You are in: eMedicine Specialties > Dermatology > BENIGN NEOPLASMS Cutaneous HornArticle Last Updated: Dec 15, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Fiona Larsen, MB, ChB, Dermatopathology Fellow, Department of Dermatology, Division of Dermatopathology, University of Texas Southwestern Medical Center at Dallas Coauthor(s): Clay J Cockerell, MD, Director, Clinical Professor, Department of Dermatology, Division of Dermatopathology, University of Texas Southwestern Medical Center; Nancy Silvis, MD, Assistant Professor of Clinical Medicine, Section of Dermatology, Medical Director of Dermatology Clinic, University of Arizona Health Sciences Center; Consulting Staff, Adobe Dermatology Editors: R Stan Taylor, MD, Professor of Dermatology, University of Texas Southwestern Medical School; Director of Skin Surgery and Oncology Clinic, Department of Dermatology, University of Texas Southwestern Medical Center; David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Director, Division of Dermatology, Scott and White Clinic; Director Dermatology Residency Training Program, Scott and White Clinic; Edward F Chan, MD, Clinical Assistant Professor, Department of Dermatology, University of Pennsylvania School of Medicine; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; William D James, MD, Paul R Gross Professor of Dermatology, University of Pennsylvania School of Medicine; Vice-Chair, Program Director, Department of Dermatology, University of Pennsylvania Health System Author and Editor Disclosure Synonyms and related keywords: cornu cutaneum INTRODUCTIONSection 2 of 9
  BackgroundCutaneous horn is a clinical diagnosis referring to a conical projection above the surface of the skin that resembles a miniature horn. The base of the horn may be flat, nodular, or crateriform. The horn is composed of compacted keratin. Various histologic lesions have been documented at the base of the keratin mound, and histologic confirmation is often necessary to rule out malignant changes. No clinical features reliably distinguish between benign and malignant lesions. Tenderness at the base and lesions of larger size favor malignancy. PathophysiologyCutaneous horns usually arise on sun-exposed skin but can occur even in sun-protected areas. The hyperkeratosis that results in horn formation develops over the surface of a hyperproliferative lesion. Most often, this is a benign verruca or seborrheic keratosis; or it could be a premalignant actinic keratosis. A malignancy has been reported at the base of a cutaneous horn in up to 20% of lesions. More than half of all cutaneous horns are benign. Benign lesions associated with cutaneous horns include angiokeratoma, angioma, benign lichenoid keratosis, cutaneous leishmaniasis, dermatofibroma, discoid lupus, infundibular cyst, epidermal nevus, epidermolytic acanthoma, fibroma, granular cell tumor, inverted follicular keratosis, keratotic and micaceous pseudoepitheliomatous balanitis, organoid nevus, prurigo nodularis, pyogenic granuloma, sebaceous adenoma, seborrheic keratosis, trichilemmoma, and verruca vulgaris. Lesions with premalignant or malignant potential that may give rise to cutaneous horns include adenoacanthoma, actinic keratosis, arsenical keratosis, basal cell carcinoma, Bowen's disease, Kaposi sarcoma, keratoacanthoma, Paget's disease, renal cell carcinoma, sebaceous carcinoma, solar keratosis, and squamous cell carcinoma. Mortality/MorbidityThe lesion at the base of the keratin mound is benign in the majority of cases. Malignancy is present in up to 20% of cases, with squamous cell carcinoma being the most common type. The incidence of squamous cell carcinoma increases to 33% when the cutaneous horn is present on the penis. Tenderness at the base of the lesion is often a clue to the presence of a possible underlying squamous cell carcinoma. RaceBecause of the proportion of cutaneous horns that arise from actinic keratoses and squamous cell carcinomas, races with lighter complexions tend to be preferentially affected. SexA sex predilection for cutaneous horn has not been shown consistently. In men, the rate of malignancies at the base of the lesion is increased when compared with age-matched women. AgeThe peak occurrence of cutaneous horn is in persons aged 60 years to mid 70s. Lesions with malignancy at the base occur more frequently in patients aged 70 years or older. CLINICALSection 3 of 9
HistoryCutaneous horns usually are asymptomatic. Because of their excessive height, they can be traumatized. This may result in inflammation at the base with resulting pain. Rapid growth may occur. PhysicalThe distribution of cutaneous horn usually is in sun-exposed areas, particularly the face, pinna, nose, forearms, and dorsal hands. It is a hyperkeratotic papule with the height greater than one-half the width of the base. Usually a cutaneous horn is several millimeters long. CausesMalignant lesions at the base of the horn usually are squamous cell carcinoma, although basal cell carcinoma has been rarely reported. These are predominately precipitated by ultraviolet radiation. Rare tumors at the base include Paget disease of the breast, sebaceous adenoma, and granular cell tumor. The premalignant lesion, actinic keratosis, is a frequent finding at the base. The human papilloma virus most frequently causes infectious etiology resulting in a verruca vulgaris. Molluscum contagiosum of the poxvirus group occasionally has formed a cutaneous horn. The only other infectious cause has been leishmaniasis. Benign idiopathic causes are frequent and include seborrheic keratosis, epidermal nevus, trichilemmal cyst, trichilemmoma, prurigo nodule, and intradermal nevus. DIFFERENTIALSSection 4 of 9
Warts, Nongenital WORKUPSection 5 of 9
Lab Studies
Histologic FindingsThe horn is composed of compact hyperkeratosis, which may be either orthokeratotic or parakeratotic in nature. Associated acanthosis is a common finding. The base will display features of the pathologic process responsible for the underlying lesion. TREATMENTSection 6 of 9
Surgical Care
FOLLOW-UPSection 7 of 9
Further Outpatient Care
MULTIMEDIASection 8 of 9
REFERENCESSection 9 of 9
Article Last Updated: Dec 15, 2006 | |||||||||||||||||||||
