Multiple apocrine hidrocystomas successfully treated with botulinum toxin A.

Apocrine hidrocystomas, while rare, present predominantly as solitary papules occurring in the periocular region of the face. Various treatment modalities for these lesions exist depending on their size and location, but the management of multiple hidrocystomas can be more challenging. Recent reports illustrate that multiple eccrine hidrocystomas have been successfully treated with botulinum toxin A. Herein we describe the effective use of botulinum toxin A in a 29-year-old man with multiple facial apocrine hidrocystomas, which, to our knowledge, has not yet been reported in the English-language literature.

Stem cells in the skin and their role in oncogenesis.

Stem cells generate great interest because they hold the promise for treatment of various incurable diseases. Several distinct stem cell populations have been identified in each organ, including the skin. As the skin is the largest organ in the body and is easily accessible, cutaneous stem cells have raised significant hopes for being a rich source of easily available multipotent stem cells. Genetic alterations and mutations in stem cells are being proposed as initiation step in multiple cancers. Small populations of oncogenic stem cells termed as cancer stem cells or tumour-initiating cells have been identified in multiple tumours, including squamous cell carcinomas, and melanomas that can sustain tumour growth, underlie its malignant behaviour and initiate distant metastases. These cells are controlled and regulated by the same pathways that are also responsible for maintenance and differentiation of normal stem cells. Developing a targeted therapy against the oncogenic stem cells and dysregulated members of the signalling pathways may be the key to understanding and treating skin cancers like melanomas, for which we still do not have an effective treatment.

CT features of plexiform neurofibroma of the submandibular gland.

Plexiform neurofibroma of the submandibular gland is an extremely rare tumor. We report the CT findings in a 6-year-old girl with type 1 neurofibromatosis who had a histopathologically proven submandibular gland plexiform neurofibroma. A "branching" hypodense mass was noted on the CT scan infiltrating the submandibular gland and the adjacent spaces of the neck. CT could be extremely valuable in suggesting the diagnosis.

The evolution of phylogenetic differences in the efficiency of digestion in ruminants.

This study investigates, for the first time (to our knowledge) for any animal group, the evolution of phylogenetic differences in fibre digestibility across a wide range of feeds that differ in potential fibre digestibility (fibre to lignin ratio) in ruminants. Data, collated from the literature, were analysed using a linear mixed model that allows for different sources of random variability, covariates and fixed effects, as well as controlling for phylogenetic relatedness. This approach overcomes the problem of defining boundaries to separate different ruminant feeding styles (browsers, mixed feeders and grazers) by using two covariates that describe the browser-grazer continuum (proportion of grass and proportion of browse in the natural diet of a species). The results indicate that closely related species are more likely to have similar values of fibre digestibility than species that are more distant in the phylogenetic tree. Body mass did not have any significant effect on fibre digestibility. Fibre digestibility is estimated to increase with the proportion of grass and to decrease with the proportion of browse in the natural diet that characterizes the species. We applied an evolutionary model to infer rates of evolution and ancestral states of fibre digestibility; the model indicates that the rate of evolution of fibre digestibility accelerated across time. We suggest that this could be caused by a combination of increasing competition among ruminant species and adaptation to diets rich in fibre, both related to climatically driven environmental changes in the past few million years.

Multiple basaloid follicular hamartomas associated with acrochordons, seborrhoeic keratoses and chondrosarcoma.

Basaloid follicular hamartoma is an uncommon neoplasm with distinctive histopathological findings. It presents as four distinctive clinical forms: a solitary papule, a localized plaque of alopecia, a localized linear and unilateral type, and generalized papules with associated alopecia and myasthenia gravis. Histologically, basaloid follicular hamartomas are characterized by thin branching strands and thick cords of basaloid or squamoid cells extending from a follicle into a loose, fibrillar, fibrocytic or mucinous connective tissue stroma. We report a case of long-standing, generalized basaloid follicular hamartomas associated with acrochordons, seborrhoeic keratoses, and a history of chondrosarcoma. In general, solitary tumours are sporadic; multiple tumours are inherited and frequently associated with a syndrome. Further surveillance is warranted to determine if the association of multiple basaloid follicular hamartomas and chondrosarcoma constitutes an inherited syndrome.

Plantar fibromatosis: use of magnetic resonance imaging in diagnosis.

For patients presenting with classic features of plantar fibromatosis, a presumptive diagnosis may be made on clinical grounds alone. In less clear cases, a biopsy may allow confirmation of the diagnosis; however, a biopsy exposes the patient to operative complications. Magnetic resonance imaging (MRI) offers a noninvasive method for confirmation of the clinical diagnosis that may obviate the need for a biopsy. We describe a case that demonstrates the potential of this technique.

Fluorescence of fungi in superficial and deep fungal infections.

BACKGROUND: Fluorescence of many fungi is noted when H&E stained sections are examined under a fluorescent microscope. In theory, this phenomenon could aid in the diagnosis of cutaneous and disseminated fungal infections without the delay associated with special stains. Seventy-six cases of superficial and deep fungal infections and 3 cases of protothecosis were studied to determine the clinical usefulness of this technique. RESULTS: In most cases, fluorescence was noted, but was not intense. Fluorescence of fungi did not correlate with the age of the specimen. In most cases, organisms in H&E stained sections were more easily identified with routine light microscopy than with fluorescent microscopy. CONCLUSION: This report suggests that in H&E stained skin specimens, fluorescent microscopy is of little benefit in the identification of fungal organisms.

Solitary nodule of the great toe.

We describe a 21-year-old woman with a subungual exostosis exhibiting both skin and nail findings. The patient presented with a firm, flesh-colored, nontender, subungual nodule in the distal nail bed of the great toe. Radiographic examination revealed focal calcification of the nodule, with direct communication to the underlying phalanx. Subungual exostosis should be considered in the differential diagnosis of any digital mass. Surgical excision, followed by curettage of the base, is the treatment of choice.

Analysis of aggregation, a worked example: numbers of ticks on red grouse chicks.

The statistical aggregation of parasites among hosts is often described empirically by the negative binomial (Poisson-gamma) distribution. Alternatively, the Poisson-lognormal model can be used. This has the advantage that it can be fitted as a generalized linear mixed model, thereby quantifying the sources of aggregation in terms of both fixed and random effects. We give a worked example, assigning aggregation in the distribution of sheep ticks Ixodes ricinus on red grouse Lagopus lagopus scoticus chicks to temporal (year), spatial (altitude and location), brood and individual effects. Apparent aggregation among random individuals in random broods fell 8-fold when spatial and temporal effects had been accounted for.