Alopecia areata incognita in Cronkhite-Canada syndrome.

Cronkhite-Canada syndrome is an acquired inflammatory polyposis syndrome in which alopecia, onychomadesis and hyperpigmentation occur concurrently with gastrointestinal symptoms. The pathophysiology of alopecia in Cronkhite-Canada syndrome has not been definitively elucidated. We present evidence for alopecia areata incognita as a possible mechanism of hair loss.

Catamenial dermatoses: has anyone ever considered prostaglandins?

Catamenial dermatoses are unusual, cyclic, perimenstrual reactions to hormones produced during the menstrual cycle. They occur in a variety of clinical presentations, including urticaria, eczema, fixed drug eruptions, erythema multiforme and anaphylaxis. Autoimmune progesterone dermatitis is the most common, and is caused by an autoimmune response to endogenous progesterone in women of reproductive age. We report a case of catamenial dermatosis in a 42-year-old Jamaican woman with a 10-year history of cyclic blistering and ulcerative eruptions of her mouth and limbs. Her symptoms were fully in keeping with a Stevens-Johnson-type reaction, and were associated with production of prostaglandins occurring during her menstrual cycle.

Panniculitis with vasculitis.

Panniculitides encompass a great number of different entities; however, once a vasculitis has been detected histopathologically within the subcutaneous tissue, the differential diagnosis is mainly restricted to polyarteritis (panarteritis) nodosa (PAN), nodular vasculitis (NV), and Bazin's erythema induratum (EI). Patients with PAN may have the disease confined to the skin, but must be followed over a long period because many of them develop late systemic disease. The NV/EI group represents by far the most common type of lobular panniculitis with vasculitis; we prefer keeping the distinction between the two entities by underlining the equation NV positive tuberculin skin test = EI. Other lobular panniculitides with vasculitis are exceedingly rare and set in a systemic background which can be infectious (lepromatous leprosy panniculitides) or autoimmune/dysreactive (neutrophilic lobular panniculitis in rheumatoid arthritis, lobular panniculitis in inflammatory bowel disease).

Bullous pemphigoid in a patient with suspected non-Herlitz junctional epidermolysis bullosa.

A 56-year-old man with lifelong trauma-induced blisters, nail dystrophy and dental enamel hypoplasia presented with a new spontaneous blistering eruption. Clinicopathologically, he had evidence of both an inherited and an acquired blistering disorder: non-Herlitz junctional epidermolysis bullosa (nHJEB) and bullous pemphigoid (BP). HIstological examination of a skin biopsy found reduced (but not absent) collagen XVII in nonlesional skin, in vivo bound anticollagen XVII antibodies in perilesional skin, and prominent eosinophils in perilesional and lesional skin, with subepidermal blistering. Circulating anticollagen XVII antibodies were also present. Treatment with oral corticosteroids and mycophenolate mofetil led to clinical control of the BP but had no effect on the mechanobullous blistering. Our patient is unusual in that his skin retains some labelling for collagen XVII rather than having the complete absence of immunoreactivity expected in patients with generalized nHJEB. Moreover, we were unable to identify any pathogenic mutations in the COL17A1 gene encoding collagen XVII (or in other EB-associated basement membrane genes). It is plausible that the long-term consequences of basement membrane disruption in our patient, perhaps associated with atypical inherited COL17A1 pathology, might result in a conformationally altered and more immunogenic protein with the subsequent development of anticollagen XVII antibodies and BP as a secondary pathology.

Localized bullous pemphigoid in a patient with primary lymphoedema tarda.

We report a case of localized bullous pemphigoid (BP) in a woman patient with primary lymphoedema tarda. There is only one previous case reported of localized pemphigoid in an area of lymphoedema, this being of the cicatricial variant. Slow circulation in the lymphatic vessels, increased capillary permeability with preferential localization of antibodies in the area, and potential cleavage of the epidermal junction due to increased hydrostatic pressure leading to autoimmunity, have all been advocated as possible pathogenic mechanisms. Nevertheless, we consider that the mechanism by which localized pemphigoid arises on lymphoedema remains elusive, based on a previous case of generalized BP sparing an area of postsurgical lymphoedema.

Immunohistochemical detection of V600E BRAF mutation is a useful primary screening tool for malignant melanoma.

BACKGROUND: We compared the use of an immunohistochemical (IHC) method using a monoclonal antibody to BRAF V600E (which detects the main BRAF mutation) with existing DNA probe screening in tissue samples from 71 patients with malignant melanoma. MATERIALS AND METHODS: Paraffin blocks were cut to provide consecutive slides for haematoxylin and eosin staining, and for known positive micro-array DNA control material. IHC was performed by the Optiview detection system. All slides were scored independently by the clinical lead and the laboratory lead using a positive/negative system. RESULTS: The DNA method found 26 samples to be positive, the IHC found 21 to be positive, giving a sensitivity value for IHC of 80.8%. However, all of the 45 samples found to be negative by DNA were also negative by IHC, giving a specificity of 100%. There were 66 instances of full agreement, giving a concordance of 93%. Together, these data give a kappa statistic of 0.843, indicating very good agreement. CONCLUSION: The data reveal a very close link between the two methods, supporting the use of the V600E as a primary screen for BRAF mutations in malignant melanoma. Samples found to be negative by this method may be retested by the DNA probe method. IHC detection conserves patient DNA from tumour blocks as only one section is required to perform the assay. The V600E antibody method is considerably cheaper and faster than the DNA probe assay, with a turn-around time of 24-48 hours, enabling more rapid clinical management.