Humans with inherited T cell CD28 deficiency are susceptible to skin papillomaviruses but are otherwise healthy.

We study a patient with the human papilloma virus (HPV)-2-driven "tree-man" phenotype and two relatives with unusually severe HPV4-driven warts. The giant horns form an HPV-2-driven multifocal benign epithelial tumor overexpressing viral oncogenes in the epidermis basal layer. The patients are unexpectedly homozygous for a private CD28 variant. They have no detectable CD28 on their T cells, with the exception of a small contingent of revertant memory CD4+ T cells. T cell development is barely affected, and T cells respond to CD3 and CD2, but not CD28, costimulation. Although the patients do not display HPV-2- and HPV-4-reactive CD4+ T cells in vitro, they make antibodies specific for both viruses in vivo. CD28-deficient mice are susceptible to cutaneous infections with the mouse papillomavirus MmuPV1. The control of HPV-2 and HPV-4 in keratinocytes is dependent on the T cell CD28 co-activation pathway. Surprisingly, human CD28-dependent T cell responses are largely redundant for protective immunity.

Penile Cutaneous Horn in a 22-month-old Child: A Rare Case Report.

Cutaneous horn is a horn-like hyperkeratotic lesion. Its presence over penis is unusual and rare. Herein, we report a case of horn of penis in a 22-month-old child.

Panfolliculoma with an endophytic architecture resembling a hair follicle: a report of three cases.

Panfolliculoma is a benign follicular tumor comprised of all components of the hair follicle. We report three cases of panfolliculoma with a solid, endophytic architecture, which at scanning magnification had the profile of a hair follicle. The epithelial components included uniform dark blue germinative cells, matrical cells, clear cells and cells containing trichohyaline granules. All the cases also had a central hyperkeratotic horn resembling a hair shaft. Two patients were female and one was male. Two lesions were located on the head and neck, and one was located on the leg. Clinical differential diagnoses included basal cell carcinoma, foreign body and cyst.

Extraocular well-differentiated sebaceous tumors with overlying cutaneous horns: four tumors in three patients.

BACKGROUND: Sebaceous tumors are adnexal neoplasms showing sebocytic differentiation. They range from benign to malignant and are associated with Muir-Torre syndrome (MTS). Several clinical and histopathological features associated with MTS have been described. Sebaceous tumors with an overlying cutaneous horn are extremely rare. METHODS: Hematoxylin and eosin-stained slides were retrospectively reviewed to identify sebaceous tumors with marked hyperkeratosis, a condition that is often associated with cutaneous horns. Clinical correlation and mismatch repair protein immunohistochemical studies were then conducted. RESULTS: Four tumors from three patients were identified in our archive. Three were classified as sebaceous adenomas, and the fourth was considered as a borderline sebaceous tumor favoring well-differentiated sebaceous carcinoma. All cases showed loss of expression of mismatch repair proteins (three tumors from two patients exhibited lost expression of MSH2 and MSH6, and the fourth exhibited lost expression of MLH1 and PMS2). Additionally, one patient presented characteristic clinical manifestations of MTS, including multiple sebaceous adenomas and visceral carcinomas. CONCLUSIONS: We suggest that extraocular well-differentiated sebaceous neoplasms with overlying cutaneous horns may be an indication of underlying mismatch repair protein deficiency and potential MTS. This distinctive morphology might be an exaggerated combination of other features associated with MTS, i.e. keratoacanthoma-like architecture and extensive holocrine secretion.

Pilomatricoma presenting as a giant cutaneous horn in an 8-year-old child: A case report and literature review.

Pilomatricoma is an uncommon benign adnexal tumor of childhood. We report a case of pilomatricoma presenting as a large, recurrent painful cutaneous horn on the neck of an 8-year-old boy treated with surgical excision. On histopathology, classical features of pilomatricoma along with transepidermal elimination and perforation were shown. We propose that perforating pilomatricoma and pilomatrical horn represent equivalent clinical and pathological entities. The diagnosis of perforating pilomatricoma should be considered in pediatric patients presenting with a cutaneous horn.

Unraveling the Enigma: A Report on a Rare Case of Cutaneous Horn, an Extraordinary Dermatological Occurrence.

A cutaneous horn is a rare, hyperkeratotic, projecting lesion that can be mostly found in sun-exposed areas of the skin. The base of the lesions can reveal an underlying malignancy. They can also be associated with several benign or pre-malignant dermatologic conditions. A biopsy of the base of the lesion and histopathological analysis are needed to confirm the diagnosis. Management depends on the underlying disease; however, surgical excision is the preferred treatment method.

Acquired Digital Fibrokeratoma.

Acquired digital fibrokeratoma is a rare, benign tumor that mostly occurs on the fingers and toes and may appear to be a supernumerary rudimentary digit. It generally affects adult men and appears as a dome-shaped papule although it can also be elongated or pedunculated. Trauma is believed to be a triggering factor in some cases. We report a male patient with an acquired digital fibrokeratoma on a finger, shaped like a cutaneous horn, and a history of minimal repeated trauma and spontaneous remissions not previously described in the literature.

Verruca Vulgaris-Associated Cutaneous Horn: A Case Report.

A cutaneous horn is a yellow or white-colored conical projection made up of complex keratin that arises from the surface of the skin. It is usually diagnosed clinically but requires histologic examination to rule out malignancy or determine the underlying lesion. Verruca vulgaris, a human papillomavirus-associated lesion, is a very common benign underlying lesion. We present a case of an 80-year-old female who presented with a cutaneous horn on a unique location, the proximal interphalangeal joint (PIP) of her left fourth digit. Post-excision biopsy revealed a diagnosis of a verruca vulgaris-associated cutaneous horn.

Cutaneous Horn: A Masquerade to Underlying Keratotic Basal Cell Carcinoma.

Cutaneous horns are uncommon skin tumors consisting of keratotic material infrequently found on eyelids. We report the case of a 65-year-old male with a two-month history of cutaneous horn arising from the right lower eyelid. Histopathological examination following the excision biopsy disclosed a keratotic basal cell carcinoma (BCC). Basal cell carcinomas are slow-growing lesions with a history ranging from months to years. The keratotic form of basal cell carcinoma is a less common presentation of a cutaneous horn. A cutaneous horn is usually derived from an underlying lesion that may be benign, premalignant, or malignant. The diagnostic dexterity of keratotic BCC emphasizes the importance of histopathological confirmation in establishing the diagnosis and modifying management. To the best of our knowledge, this is the first case report of a keratotic basal cell carcinoma masquerading as a small cutaneous horn with such a short duration.

Giant Cutaneous Horn: Is It a Tip of An Iceberg? Two Case Reports and a Review of Literature.

Cutaneous horns are uncommon lesions which consist of proliferation of keratotic material resembling that of an animal horn. This lesion most commonly occurs in sun-exposed areas, particularly the face, ear, nose, forearms and dorsum of hands. The purpose of the study was to highlight the atypical presentation of squamous cell carcinoma as a giant cutaneous horn along with the review of literature. Case details were obtained from hospital records and clinical and histopathological findings were noted. Herein we report two cases of giant cutaneous horn associated with an underlying carcinoma presenting at an uncommon site. Both the patients were adults and had a chronic history of a skin lesion over the affected sites. Wide local excision was performed in both cases and histopathological examination confirmed the diagnosis of a cutaneous horn with a well differentiated squamous cell carcinoma at the base of the horn. Cutaneous horns are commonly associated with benign lesions and rarely with malignant conditions. It is imperative to biopsy the base of the horn to rule out any underlying malignancy. Proper surgical excision with adequate margins is the preferred treatment in case of an underlying malignancy.

Facial cutaneous horn in three different conditions: A highlight of a malignancy risk.

INTRODUCTION: Cutaneous horns are nodules composed of compact keratin that project above the surface of the skin. The purpose of this work is to show the danger that can constitute the cutaneous horns. PRESENTATION OF CASES: In this paper, the authors report series of three cases of facial cutaneous horns, which were respectively diagnosed as trichilemmal horn in a 79-years old patient, a cutaneous horn underlying epidermoid carcinoma in a 59-years old patient, and a basal cell carcinoma in an 80-years old patient. All patients were treated by surgical excision. DISCUSSION: Cutaneous horns are generally asymptomatic and generate above all cosmetic disorders placing the patient in great social discomfort, thus prompting him to seek medical advice. CONCLUSION: They emphasize the need for careful management of these lesions because of the high incidence of malignant histology.

Cutaneous Horn of the Glans.

Cutaneous horn is a protuberance constituted by compact keratinous material, with a hard consistence similar to a horn, which occurs more frequently in photoexposed areas. The authors describe a case of cutaneous horn on the glans considered a rare location. Verrucous carcinoma was the histopathological diagnosis of the base of the horn and lichen sclerosis, the precursor lesion.

A Curious Case of Cutaneous Horn.

Cutaneous horns are uncommon lesions that occur as conical projections in various sun-exposed parts of the body. They are made of hyperkeratotic material and look similar to animal horns. These lesions lack a central bony core that differentiates them from the animal horns. They are frequently associated with various benign, premalignant, and malignant lesions, and therefore carry a clinical significance. We present a case of a 58-year-old gentleman who presented with a conical projection over the center of the forehead, which was clinically diagnosed as a cutaneous horn. Excision of the horn along with the base was done, and the histopathology revealed benign seborrheic keratosis as the underlying lesion. The excision of small lesions along with their bases or biopsy of the base of large lesions is of paramount importance in the management of cutaneous horns.

Penile cutaneous horn.

Cutaneous horns are cornified hyperkeratotic lesions on the skin, usually present on photo-exposed areas such as the face and scalp. Its presence on the penis is very rare. Here, we report a 35-year-old male presenting with penile cutaneous horn with successful management with wide local excision along with a review of other modalities of treatment of this rare entity.

Cutaneous horn: A rare subtype of juvenile xanthogranuloma.

Because of variability in the JXG shape and the extensive range of a cutaneous horn differential diagnosis, dermatologists should keep this diagnosis in their mind in the time of encountering with infants or children cases of cutaneous horn.

Factors related to delayed treatment: A case report of a huge cutaneous horn and review of the literature.

We present a case of a man with a giant cutaneous horn over his frontal region. This case has been presented for the size of the lesion, due to delayed treatment, and to illustrate the reasons why the growth of this lesion has been possible in a western country, in the 21st century. It was a solitary, not painful lesion which caused significant aesthetic problems. The diagnosis was based on an ultrasonographic study and the treatment of choice was a surgical excision. This case is an opportunity to review the literature about the cutaneous horns, to talk about the main causes of delayed diagnosis and treatment of cutaneous lesions and, to define the role of the specialist in the assessment of emotions and patient support.