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Type 1 diabetes (T1D) results from loss of immune regulation, leading to the development of autoimmunity to pancreatic β cells, involving autoreactive T effector cells (Teffs). Tregs, which prevent autoimmunity, require IL-2 for maintenance of immunosuppressive functions. Using a response-adaptive design, we aimed to determine the optimal regimen of aldesleukin (recombinant human IL-2) to physiologically enhance Tregs while limiting expansion of Teffs. METHODS DILfrequency is a nonrandomized, open-label, response-adaptive study of participants, aged 18-70 years, with T1D. The initial learning phase allocated 12 participants to 6 different predefined regimens. Then, 3 cohorts of 8 participants were sequentially allocated dose frequencies, based on repeated interim analyses of all accumulated trial data. The coprimary endpoints were percentage change in Tregs and Teffs and CD25 (α subunit of the IL-2 receptor) expression by Tregs, from baseline to steady state. RESULTS Thirty-eight participants were enrolled, with thirty-six completing treatment. The optimal regimen to maintain a steady-state increase in Tregs of 30% and CD25 expression of 25% without Teff expansion is 0.26 × 106 IU/m2 (95% CI -0.007 to 0.485) every 3 days. Tregs and CD25 were dose-frequency responsive, Teffs were not. The commonest adverse event was injection site reaction (464 of 694 events). CONCLUSIONS Using a response-adaptive design, aldesleukin treatment can be optimized. Our methodology can generally be employed to immediately access proof of mechanism, thereby leading to more efficient and safe drug development. TRIAL REGISTRATION International Standard Randomised Controlled Trial Number Register, ISRCTN40319192; ClinicalTrials.gov, NCT02265809. FUNDING Sir Jules Thorn Trust, the Swiss National Science Foundation, Wellcome, JDRF, and NIHR Cambridge Biomedical Research Centre.
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Evaluation of universal immunohistochemical screening of sebaceous neoplasms in a service setting. Clin Exp Dermatol 2018; 43:410-415. [PMID: 29333623 DOI: 10.1111/ced.13359] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Muir-Torre syndrome (MTS) is a subtype of Lynch syndrome, which encompasses the combination of sebaceous skin tumours or keratoacanthomas and internal malignancy, due to mutations in DNA mismatch repair genes. Sebaceous neoplasms (SNs) may occur before other malignancies, and may lead to the diagnosis, which allows testing of other family members, cancer surveillance, risk-reducing surgery or prevention therapies. AIM To evaluate the efficacy of universal immunohistochemistry (IHC) screening of SNs in a service setting. METHODS Patients with SNs were ascertained by a regional clinical pathology service over a 3-year period. Results of tumour IHC, clinical genetics notes and germline genetic testing were retrospectively reviewed. RESULTS In total, 62 patients presented with 71 SNs; 9 (15%) of these patients had previously diagnosed MTS. Tumour IHC was performed for 50 of the 53 remaining patients (94%); 26 (52%) had loss of staining of one or more mismatch repair proteins. Fifteen patients were referred to the Clinical Genetics department, and 10 patients underwent germline genetic testing. Two had a new diagnosis of MTS confirmed, with heterozygous pathogenic mutations detected in the MSH2 and PMS2 genes (diagnostic yield 20%). The PMS2 mutation was identified in a 57-year-old woman with a sebaceous adenoma and history of endometrial cancer; to our knowledge, this is the first time a PMS2 mutation has been reported in MTS. CONCLUSIONS Universal IHC screening of SNs is an effective method to identify cases for further genetic evaluation. Rates of referral to clinical genetics were only moderate (58%). Increased awareness of MTS could help improve the rate of onward referral.
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A UK feasibility and validation study of the VE1 monoclonal antibody immunohistochemistry stain for BRAF-V600E mutations in metastatic melanoma. Br J Cancer 2016; 115:223-7. [PMID: 27336602 PMCID: PMC4947692 DOI: 10.1038/bjc.2016.106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 03/08/2016] [Accepted: 03/21/2016] [Indexed: 02/04/2023] Open
Abstract
Background: Determining the BRAF mutation status of patients with advanced metastatic melanoma is essential in order to assess patients' eligibility for targeted BRAF inhibitor therapy. The aim of this study was to validate the utility of immunohistochemistry (IHC) to rapidly obtain the BRAF status in the UK cancer centre setting. Methods: All samples sent for molecular testing for detection of the BRAF mutation over a 26-month period were prospectively tested using the VE1 monoclonal antibody IHC stain. Results: Two-hundred and nineteen samples from 214 patients were identified. All patients were AJCC stage III/IV, except one. There was an overall 95.0% (208/219) concordance rate, with a sensitivity of 94.4% (84/89) and a specificity of 95.4% (124/130) when using genomic assays as the gold standard. Discordance resulted from the inability of the molecular technique to detect the V600E2 mutation and an inability of the IHC staining technique to detect non-V600E mutations. Molecular testing on smaller tumour deposits was also unreliable. Conclusions: IHC staining has good sensitivity and excellent specificity for BRAF V600E mutations. BRAF IHC can be incorporated into a BRAF mutation testing algorithm for UK cancer centres to as a feasible first-line assay and identify a subset of cases that require subsequent genomic testing. It has the additional major advantages of reduced cost and rapid turnaround time.
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Abstract
Subcutaneous fat necrosis (SCFN) of the neonate is a rare panniculitis of early life that occurs in association with gestational diabetes and preeclampsia, as well as perinatal asphyxia, hypothermia, and trauma. A characteristic feature of this condition is its self-limiting and monophasic nature. We report a highly unusual case of delayed SCFN in a male neonate involving an anatomically discrete eruption, reminiscent of erythema nodosum, occurring many weeks after his original eruption had resolved.
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Profound acute limb ischemia affecting all four limbs following cocaine inhalation. J Vasc Surg 2015; 61:504-6. [DOI: 10.1016/j.jvs.2013.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Revised: 09/10/2013] [Accepted: 09/11/2013] [Indexed: 11/29/2022]
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Ectopic sebaceous glands: a rare cause of vaginal swelling. Int J Dermatol 2015; 54:e94-5. [PMID: 25556949 DOI: 10.1111/ijd.12737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Primary and secondary intralymphatic histiocytosis. J Am Acad Dermatol 2014; 70:927-33. [DOI: 10.1016/j.jaad.2013.11.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 11/11/2013] [Accepted: 11/12/2013] [Indexed: 11/28/2022]
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Anetodermic pilomatricoma in a patient with hypermobility syndrome. Clin Exp Dermatol 2013; 39:218-20. [DOI: 10.1111/ced.12215] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2013] [Indexed: 11/29/2022]
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Immunobullous dermatosis associated with Waldenström macroglobulinaemia treated with rituximab. Clin Exp Dermatol 2013; 38:866-9. [PMID: 23782150 DOI: 10.1111/ced.12166] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2013] [Indexed: 11/30/2022]
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Abstract
Sweet's syndrome or acute febrile neutrophilic dermatosis has been associated with underlying infection, malignancy, inflammatory disease and certain medications. The infection agents associated with this include Streptococcus species, Yersinia species, Chlamydia species, Salmonella species and Helicobacter pylori. We report a case of Sweet's syndrome in a 73-year-old woman following a 2 week course of severe gastroenteritis caused by Campylobacter species. Histological examination of skin lesions showed marked inflammatory infiltrate throughout the dermis, composed of neutrophils and histiocytes. The patient was successfully treated with topical and systemic steroids. To date, this is the first case of Sweet's syndrome to be reported linked to Campylobacter species to our knowledge.
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Sweat duct proliferation associated with aggregates of elastic tissue and atrophodermia vermiculata: a simulator of microcystic adnexal carcinoma. Report of two cases†. J Cutan Pathol 2010; 37:1002-9. [DOI: 10.1111/j.1600-0560.2010.01527.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
BACKGROUND Merkel cell carcinoma (MCC) is a rare malignant cutaneous tumour, the incidence of which is increasing. Second malignancies have been reported to occur with high incidence in these patients. OBJECTIVES We report the rate and nature of multiple malignancies in patients with MCC treated over a 10 year period in Addenbrooke's Hospital in Cambridge, United Kingdom, as well as the temporal relationship of these additional malignancies to the diagnosis of MCC. RESULTS The 27 patients had an approximately equal sex incidence with a median age at diagnosis of 79 years. Seventy percent (n=19) of patients had a second primary malignant tumour; and 7 of these patients had two or more tumours in addition to the MCC. Eighteen patients had additional cutaneous malignancies: melanoma, squamous cell carcinoma and basal cell carcinoma, and 8 patients presented non-cutaneous malignancy including colorectal, haematological and breast tumours. Of the 28 additional tumours in our patients, half were diagnosed prior to presentation of MCC, 32% within 6 months of diagnosis, and 18% between 6 months and 3 years after diagnosis. Possible reasons for the high rate of additional tumours in this population are discussed. CONCLUSIONS Our figures reflect a higher incidence of multiple malignancies in those with Merkel cell tumour than has previously been reported. This has important implications for the care and surveillance of these patients.
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Steatocystoma multiplex, oligodontia and partial persistent primary dentition associated with a novel keratin 17 mutation. Br J Dermatol 2009; 161:1396-8. [PMID: 19659471 DOI: 10.1111/j.1365-2133.2009.09383.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Generalized granuloma annulare in a photosensitive distribution resolving with scarring and milia formation. Clin Exp Dermatol 2009; 34:e53-5. [PMID: 19438575 DOI: 10.1111/j.1365-2230.2008.03183.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe an unusual case of generalized granuloma annulare (GA) in a 70-year-old man. This occurred in a photosensitive distribution, responded rapidly to topical and systemic treatment, and resolved leaving residual scarring and milia. To our knowledge, this is the first report of the occurrence of milia formation and scarring in association with GA.
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Hidradenitis suppurativa, Dowling-Degos and multiple epidermal cysts: a new follicular occlusion triad. Clin Exp Dermatol 2004; 29:622-4. [PMID: 15550138 DOI: 10.1111/j.1365-2230.2004.01631.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
This case illustrates the rare association between hidradenitis suppurativa (HS) and Dowling-Degos disease (DDD). Furthermore the association of HS, DDD and multiple epidermal cysts has not to our knowledge been described before, but their coexistence in the same patient is likely to reflect the same follicular anomaly. It is possible that a single underlying defect of follicular proliferation may account for the coexistence of these conditions.
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Abstract
We report the case of a patient with atypical Sweet's syndrome characterized by an annular erythema that showed consumption of elastic fibres by giant cells and histiocytes. Although the lesions were found on sun-exposed sites and the first biopsy demonstrated extensive elastophagocytosis, our patient did not have photodamaged skin clinically. A repeat biopsy 5 weeks later demonstrated an abundant collection of neutrophils supporting the diagnosis of Sweet's syndrome. To our knowledge, an elastolytic granulomatous reaction pattern has not been previously reported in Sweet's syndrome.
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Abstract
Pyoderma gangrenosum (PG) is an idiopathic inflammatory disease of unknown aetiology, frequently associated with an underlying systemic condition such as inflammatory bowel disease or haematological malignancy. Its occurrence tends to parallel exacerbations of the underlying disease. Four clinical variants of PG have been described and these include ulcerative, pustular, bullous and vegetative types. We report two cases of the pustular form, which is an uncommon variant of PG, where the pustules do not progress to form ulcers. Both our patients suffered with inflammatory bowel disease which remained quiescent as the pustular PG developed.
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Abstract
We describe two patients with palmar filiform hyperkeratosis, characterized by multiple thin spiny keratotic projections on the palms. The condition has been associated with an underlying malignancy in some cases. One patient has myelofibrosis, an association not previously described. In addition we describe a further patient with filiform hyperkeratoses of both palms and soles with no associated underlying disorder. In view of the relatively high risk of underlying malignancy occurring in patients with filiform hyperkeratosis, these patients should always be investigated fully.
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Antiepiligrin (laminin 5) cicatricial pemphigoid complicated and exacerbated by herpes simplex virus type 2 infection. Australas J Dermatol 2001; 42:271-4. [PMID: 11903160 DOI: 10.1046/j.1440-0960.2001.00518.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A 50-year-old man with antiepiligrin (laminin 5) cicatricial pemphigoid (AeCP) involving the eyes, mouth and skin required a combination of systemic drug therapies to suppress the ocular disease. Herpes simplex virus type 2 infection of the mouth and pharynx precipitated an acute deterioration, with laryngeal involvement and an increase in oral ulceration. This is an unusual complication of long-term immunosuppression and illustrates some of the difficulties in the management of patients with AeCP. Clinical improvement was obtained with oral antiviral therapy and adjustment of his immunosuppressive regimen.
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Abstract
We report elastosis perforans serpiginosa (EPS) arising in three patients with Ehlers-Danlos syndrome, osteogenesis imperfecta and Down's syndrome. These cases illustrate some of the rare but well-recognized disease associations with EPS. The other causes of EPS are reviewed.
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Abstract
A 55-year-old male cardiac transplant recipient presented with cutaneous nodules on the limbs caused by Alternaria alternata. Oral fluconazole 200 mg daily for 3 weeks was ineffective. Itraconazole 100 mg oral daily was ceased when hyperglycaemia developed. Individual lesions were successfully treated with either curettage and cautery or double freeze-thaw cryotherapy. Alternaria spp. are ubiquitous fungal saprophytes which may cause cutaneous infections particularly in immunocompromised patients.
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Abstract
We describe a 60-year-old patient with verrucous carcinoma of the vulva, which recurred 6 years after simple vulvectomy and radiotherapy. Treatment with acitretin led to significant improvement and ongoing disease control has been achieved with low-dose maintenance therapy of 10 mg acitretin daily.
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Effect of H1-receptor blockade on late cutaneous reactions to antigen: a double-blind, controlled study. J Allergy Clin Immunol 1991; 87:1013-9. [PMID: 1673976 DOI: 10.1016/0091-6749(91)90425-n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This study is of the effect of the blockade of histamine H1 receptors by a long-acting antihistamine on the immediate and late clinical response to antigen (Ag) and on the recruitment of eosinophils in the late-phase cutaneous reaction. Ten adult volunteers with late-phase reactions to the intradermal injection of either Dermatophagoides pteronyssinus or Phleum pratense (timothy) pollen performed a double-blind, crossover study. Each volunteer took astemizole, 10 mg, or identical placebo, daily for 2 weeks. Ag in the concentration that induced a late reaction in the screening visit was injected intradermally at the end of each drug period. The early reaction was measured serially for 30 minutes and the late reaction at 4 and 6 hours. Biopsies of the Ag and control sites were also performed at 6 hours. After a 6-week washout period, subjects then took the opposite medication for 2 weeks and returned for skin testing and biopsy. Skin testing demonstrated that astemizole inhibited the immediate response to both histamine and allergen but had no effect on the late response at 4 hours and at 6 hours. Biopsy specimens revealed no significant effect on eosinophil recruitment at 6 hours. We conclude that histamine H1-receptor blockade has no effect on the late cutaneous reaction to Ag.
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Properties of porcine liver and testicular steroid sulphotransferases: reaction conditions and influence of naturally occurring steroids and steroid sulphates. JOURNAL OF STEROID BIOCHEMISTRY 1983; 19:1103-9. [PMID: 6224977 DOI: 10.1016/0022-4731(83)90403-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Sulphotransferase activity has been assayed in porcine liver and testis cytosol using either 3'-phosphoadenosine-5'-phospho [35S]sulphate (PAPS) or unlabelled PAPS as sulphate donors. In porcine liver the sulphotransferase for DHA was linear for up to 10 min, the optimum pH was 7.7 and optimum temperature, 37 degrees C. The apparent Km value was found to be 91 mumol/l and the activity was inhibited non-competitively by 5 alpha-androst-16-en-3 beta-yl sulphate, with all concentrations used (0.02-25 mumol/l) inhibiting the enzyme to the same extent. Time courses for sulphoconjugation of pregnenolone and 5 alpha-androst-16-en-3 beta-ol were linear for up to at least 10 min or up to only 5 min, respectively. The optimum pH values and temperatures were pH 8.0 and 37 degrees C in each case. The porcine testicular sulphotransferase activity for DHA as substrate was linear with time up to 10 min, the apparent Km for the reaction was 2 mumol/l and apparent Vmax 10 nmol/l/mg/min. 5 alpha-Androst-16-en-3 beta-yl sulphate (11.3-45.2 mumol/l) failed to inhibit the enzyme activity. The time-course for the reaction, when pregnenolone was used as substrate, was also linear up to 10 min at the optimum pH 8.0 but, in contrast to the reaction when DHA was the substrate, had an apparent Km of 20 mumol/l and was inhibited by pregnenolone sulphate, 5 alpha-androst-16-en-3 beta-yl sulphate, DHA and 5 alpha-androst-16-en-3 beta-ol, but not by DHA sulphate. 5 alpha-Androst-16-en-3 beta-yl sulphate inhibited the reaction non-competitively and to the same extent at concentrations over the range 11.3-45.2 mumol/l. These data suggest that DHA and pregnenolone may not be sulphoconjugated by the same sulphotransferase. With 5 alpha-androst-16-en-3 beta-ol as substrate, the time-course for its sulphate formation was linear up to 15 min, and this reaction could explain the quantities of 5 alpha-androst-16-en-3 beta-yl sulphate that are found endogenously in porcine testis. Our results further suggest that these quantities could well inhibit the sulphation of pregnenolone in porcine testis in vivo, and the possibility of control of sulphoconjugation in this tissue is discussed. Having regard to the smaller quantities of 5 alpha-androst-16-en-3 beta-yl sulphate present in porcine liver, our results suggest that the sulphation of DHA there may not be so much affected.
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