A clinical and biological review of keratoacanthoma.

Keratoacanthoma (KA) is a common skin tumour that remains controversial regarding classification, epidemiology, diagnosis, prognosis and management. Classically, a KA manifests as a rapidly growing, well-differentiated, squamoid lesion with a predilection for sun-exposed sites in elderly people and a tendency to spontaneously regress. Historically, KAs have been considered a variant of cutaneous squamous cell carcinoma (cSCC) and are often reported as KA-type cSCC. However, the penchant for regression has led many to categorize KAs as biologically benign tumours with distinct pathophysiological mechanisms from malignant cSCC. The clinical and histopathological similarities between KA and cSCC, particularly the well-differentiated variant of cSCC, have made definitive differentiation difficult or impossible in many cases. The ambiguity between entities has led to the general recommendation for surgical excision of KAs to ensure a potentially malignant cSCC is not left untreated. This current standard creates unnecessary surgical morbidity and financial strain for patients, especially the at-risk elderly population. There have been no reports of death from a definitive KA to date, while cSCC has an approximate mortality rate of 1·5%. Reliably distinguishing cSCC from KA would shift management strategies for KAs towards less-invasive treatment modalities, prevent unnecessary surgical morbidity, and likely reduce associated healthcare costs. Herein, we review the pathophysiology and clinical characteristics of KA, and conclude on the balance of current evidence that KA is a benign lesion and distinct from cSCC.

Minocycline-induced hyperpigmentation in patients with pemphigus and pemphigoid.

BACKGROUND: Immunosuppressive medications typically used to treat the immunobullous disorders pemphigus vulgaris, pemphigus foliaceous, and bullous pemphigoid can have serious adverse effects. The tetracycline family of antibiotic drugs has been shown to be effective in the treatment of these conditions with a more favorable side effect profile. Minocycline hydrochloride use has been associated with various forms of hyperpigmentation, and its incidence is well reported in acne vulgaris and rheumatoid arthritis. We examined a series of 9 patients treated with minocycline for pemphigus or pemphigoid, most of whom have developed cutaneous hyperpigmentation. OBSERVATIONS: Seven of 9 patients treated with minocycline, 50 mg daily (1 patient) or 100 mg twice daily (8 patients), for pemphigus vulgaris, pemphigus foliaceous, or bullous pemphigoid developed hyperpigmentation, which necessitated discontinuing therapy. Five of these patients had experienced notable clinical improvement of their immunobullous disease with minocycline therapy. The average duration of treatment was 8.2 months (range, 1-25 months). The second most common adverse effect in our group was oral candidiasis, which occurred in 2 patients. CONCLUSIONS: We found a favorable response to minocycline therapy in 5 of 9 patients. However, 7 patients developed localized hyperpigmentation as early as 1 month after starting medication use. This incidence of minocycline-induced hyperpigmentation is significantly higher in immunobullous disease than in acne vulgaris or rheumatoid arthritis. This increased incidence may be related to an increase in pigment deposition complexed with collagen during the remodeling process, subclinical inflammation, or glucocorticosteroid-induced skin fragility. The hyperpigmentation process was reversible, as most of our patients had fading of their pigmentation after minocycline cessation.

An exaggerated response to beta-adrenergics.

Beta-adrenergics are used frequently in the management of asthma. Tremor has been found to be a limiting side effect with the oral or the inhaled forms. We describe one child who developed gross tremors necessitating an extensive neurologic evaluation to eliminate any other cause. With the results of a normal work-up and the reappearance of tremor when challenged again, the diagnosis of increased sensitivity to the tremorogenic effect of beta-adrenergics was made.

Congenital erythropoietic porphyria associated with myelodysplasia presenting in a 72-year-old man: report of a case and review of the literature.

Congenital erythropoietic porphyria (CEP) is a rare autosomal recessive disease owing to the deficient activity of uroporphyrinogen III synthase, the fourth enzyme in the porphyrin-haem synthetic pathway. Of the porphyrias, it is the most mutilating type, usually presenting early in life. To date, 12 documented cases of adult onset CEP have been reported. We report the second oldest documented patient with late onset CEP with incidental findings of thrombocytopenia and myelodysplasia with bone-marrow sideroblasts. We further discuss several current and future treatment options for this therapeutically challenging disease.