Search

The data of hair density and hair diameter in the Asian population, especially in Thais, are limited. We aimed to evaluate hair density and hair diameter of members of the Thai population at different scalp sites and to determine the effect of sex and aging as well as to compare the results with those in groups of other ethnicities. Healthy Thais whose hair examination findings were normal were evaluated. Two hundred and thirty-nine subjects participated in this study, of whom 79 were male and 160 were female. Hair density and hair diameter were analyzed at four different scalp sites using quantitative trichoscopic analysis. The highest hair density in Thais was observed in the vertex area. Hair densities at four different scalp sites were significantly different from one another; only hair density at the vertex site showed no significant difference from that in the occipital area. In contrast, hair diameter did not show any statistically significant differences for the different sites. We observed decreased mean hair density with increasing age and found statistically significant differences between participants in their 20s and those in their 60s, while hair diameter remained consistent. Comparing our results with a previous study in other ethnicities, the hair densities in Asians are generally lower. In conclusion, hair density in the Thai population varies at different scalp sites. Aging is a factor in declining hair density. Asians have a lower hair density compared to Caucasian and African populations., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2020 Kanchana Leerunyakul and Poonkiat Suchonwanit.)

This study was designed to characterize the location, morphology and ultrastructure of telocytes (TCs) in human scalp tissue. After obtaining approval for this study and informed consent from the patient, a scalp specimen was obtained. The distribution and morphology of TCs in human scalp tissue was assessed by immunohistochemical staining of CD34 and CD117/c-KIT, and the ultrastructure of TCs was investigated using transmission electron microscopy (TEM). Immunohistochemical staining of CD34 revealed that TCs were located in the connective tissue of human scalp, and were concentrated around hair follicles (HFs), blood vessels, sweat glands, sebaceous glands and adipose lobules. Immunohistochemical staining of CD117 revealed that TCs were mainly located in the dermis of human scalp, surrounding the HFs and sweat glands. Under TEM, TCs were seen and confirmed by their special morphological features. These cells were spindle-shaped, had small cell bodies and long thin processes, and surrounded stem cell clusters in the bulge region of HFs. These results demonstrate that TCs in human scalp were positive for CD34 and CD117, and their strategic positioning surrounding stem cells suggests their possible involvement in local regeneration, remodeling and homeostasis of the skin.

Tissue expansion has been widely used for plastic, reconstructive, and esthetic surgeries. A mouse scalp expansion model can effectively mimic the characteristics of human skin expansion. However, a detailed study of the histological features and ultrastructural characteristics of expanded scalp is lacking, especially early ultrastructural changes. Here, a mouse scalp expansion model was established and the expanded scalp samples were obtained on day 2 (group I) and 4 (group II) post final injection. Histological analysis revealed epidermal thickening, dermal thinning, subcutaneous fat thinning, and capsule formation in the expanded samples. Ultrastructural evaluation showed the presence of keratinocytes with numerous tonofibrils and damaged mitochondria, and several ruptured collagen fibers and increased number of active fibroblasts and myofibroblasts were observed in the dermis and capsules. Adipocyte dedifferentiation was detected in the expanded samples of both groups, but formation of autophagosomes was only detected in the dermal fibroblasts of group I. Thus, early changes in expanded tissue should be carefully monitored, as it may help avoid dermal thinning and promote expanded tissue regeneration.

Background: Transition of hair shaft keratinocytes from actively respiring, nucleated cells to structural cells devoid of nucleus and cytoplasm is key to hair production. This form of cell 'death', or cornification, requires cellular organelle removal to allow the cytoplasm to become packed with keratin filament bundles that further require cross-linking to create a strong hair fibre. Although these processes are well described in epidermal keratinocytes, there is a lack of understanding of such mechanisms, specifically in the hair follicle., Objectives: To gain insights into cornification mechanisms within the hair follicle and thus improve our understanding of normal hair physiology., Methods: Scalp biopsies and hair-pluck samples were obtained from healthy human donors and analysed microscopically after immunohistochemical staining., Results: A focal point of respiratory activity was evident in keratogenous zone cells within the hair shaft, which also exhibited nuclear damage. Nuclear degradation occurred via both caspase-dependent and caspase-independent pathways. Conversely, mitophagy was driven by Bnip3L and restricted to the boundary of the keratogenous zone at Adamson's Fringe., Conclusions: We propose a model of stepwise living-dead transition within the first 1 mm of hair formation, whereby fully functional, nucleated cells first consolidate required functions by degrading nuclear DNA, yet continue to respire and provide the source of reactive oxygen species required for keratin cross-linking. Finally, as the cells become packed with keratin bundles, Bnip3L expression triggers mitophagy to rid the cells of the last remaining 'living' characteristic, thus completing the march from 'living' to 'dead' within the hair follicle., (© 2017 British Association of Dermatologists.)

Successful use of tissue expanders depends on the quality of expanded tissue. This study evaluates the impact of anisotropic self-inflating tissue expander (SITE) on the biomechanics of skin. Two different SITE were implanted subcutaneously on sheep scalps; SITE that requires 30days for maximum expansion (Group A; n=5), and SITE that requires 21days for maximum expansion (Group B; n=5). Control animals (n=5) were maintained without SITE implantation. Young's Modulus, D-periodicity, overlap and gap region length, diameter, and height difference between overlap and gap regions on collagen fibrils were analyzed using atomic force microscopy. Histology showed no significant differences in dermal thickness between control and expanded skin of groups A and B. Furthermore, most parameters of expanded skin were similar to controls (p>0.05). However, the height difference between overlap and gap regions was significantly smaller in group B compared to both control and group A (p<0.01). Strong correlation was observed between Young's Modulus of overlap and gap regions of the control and group A, but not group B. Results suggest that a relatively slower SITE can be useful in reconstructive surgery to maintain the biomechanical properties of expanded skin., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Cutaneous discoloration secondary to dermal deposition of titanium dioxide (TiO2) particles is recognized but seldom reported in the literature. In this report, the authors describe the case of a 61-year-old gentleman, with a long history of alopecia areata, who presented with numerous, discrete dark blue macules on the scalp. Scanning electron microscopy with energy dispersive x-ray spectroscopy analysis ultimately identified the macules as deposits of TiO2. The patient had a history of intralesional triamcinolone injections for management of alopecia areata. A sample of generic 0.1% triamcinolone acetonide paste was analyzed and found to contain many TiO2 particles analogous to those seen in the patient's biopsy sample. To the authors' knowledge, this is the first reported case of TiO2 deposition in the dermis likely resulting from topical combined with intralesional triamcinolone injection.

Follicular unit transplantation is the most commonly performed technique in modern restorative hair transplantation surgery. It relies on the acquisition of intact follicular units from microdissected scalp skin strips and their subsequent transplantation into the recipient regions affected by alopecia. Ideally, the translocation of follicular units from the balding-resistant areas of the scalp (usually the occipital region) to the recipient site should not result in any morphological change in the grafts. Nevertheless, the insults associated with surgical intervention present grafted follicles to mechanical and chemical cues differently from those of the physiological steady-state conditions in undamaged skin. This disruption of the normal follicular microenvironment might alter important aspects of hair biology in grafts, for example, hair cycle and pigmentation, and, in turn, could lead to differences in hair appearance, eventually culminating in a diminished esthetical outcome of the surgery. In this study, the authors analyzed native and grafted scalp hair follicles (HFs) from 2 patients who had undergone follicular unit transplantation surgeries formerly. Scanning electron microscopy and light microscopy-based histomorphometry revealed a marked enlargement of follicular structures in the grafts with a concomitant increase in hair shaft diameter. Immunohistological staining confirmed a thickening of the dermal sheath in transplanted HFs that also harbored a denser vascular network. Taken together, these results show that the grafted HFs analyzed were subjected to marked morphological changes during their residence in the recipient site and that this phenomenon is associated with a modulation of follicular vascularization.

The content of ATP in scalp hair bulbs in humans was measured in the hair roots from 15 healthy volunteers. Light and electron microscopy confirmed the presence of outer and an inner root sheaths in the root of pulled out anagen hair. Incubation of samples in buffer solution led to extraction of ATP, which was measured by the chemiluminescent method. Mechanic disintegration of hair bulbs and their freezing-defrosting did not increase ATP output. The results of microscopy indicated that ATP extraction procedure was associated with separation of the outer radical sheath from the inner one without impairing the structure of the inner sheath. The mean content of ATP was 12 ± 2 pmol per bulb. The use of pulled out hair bulbs for ATP measurements simplified the procedure as involved no surgical removal of follicles.

Hair and scalp disorders represent a substantial complaint in most dermatologists' daily practice. Trichoscopy is a simple and easy-to-perform technique that has been utilized for diagnosis and management of these patients. The interest for this technique had increased in the last years, and knowledge had expanded. This article reviews the most important dermoscopic patterns in normal Caucasian and African scalp, as well as in the most common trichological conditions.

The changes of the sebaceous gland number, size and sebocyte proliferative activity were studied in the temporal area of the scalp skin in the male individuals aged 10 to 70 years (n=77, autopsy material). The minimal number of the sebaceous glands was observed in children. This index rapidly increased thereafter, reaching a peak at 20 years, then gradually decreased. These parameters correlated with the sebaceous gland size, sebocyte proliferative activity and total blood testosterone level. In older men the size of the sebaceous glands was increased.

Histological, morphometric and immunocytochemical methods were used to study the autopsy samples of the interfollicular epidermis in the temporal region of scalp of male individuals aged from 7 months to 75 years. Monoclonal antibodies against Ki-67, involucrin and p53 were applied to evaluate the proliferative pool in the epidermis, the thickness of the layer of the cells which started the terminal differentiation, and the fraction of the apoptotic cells. Epidermis in children was thin; it had a low content of Ki-67- and p53-positive cells and small thickness of involucrin-positive cell layer. The highest proliferative activity and maximal thickness of the epidermis were detected at the age of 19-21 years. Thereafter the epidermis thinning was observed, together with the progressive decrease of keratinocyte proliferative activity and an increase of the fraction of p53-positive cells. Absolute thickness of the involucrin-positive cellular layer remained practically constant at different ages, while its proportion in the total epidermal thickness uncreased.

A 3-year-old girl showed fine, sparse, and brittle scalp hair without signs of cicatricial cutaneous alterations. Dermoscopy as well as scanning electron microscopy revealed elliptical nodes as well as constricted regions along the hair shaft.

A 29-year-old woman presented with facial edema, and imaging disclosed a tumor extending from the anterior chest wall to the anterosuperior aspect of the mediastinum. Transbronchial cytology of the primary tumor and biopsy of the metastatic scalp lesion were performed. Histologically, the tumor consisted of closely packed small round cells. The neoplastic cells generally had round nuclei, finely dispersed chromatin, and small to prominent nucleoli. Histochemically, the cytoplasm of the neoplastic cells contained abundant glycogen and stained with Grimelius silver. Immunohistochemically, the neoplastic cell membranes reacted with CD99 (MIC2) and the neoplastic nuclei reacted with Fli-1, but various other markers, including lymphocyte and skeletal muscle markers, were not detected. No neoplastic cells were also reactive for chromogranin A, synaptophysin, and neurofilament. Ultrastructurally, some neoplastic cells had delicate cytoplasmic processes and contained membrane-bound dense core granules in the cytoplasm. Even if results are immunohistochemically negative for neuroendocrine markers, the combination of immunohistochemistry of CD99 (MIC2) and Fil-1 may be useful in diagnosing Askin tumor or its metastatic lesion.

A comparative study of AFM and SEM imaging of the same area of a human scalp hair has been carried out to determine the similarity and the differences between the two techniques. Sample preparation for SEM analysis requires a metallization step and vacuum exposure, both of which could potentially induce modifications to the surface details. By contrast, AFM is a suitable technique to evaluate any effect resulting from sample manipulation because it can be applied without any specific treatment. AFM analysis demonstrates that sample metallization is responsible for modifications to the surface details of hair, mainly comprising an increase in height of scale steps and of root mean square roughness together with variation in scale profiles. Sample treatments for SEM imaging are in general potentially responsible for surface modifications to the samples involved.

Background: Mixed tumours are composed of an admixture of an epithelial/myoepithelial and usually a myxochondroid stromal component. Adipocytes are found more rarely, and account for a minor part of the tumour. To date, only three cases of mixed tumour/pleomorphic adenoma of the salivary gland have been described, showing an extensive adipocyte content of more than 90% of the tumour tissue. Owing to this peculiarity, some authors have defined it as 'lipomatous pleomorphic adenoma'. We are not aware of previously reported similar lesions in the skin., Objectives: We report a case of a tumour that occurred as a 2 x 2 x 1.5 cm nodule in the scalp of a 65-year-old man. Analogies with salivary lipomatous pleomorphic adenoma, as well as histogenesis and differential diagnoses are discussed here., Methods: A histological, immunohistochemical and ultrastructural study was performed., Results: The tumour was well-circumscribed and showed a substantial mature adipose tissue component intermingled with epithelial cells arranged in ducts and branching tubules, embedded in a fibromyxoid stroma, which was diagnostic of a chondroid syringoma/mixed tumour. Adipocytes strongly expressed S-100 protein and cytokeratin 14. Transitional elements from epithelial/myoepithelial cells into adipocytes were observed. They coexpressed cytokeratin 14, S-100 protein and vimentin, and showed lipid droplets, desmosome-type junctions, cytoplasmic tonofilaments and basal lamina., Conclusions: The tumour differed from lipomas with myxoid stroma and from lipoadenomas, which show non-proliferating normal sweat glands admixed with adipose tissue. Because of the similarity to lipomatous pleomorphic adenoma/mixed tumour of salivary glands, we suggest that it should be called 'lipomatous mixed tumour of the skin'.

Transmission electron microscopy of scalp tape strips indicates that dandruff scalp possesses abnormal stratum corneum (SC) ultrastructure that is normalized by treatment with small-particle zinc pyrithione (ZPT). Similar abnormalities occur throughout the scalp of those with dandruff, even where no flaking is present. SC abnormalities are consistent with hyperproliferation, including parakeratosis, lipid droplets within corneocytes, few desmosomes, corneocyte membrane interdigitation, and excessive disorganized intercellular lipid. Reversal of SC abnormalities would require treatment of the cause(s) of dandruff, not merely flake removal. A protocol was developed to quantify scalp structural abnormalities by scoring cells from scalp tape strips for yeast number, amount of intercellular lipid, normal intercellular lipid structures, prevalence of intracellular lipid droplets, parakeratotic corneocytes, and corneocyte interdigitation. This protocol was used to compare dandruff and normal SC to dandruff SC treated with either commercial ZPT-containing shampoo or a placebo. Treatment with commercial ZPT shampoo significantly returned SC ultrastructure to normal, suggesting control of the cause of dandruff.

Lipedematous alopecia is a rare condition of unknown etiology characterized by a thick, boggy scalp with varying degrees of hair loss that occurs in adult black females, with no clearly associated medical or physiologic conditions. The fundamental pathologic finding consists of an approximate doubling in scalp thickness resulting from expansion of the subcutaneous fat layer in the absence of adipose tissue hypertrophy or hyperplasia. Observations by light and electron microscopy detailed in this report suggest that this alteration principally manifests by localized edema with disruption and degeneration of adipose tissue. Some diminution in the number of follicles as well as focal bulb atrophy is noted. Aberrant mucin deposition such as that seen in myxedema or other cutaneous mucinoses is not a feature. The histologic findings bear some resemblance to those seen in lipedema of the legs, a relatively common but infrequently diagnosed condition. We present a case of lipedematous alopecia with emphasis on histologic and ultrastructural features. The etiology is unknown.

Cuticle step height is an important parameter for the quantitative assessment of human hair. This paper describes a novel, computational method for the rapid calculation of step heights from atomic force microscope images obtained from large numbers of specimens. Such an approach is necessary to allow a statistical analysis of the inherently wide distribution of cuticle step heights characteristic of a single hair sample. The method described will be of use to cosmetic formulation chemists and forensic scientists and also to dermatologists in the field of disease diagnosis.

Background: The acquired progressive kinking of scalp hair is a disorder in which affected hairs resemble secondary sexual hairs. Some authors have evoked an androgen-related disorder that heralds the onset of androgenetic alopecia. To verify this hypothesis, we focused our attention on a 23-year-old man who has this unusual disorder, which is progressing toward androgenetic alopecia. Patient's circulating 5 alpha-reductase reduced androgen levels; scalp skin 5 alpha-dihydrotestosterone formation; and trichography, histological, scanning, and polarizing electron microscopy analyses were compared in normal and affected scalp skin areas., Observations: Results of histological and scalp skin 5 alpha-dihydrotestosterone formation analyses and comparison of growth pattern of kinky hair in the affected areas with that of healthy hair were similar to those found in androgenetic alopecia., Conclusions: No data are available to confirm the presence of a sole entity, even if our arguments support our hypothesis. The confirmation of this tendency warrants further investigation.

Alopecia areata is a form of balding whose aetiology is uncertain. Although the dermal papilla in the hair bulb regulates the follicle and may play a part in the pathogenesis of alopecia areata, its ultrastructure has not been well described. As clinically normal, i.e. non-balding, follicles from alopecia areata scalps show abnormalities at the light microscope level, it would be expected that they should exhibit the earliest pathological changes involved in the dysfunction of the follicle. This study was designed to investigate the ultrastructure of normal human scalp follicular dermal papillae and to see if changes occurred in the ultrastructure of dermal papillae from either lesional or non-balding regions of alopecia areata. Normal dermal papillae contained well formed fibroblast-like cells with large, oval nuclei and well-developed endoplasmic reticulum; the cells were separated from each other by extracellular matrix containing small pieces of collagen and basal lamina-like material. Dermal papillae from both clinically normal and lesional alopecia areata follicles were less well organized and the dermal papilla cells exhibited signs of cell injury and contained abnormal amounts of pigment; an increased concentration of fibrous material in the extracellular matrix and thickening of the dermal papilla-epithelial junction were also seen. Follicles from lesional areas showed more pronounced changes than clinically normal ones. Ultrastructural abnormalities in the dermal papillae of clinically normal scalp follicles support the study of these follicles as a prime research target. The changes detected suggest that dermal papilla cells in alopecia areata would be less able to synthesize regulatory factors and that these may have more difficulty crossing into the epithelial compartment. They are consistent with an early pathological role for the dermal papilla in alopecia areata, but do not distinguish whether this is a primary aetiological role or a secondary response to an insult elsewhere in the follicle.

Terminal hair follicles extracted after ethylenediaminetetraacetic acid treatment preserved the basal cell surface of the outer root sheath well enough to examine the outer surface in detail. Light microscopic observations of whole mount specimens revealed several sawtooth-like structures of follicular epithelium in the lower portion of terminal hair follicle. Vertical sections of the human scalp also showed several invaginations of the outer root sheath of terminal hair follicles in the lower portion, not in association with the arrector pili muscle. Scanning electron microscopy of the same specimens demonstrated accordion-like structures below the sebaceous gland in the lower half of anagen terminal hair follicles and surrounding the entire circumference of the follicles. Sawtooth-like structures were unilaterally observed at the level of the middle or lower portion below the sebaceous gland. With transmission electron microscopy, these structures were seen as undulations of basal cells which preserved hemidesmosomes, although the basal lamina had been peeled off during the extraction procedure. Thus, this accordion-like structure is a genuine structural variation of some human anagen hair follicles and not an artifact.

Eosinophillic panniculitis is a poorly defined entity with variable clinical features. We report a case of rapidly enlarging, asymptomatic subcutaneous scalp nodules in a 6-year-old black boy with atopic dermatitis. The nodules resolved spontaneously over two to three days. Biopsy specimens were remarkable for eosinophilic panniculitis without evidence of epidermal change or vasculitis. We believe that this is the youngest reported patient with this disorder.

Scanning electron microscopic studies of human terminal hair follicles of the scalp and eyebrow have previously been limited to the hair shaft. In this study we investigated EDTA-treated extracted whole hair follicles in which most of the basal cell surface of the outer root sheath was well preserved. In the bulge area of scalp follicles there were many knob-like or villous projections. These were located in some specimens on one side of the follicle, while in others they were located around the entire circumference of the follicle. These projections were thought to represent the anchoring points of the branched follicular end of the arrector muscles. Ring-like elevations with groove-like depressions above and below were also observed surrounding the entire follicle. These were thought to represent the track of circumfollicular arrector muscles which depressed the outer root sheath when they repeatedly contracted. Most anagen eyebrow follicles showed morphological variations in the bulge area such as lattice-window-like structures and undulation patterns. In telogen follicles, the bulge became indistinguishable from the clubbed end. The lower end of these telogen follicles showed irregularly shaped bulge areas, but did not show lattice-window-like structures or undulation patterns as observed in anagen follicles. Interestingly, a hole was found in some bulge areas of both anagen and telogen follicles. Serial vertical sections of follicles revealed invaginated areas, which seemed to correspond to the openings seen in whole mounts. In vertical sections of eyebrow follicles some keratinocytes of the outer root sheaths of the bulge area were seen to be melanized to various extents. This phenomen was independent of hair cycle phase.

The purpose of this study was to identify the distribution of androgen receptors in the bald and hairy scalp of adult male and female stumptail macaque monkeys by light microscopic biotin-avidin immunocytochemistry with a highly purified rat monoclonal antibody against the cloned human androgen receptor. Consistent, intense nuclear and minimal cytoplasmic immunostaining was observed in several distinct cell populations of the pilosebaceous unit including the dermal papilla, hair epithelium, outer root sheath, dermal sheath, and sebaceous gland. A similar distribution of androgen receptors was found in miniaturized and terminal anagen and telogen follicles of the bald and hairy scalp, respectively. Binding of androgen receptor antibody was also detected in dermal fibroblasts, basal and intermediate layers of the interfollicular epidermis, and duct and glandular cells of eccrine sweat glands. This investigation demonstrates the presence of androgen receptors in the pilosebaceous unit of the scalp of the stumptail macaque and also shows that their distribution is comparable to that previously reported for humans.

A nodule from the scalp of a 14-year-old boy was diagnosed by light and electron microscopy as a meningioma. There was no evidence of an intracranial lesion or involvement of the bone of the skull. The tumor was excised but recurred and metastasized to lung and chest wall.

The scanning electron microscope has been used to examine scales taken from the scalp of 3 patients with pityriasis amiantacea alone, 3 psoriatic patients with pityriasis amiantacea and one patient with both atopic dermatitis and pityriasis amiantacea. Samples from 2 patients were additionally studied by different fixation techniques and in the frozen hydrated state, but no cementing of the scales could be observed. There was no evidence of an infective agent.

The purpose of these experiments was to determine if an extracellular calcium binding site gradient is evident in freshly dissected or cultured mouse vibrissa and human scalp follicles and to measure possible drug effects on this gradient. Mouse vibrissae were cultured with or without either minoxidil or pinacidil, and human scalp follicles were cultured with or without epidermal growth factor. Anagen vibrissa and scalp follicles were dissected and placed in culture for 4 h to 4 days, then fixed in a solution containing lanthanum chloride and prepared for either quantitative energy-dispersive X-ray microanalysis (X-ray) or qualitative transmission electron microscopy (TEM). Since lanthanum has a high charge density it displaces Ca2+ ions from anionic binding sites. TEM analysis revealed extensive accumulation of electron-dense lanthanum deposits in the intercellular compartment of differentiating cells in the hair shaft and inner root sheath in the apex of the follicular bulb. Sparse lanthanum precipitate was observed in the intercellular space of the proliferative cells at the base of the bulb. This gradient of lanthanum precipitate was evident in both freshly dissected and cultured vibrissa and scalp hair follicles, irrespective of treatment with drugs that grow hair or epidermal growth factor. X-ray microanalysis indicated that percent by weight of lanthanum was markedly higher in the apex compared to the base of the follicular bulb in vibrissa and scalp follicles. These qualitative and quantitative data demonstrate that an extracellular calcium binding site gradient exists in cultured vibrissa and scalp hair follicles, and that this gradient is not significantly affected by hair growth altering drugs including minoxidil or pinacidil, and epidermal growth factor.

Hair-bearing, transitional, and alopecic scalp from three males and one female with progressive pattern alopecia were examined. Ultrastructural studies disclosed measurable thickening of the follicular adventitial sheaths of transitional and alopecic zones compared with those in the non-alopecic zones. This finding was associated with mast cell degranulation and fibroblast activation within the fibrous sheaths. Immunohistochemically, control biopsies were devoid of follicular inflammation (n = 3), while transitional regions consistently showed the presence of activated T-cell infiltrates about the lower portions of follicular infundibula. These infiltrates were associated with the induction of class II antigens on the endothelial linings of venules within follicular adventitia and with apparent hyperplasia of follicular dendritic cells displaying the CD1 epitope. Inflammatory cells infiltrated the region of the follicular bulge, the putative source of stem cells in cycling follicles. The data suggest that progressive fibrosis of the perifollicular sheath occurs in lesions of pattern alopecia, and may begin with T-cell infiltration of follicular stem cell epithelium. Injury to follicular stem cell epithelium and/or thickening of adventitial sheaths may impair normal pilar cycling and result in hair loss.

Keratosis follicularis spinulosa decalvans (KFSD) is a genetic disorder characterized by disseminated follicular hyperkeratosis, especially localizated to scalp and face. We report the case of a new patient displaying typical features of KFSD. Ultrastructural study was performed and displayed round keratohyalin granules in follicular keratinocytes. Trial with etretinate, which has not been reported before in this disease, proved to be ineffective.

An adnexal tumor on the scalp of a 74-year-old woman is described. Histologically, the tumor was composed of cystic structures showing typical trichilemmal keratinization. The tumor cells in the cyst walls often formed duct-like or squamous eddy-like structures and occasionally showed vacuolation or poroma-like change. Ultrastructurally, some tumor cells showed differentiation either toward the acrosyringium or sebaceous cells. From these findings, the present tumor is considered to differentiate toward various parts of the hair follicle including infundibulo-isthmus epithelium, apocrine acrosyringium, and sebaceous cells.

A case of cutaneous metastasis of renal cell carcinoma in a 67-year-old man is described. Right side nephrectomy had been performed three years earlier, and a renal cell carcinoma was diagnosed. Following a bruise, the patient noticed an erythematous nodule on the scalp. Histological examination of this skin lesion showed atypical tumor cells consisting predominantly of clear cells with a honeycomb-like or adenoid structure. Electron microscopic examination revealed that the tumor cells were divided into three groups: clear cells with abundant glycogen, dark cells with abundant mitochondria, and intermediate cells containing both glycogen and mitochondria in varying proportions. Some of the tumor cells with an adenoid pattern had a brush border-like structure in the lumen. These results support the diagnosis of metastatic renal cell carcinoma. An electron microscopic approach may aid in diagnosis of cutaneous metastasis from renal cell carcinoma.

The dermal papilla is believed to exert controlling influences on hair growth. This report documents, for the first time, the occurrence of intranuclear rodlets in normal cultured human dermal papilla cells. Intranuclear rodlets have been observed predominantly in normal neurons, neural neoplasms, and paraneuromas. Whereas intranuclear rodlets and complex intranuclear bodies have not been identified in dermal papilla cells in vivo, they were observed, by light microscopy and transmission electron microscopy, in primary and subsequent passaged cultures in all 10 individuals examined. Intranuclear rodlets and bodies were not found, however, in parallel cultures of scalp dermal fibroblasts from the same individuals. Rodlet ultrastructure in cultured dermal papilla cells exhibited many features in common with previous reports on rodlets in neuronal and paraneuronal cells. Features that differentiated the rodlets in this study, however, included: doublet/triplet rodlets in the same nucleus; rodlets or crystalline filament bundles within complex nuclear inclusions; close relationship with the nuclear membrane, and their frequent intimate association with intranuclear bodies; and nucleoli and fine chromatin-distinct fibrillar material. Although the function of these true intranuclear inclusions in dermal papilla cells is unknown, it is noteworthy that they were present in these highly metabolically active fibroblasts while absent in comparatively less active dermal fibroblasts, and may indeed be a marker for this fibroblast cell type.

The involvement of proteoglycans in hair growth has been recognized through the observation of increased hair growth in diseases such as the mucopolysaccharidoses and pre-tibial myxedema, which involve an increase in skin proteoglycan content. In an attempt to understand this, we have examined the distribution of chondroitin 6 sulphate (C6S), unsulphated chondroitin (COS), dermatan sulphate (DS), and heparan sulphate proteoglycans (HSPG) in frozen tissue sections of normal scalp by immunostaining. Results show that during anagen, the thick connective tissue sheath around the follicle strains strongly for C6S, COS, and DS. COS is uniquely associated with this region and is not found beneath the epidermis or infundibular epithelium. HSPG is, however, localized in the basement membrane zone adjacent to the outer root sheath. In addition, all of these proteoglycans are localized in the dermal papilla. In mid-catagen, we observed significant loss of C6S and COS staining from both the dermal papilla and the connective tissue sheath, but no decrease in staining for HSPG. In late catagen, very little staining of C6S and COS was observed. In early anagen, we observed that C6S was again present in the connective tissue sheath and dermal papilla; however, COS staining appeared to be weaker and less closely associated with the follicle. HSPG staining was observed in early anagen in a pattern very similar to that found for other basement membrane components. Results for DS were not obtained for catagen or early anagen. These results provide further evidence that hair growth is associated with the presence of chondroitin proteoglycans in the follicle environment and that the cessation of growth is associated with their removal. Further studies are underway to characterize the relationship between hair growth and proteoglycans.

We report on a family with the Rapp-Hodgkin ectodermal dysplasia syndrome. Four affected family members are described and a review of the literature is given.

Two patients had localized multiple cutaneous neurofibromas; one had bilateral involvement of the scalp and the other had true segmental neurofibromatosis. Other signs of neurofibromatosis were absent. Segmental neurofibromatosis may not be related to the generalized types of neurofibromatosis but may be a cutaneous hamartoma.

Five cases of a distinctive benign soft tissue lesion of the scalp in patients ranging from 4 months to 40 years of age are described. Clinically, the lesions appeared as solitary, subcutaneous nodules suggestive of a cystic vascular malformation or other benign condition. Histologically, however, the lesions were characterized by a monotonous, pseudoinfiltrative proliferation of cuboidal epithelioid cells arranged in clusters within the dermis and subcutaneous tissue in intimate association with vessels, adipose tissue, and other connective tissue elements. A prominent feature in all cases was the presence of areas simulating freely anastomosing vascular channels lined by round to spindle-shaped, slightly hyperchromatic epithelioid cells reminiscent of angiosarcoma. Immunohistochemically, these cells were negative for factor VIII-related antigen and Ulex europaeus lectin but were strongly positive with vimentin and epithelial membrane antigen antibodies, this latter being in keeping with the immunohistochemical profile of meningothelial cells. The meningothelial nature of these cells was supported by the electron microscopic demonstration in one case of cells with complex, interdigitating cytoplasmic processes that were joined by scattered cell junctions and contained abundant intracytoplasmic intermediate filaments. The intimate admixture of meningothelial elements with haphazardly arranged connective tissue elements sets these lesions apart from cutaneous meningiomas and warrants their designation as hamartomas with an ectopic meningothelial component.

Three cases of malignant hemangioendotheliomas in elderly individuals are recounted. All of them died shortly after onset of the malignancies in spite of radical surgery in one; radical surgery, chemotherapy, and radiotherapy in another; and chemotherapy and radiotherapy in the third. Findings from studies of specimens of the malignancies by conventional microscopy, histochemistry, and electron microscopy are described.

A case of an epitheloid hemangioendothelioma of the skin and subcutaneous tissue of the scalp is described. Clinically and histologically a (metastatic) carcinoma had been considered in differential diagnosis. Of great help in recognition of the endothelial nature of this tumor was the immunohistochemical reaction with Factor-VIII associated antigen and Ulex europaeus antigen. Not only tumor cells in solid areas, but also intracytoplasmic vacuoles revealed positive staining. Thereby it could be shown, that this paranuclear vacuoles are actually compatible with developing capillary lumina. Only few tumor cells showed positive reaction with alpha-1-antichymotrypsin, pointing to a possible small histiocytic component of this tumor. Endothelial features of tumor cells and developing capillary lumina also could be demonstrated by electronmicroscopy.

The third recurrence of a primary mucinous adenocarcinoma of the right parietal scalp was studied by histochemistry and electron microscopy. Histochemically the mucin produced by this neoplasm was of the sialomucine type. Electron microscopy revealed a high differentiated tumour whose cells looked like eccrine mucinous ones. The natural history of this carcinoma is similar to that of 33 ones already published. The tumours, round and elevated, grow in 75 p. 100 of the cases in patients over 50 years of age. They are located on the face or the scalp and more rarely on the trunk. Such tumours are frequently misdiagnosed as carcinomas. But the knowledge of thier morphological and histochemical features should lead to the right diagnosis all the more since the various biological and radiological investigations do not discover other primary neoplasm. Besides if these neoplasms are not metastases they are quite different from the other sweat gland carcinomas. They have a better prognosis than these tumours. However they give local recurrences, lymph node or subcutaneous metastases and a fatal issue in 6 p. 100 of the cases.