HMB 45 positive balloon cells in combined nevi]

The combined naevus is made up of two components, one resembling a melanocytic naevus, the other a blue naevus. Clinically, these naevi do not give any obvious cause for concern. Histological examination shows that the combined naevus consists of a superficial melanocytic naevus and a deep-seated spindle cell blue naevus. There is a rare variant in which the pigmented spindle cells of the "blue" naevus are replaced by large balloon cells varying in melanin content. These combined naevi, because of the large cells with abundant cytoplasm, closely resemble malignant melanoma. As a further aid to diagnosis we used the monoclonal antibody HMB 45. In our study, the vesicular cells in all seven combined naevi examined reacted strongly with HMB 45. It is suggested that HMB 45 is not always helpful in differentiating between melanoma and naevi.     

The cutaneous pathology of extrafacial lesions in Cowden's disease

Twenty extrafacial lesions from 6 patients with Cowden's disease were studied. Most were hyperkeratotic papillomas that resembled verruca vulgaris, acrokeratosis verruciformis , or hyperkeratotic acanthomas. Small hyperkeratotic papillomas frequently showed abnormalities of the follicular infundibulum. Occasionally, follicular abnormalities were seen without concomitant epidermal hyperplasia. It is concluded that some of the extrafacial lesions may originate from the follicular infundibulum. No evidence of a virus infection was found using an antiserum to papilloma virus.     

Follicular infundibulum tumour presenting as cutaneous horn

Tumour of follicular infundibulum is an organoid tumour with a plate like growth attached to the epidermis with connection from the follicular epithelium. We are reporting such a case unusually presenting as cutaneous horn.     

Trichilemmal Tumor Undergoing Specific Keratinization

Numerous tumors with follicle-like direction of differentiation have been described. At least three of them connected to the overlying epidermis are related to the outer root sheath or trichilemma: the tumor of follicular infundibulum (Mehregan & Butler 1961) and the inverted follicular keratosis (Helwig 1955) or follicular poroma (Duperrat & Mascaro 1963) have been related to the infundibulum, the tricholemmoma (Headington & French 1961) to the lower outer root sheath. On the occasion of a case first diagnosed as proliferating trichilemmal cyst of the scalp, we think we have individualized a tumor exhibiting ability to undergo trichilemmal keratinization. We describe its histogenesis and stress its peculiarties compared with other lesions showing trichilemmal keratinization.     

Tumor of follicular infundibulum with unique features

Tumor of the follicular infundibulum is a rare benign cutaneous adnexal neoplasm with variable clinical presentation. In most cases the diagnosis is made with the help of histopathology, due to lack of a characteristic clinical presentation. The most common form is a solitary lesion, but it can be multiple or eruptive, then called infundibulomatose. This case report illustrates a patient with multiple lesions of tumor of the follicular infundibulum with bizarre aspect and atypical location.     

‘Congenital follicular melanocytic naevi’: a more appropriate term for spotted grouped pigmented naevi

We report two patients with an uncommon form of pigmented naevus consisting of grouped follicular papules. A biopsy taken from the lesions showed multiple naevus cells, predominantly around the hair follicles, with sparing of the eccrine glands. The clinicohistopathological term given for this condition is ‘spotted grouped pigmented naevi type I’, and has rarely been reported. We discuss the unusual morphology and differential diagnosis of this condition, and suggest that the term ‘congenital follicular melanocytic naevi’ is more appropriate for this presentation.     

嗜酸性脓疱性毛囊炎1例

患者男,22岁。面部红斑、丘疹和脓疱,伴脱屑3月余。面部可见数个红色或暗红色斑块和丘疹,顶部可见针尖大脓疱,伴破溃。血常规正常。皮损组织病理示:表皮角化过度、棘层轻度增厚。毛囊及真皮内可见大量以嗜酸性粒细胞为主的炎性细胞浸润,毛囊内见嗜酸性脓肿。     

Tumor of the follicular infundibulum with sebaceous differentiation

BACKGROUND: Tumor of the follicular infundibulum (TFI) is a relatively rare tumor which clinically presents as a solitary keratotic papule usually on the head and neck which on microscopic examination typically reveals a plate-like fenestrated epithelial tumor composed of pale staining cells. METHODS: We describe a new variant of TFI. An 80-year-old male with a history of multiple basal cell carcinomas and a squamous cell carcinoma presented with a 2-year history of a red, scaly, slightly elevated plaque on the lateral aspect of his right buttock. RESULTS: Histopathological examination revealed plate-like reticulate epithelial outgrowths of large and pale cells with foci of sebaceous differentiation and numerous colloid bodies. Differential diagnosis included superficial basal cell carcinoma with sebaceous and ductal differentiation, tumor of the follicular infundibulum, an unusual fibroepithelioma of Pinkus or an eccrine fibroadenoma with sebaceous differentiation. CONCLUSION: This case illustrates a hybrid adnexal tumor with histologic features common to both tumor of the follicular infundibulum and superficial epithelioma with sebaceous differentiation.     

Multiple tumors of follicular infundibulum with sweat duct differentiation

A 67-year-old man is reported with multiple tumors of follicular infundibulum containing ducts. Approximately 30 hypopigmented, scaling macules and minimally elevated papules were present on the face. Skin biopsy specimens from 5 representative lesions revealed similar findings. There was a proliferation of ramifying strands of pale-staining keratinocytes in the upper dermis showing connections with follicular infundibula of vellus follicles and epidermis. There was evidence of hair follicle differentiation with small follicular bulbs, papillary mesenchymal bodies, keratocysts, and occasional hair shafts in the tumor. These findings are characteristic of prior reports of TFI. Ducts were also present within the epithelial cords. Carcinoembryonic antigen, gross cystic disease fluid protein-15, epithelial membrane antigen, and S-100 protein were identified within the tumor. We theorize that the ductal elements within these TFI reflect the multipotential differentiating capacity of portions of infundibular epithelium.
Horn TD, Vennos EM, Bernstein BD, Cooper PH. Multiple tumors of follicular infundibulum with sweat duct differentiation.     

Lipid analysis of follicular casts from cyanoacrylate strips as a new method for studying therapeutic effects of antiacne agents

BACKGROUND: The cyanoacrylate follicular biopsy is an established method for the examination of the horny layer and quantitative assessment of microcomedones. We have optimized the method by separating follicular casts mechanically from the cyanoacrylate strips. OBJECTIVES: To use this method to analyse topical therapy-induced changes of the lipid composition in the sebaceous follicular infundibulum. METHODS: Both the follicular casts and the residual skin surface strip, the last representing a mixture of stratum corneum and surface lipids, were extracted twice with n-hexane-ethanol under ultrasonication, evaporated, redissolved in chloroform-methanol and separated by high-performance thin layer chromatography, using cholesterol sulphate, cerebroside, ceramide types 3 and 4, cholesterol, oleic acid, triolein, cholesterol oleate and squalene as standards. Identification was performed by computer-assisted densitometric analysis. Six patient groups receiving adapalene 0.1%, tretinoin 0.025%, clindamycin 1%, clindamycin 1% + tretinoin 0.025%, benzoyl peroxide 5% or benzoyl peroxide 5% + erythromycin 2% were investigated before and 12 weeks after application. RESULTS: A significant decrease in free fatty acid proportions combined with an increase in triglycerides was observed in the groups receiving antimicrobial therapy, supporting the hypothesis of lipolysis due to microbial colonization. The groups treated with topical retinoids showed an additional significant increase in ceramide subfractions, most probably reflecting their influence on epidermal keratinization. CONCLUSIONS: Our method proved suitable for the detection of quantitative and qualitative changes in lipid profiles of both infundibulum cast content and surface lipids. It enabled simple, non-invasive and objective assessment of the most relevant lipid classes in the sebaceous infundibulum, and efficient monitoring of drug effects on the follicular infundibulum.     

Folliculitis

Folliculitis is an inflammatory reaction in the superficial aspect of the hair follicle and can involve the follicular opening or the perifollicular hair follicles. The pilosebaceous unit of the follicle is divided into three compartments: the infundibulum (superficial part, outlined by the sebaceous duct), the isthmus (between the sebaceous duct and arrector pili protuberance), and the inferior segment (stem and hair bulb). This anatomical scheme forms the basis for any evaluation of the clinical manifestations of folliculitis. Most of the follicular conditions can be classified according to their anatomical location and histopathologic patterns. Clinically, the inflammation manifests as 1mm-wide vesicles, pustules, or papulopustules in acute cases; however, hyperkeratosis and keratotic plug formations are indicative of a chronic process. The presence of superficial pustules does not always imply an infectious origin, as there are many noninfectious types of folliculitis. In this review, we describe the different types of folliculitis based on their etiology, clinical manifestation, and treatment. We also discuss some newly described disorders and the latest information on their treatment.     

Multiple tumors of the follicular infundibulum with basocellular degeneration. Apropos of a case

A progressive papular eruption on the face, limbs and vulva had been present for seven years in a 38-year old female patient. Some papules were small and confluent while others were sparse, as in nodular prurigo. Histology showed massive proliferation of the follicular sheath epithelium, connected to the lower surface of the epidermis. The lesion formed a plate-like area very similar to that observed in superficial basal cell carcinoma and corresponding to a tumour of the follicular infundibulum. Remarkable features of this case were the large number of lesions, their photosensitivity (they became pruriginous and increased in size after exposure to the sun), the presence of eccrine sweat glands beneath a skin lesion of the thigh, the basal cell degeneration of two lesions and the slight improvement observed after etretinate therapy. To our knowledge, such findings have not yet been reported in tumours of the follicular infundibulum.     

Multiple infundibular tumours of the head and neck

A condition of multiple benign and sometimes self-healing infundibular tumours of the skin is described. It effects the sun-exposed areas of the head and neck in Caucasians. The individual lesions consist of a cluster of thick pockets, representing in many details the supra-sebaceous portions of the follicular unit. Follicular poroma, tumours of the deeper part of the follicular infundibulum, virus warts, inverted follicular keratosis and prurigo nodules do not correspond adequately with the appearance described in the present series of six cases.     

Follicular granular parakeratosis

An 83-year-old patient presented herself with a ten-year history of keratotic papules on her trunk. A biopsy of this process revealed granular parakeratosis confined to the infundibulum of a follicle. Exclusive follicular involvement in granular parakeratosis has not been previously described.     

Localized pemphigus foliaceus exclusively involving the follicular infundibulum: a novel peau d'orange appearance

Localized pemphigus foliaceus (PF) clinically presents as red plaques with scale and crust due to acantholysis of the epidermis. The follicular infundibulum shows acantholysis, but usually with epidermal acantholysis or at least erosion. Localized PF exclusively involving the follicular infundibulum, which shows a peau d'orange appearance, has never been reported. We describe a patient with a red plaque and peau d'orange appearance on the cheek for 20 years. Dyskeratotic acantholysis in the follicular infundibulum was overlooked when the first biopsy specimen was obtained, and a disseminated lesion developed soon after, which led to the diagnosis. Although a peau d'orange appearance is a rare clinical manifestation of PF, PF should be considered as the differential diagnosis on the basis of this appearance, especially when the lesion persists on the face for long periods.     

Tumor of follicular infundibulum.

Tumor of the follicular infundibulum is a rare, benign proliferative follicular disorder. A case of multiple lesions in a 37-year-old woman is reported. The diagnosis was made histologically.     

Acanthokeratolytic epidermal nevus: acanthokeratolysis is hereditary, not the nevus

Epidermal naevus of the acanthokeratolytic (epidermolytic) type is a mosaic birth defect. The underlying mutation may also be present in the gonads and can then be transmitted to the next generation. The affected child, however, will always show a diffuse involvement of the entire body in the form of bullous congenital ichthyosiform erythroderma. In other words, the phenotype can be transmitted, but not the mosaic. This explains why acanthokeratolytic epidermal naevus always affects the parent and never the child when it is observed in a family together with bullous congenital ichthyosiform erythroderma.     

Disseminate and persistent infundibulo-folliculitis

An 18-year-old girl presented with a persistent skin eruption of 6 years duration. She had skin-coloured follicular papules involving the trunk, proximal extremities, neck and face. Histopathology revealed spongiosis of the follicular infundibulum and infiltration with lymphocytes and neutrophils. Treatment with oral vitamin A and topical retinoic acid was ineffective.     

Cornoid lamellae associated with follicular infundibulum and acrosyringium in porokeratosis

Skin lesions of porokeratosis consist of an atrophic center bordered by a peripheral grooved keratotic ridge that corresponds histopathologically to the cornoid lamella. Originally porokeratosis was named based on the assumption that the columns of parakeratosis emerge from the ostia of eccrine ducts. Despite this, it is generally accepted that the cornoid lamellae are rarely related to the acrosyringium. We recently encountered two cases of porokeratosis, where the cornoid lamellae were related to the follicular infundibulums. Therefore, we analyzed the location of the cornoid lamellae in 86 lesions of porokeratosis from 73 patients from our archives. We found that many cornoid lamellae are also detected at follicular infundibulum and acrosyringium. The existence of so many cornoid lamellae at follicular infundibulum and acrosyringium inside the plaques cannot be explained by pure coincidence and may be more than fortuitous.