- Author: Patrick S Rush, DO; Chief Editor: William D James, MD more...
Cutaneous horn is a clinical diagnosis referring to a conical projection of cornified material above the surface of the skin that resembles a miniature horn. Historically, it is also referred to by its Latin name, cornu cutaneum, and less commonly and more eponymously, as cornu cutaneum of Rokitansky, after the German pathologist Baron Carl von Rokitansky.
The horn is composed of compacted keratin. The base of the horn may be flat, nodular, or crateriform. 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 or bleeding at the base and lesions of larger size, however, favor malignancy.
Historically, London surgeon Everard Home was credited with the earliest descriptions of cutaneous horns in 1791. However, cases from as early as the 16th and 17th centuries have been described in the medical literature. Most notable among these was by the Danish anatomist Thomas Bartholin in 1670.
The image below depicts a typical presentation of a cutaneous horn.
See Nonmelanoma Skin Cancers You Need to Know, a Critical Images slideshow, to help correctly identify these lesions.
Cutaneous 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. While the protruding, compact keratin may be the most prominent clinical feature, it is the process at the base of the lesion that is of most importance.
Most often, this is a benign verruca or seborrheic keratosis; however, cutaneous horns complicate a number of conditions, including premalignant actinic keratoses and frank malignancy. More than half of all of the inciting lesions at the base of cutaneous horns are benign, and a further 23-37% are derived from actinic keratoses. A malignancy has been reported at the base of a cutaneous horn in up to 20% of lesions.[3, 4, 5, 6]
The true pathobiology for the formation of cutaneous horns over each underlying base lesion remains unknown.
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 disease, Kaposi sarcoma, keratoacanthoma,[15, 16] malignant melanoma, Paget disease, renal cell carcinoma, sebaceous carcinoma,[20, 21] and squamous cell carcinoma.
While these lesions are almost uniformly referred to as “rare” in the literature, neither the true incidence nor prevalence has been well described.[15, 23]
Cutaneous horns often cause little physical discomfort unless struck or if arising in areas prone to physical irritation. Cosmetically, however, they can cause significant concern for the patient, as they can be socially disconcerting. In fact, historically, prior to modern medicine, people with giant cutaneous horns had been persecuted as having “magical power” and were often displayed as sideshow attractions.[15, 2]
The 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.[24, 25] Tenderness at the base of the lesion is often a clue to the presence of a possible underlying squamous cell carcinoma. Bleeding at the base of the lesion, as well as larger size, have been suggested as an indication of underlying malignancy.[2, 26]
Because of the proportion of cutaneous horns that arise from actinic keratoses and squamous cell carcinomas, races with lighter complexions tend to be preferentially affected. However, several cases of cutaneous horns have been reported in patients of darker complexion, including those of African and Mexican descent.[1, 27, 28]
A 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, and some studies also have shown premalignant lesions to be slightly more common in men.
The 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.
Durkee S. Human Horn (Cornu Cutaneum of Rokitansky). Boston Med Surg J. 1866 Feb. 74:9-11.
Bondeson J. Everard Home, John Hunter, and cutaneous horns: a historical review. Am J Dermatopathol. 2001 Aug. 23(4):362-9. [Medline].
Fatani MI, Hussain WM, Baltow B, Alsharif S. Cutaneous horn arising from an area of discoid lupus erythematosus on the scalp. BMJ Case Rep. 2014 Apr 3. 2014:[Medline].
Jhuang JY, Liao SL, Tsai JH, Chang HC, Kuo KT, Liau JY. Extraocular well-differentiated sebaceous tumors with overlying cutaneous horns: four tumors in three patients. J Cutan Pathol. 2014 Aug. 41(8):650-6. [Medline].
Srebrnik A, Wolf R, Krakowski A, Baratz M. Cutaneous horn arising in cutaneous leishmaniasis. Arch Dermatol. 1987 Feb. 123(2):168-9. [Medline].
Dabski K, Stoll HL. Cutaneous horn arising in chronic discoid lupus erythematosus. Arch Dermatol. 1985 Jul. 121(7):837-8. [Medline].
Goette DK. Cutaneous horn overlying granular cell tumor. Int J Dermatol. 1987 Nov. 26(9):598-9. [Medline].
Findlay RF, Lapins NA. Pyogenic granuloma simulating a cutaneous horn. Cutis. 1983 Jun. 31(6):610-2. [Medline].
Brownstein MH, Shapiro EE. Trichilemmomal horn: cutaneous horn overlying trichilemmoma. Clin Exp Dermatol. 1979 Mar. 4(1):59-63. [Medline].
Gould JW, Brodell RT. Giant cutaneous horn associated with verruca vulgaris. Cutis. 1999. 64:111-2. [Medline].
Sandbank M. Basal cell carcinoma at the base of cutaneous horn (cornu cutaneum). Arch Dermatol. 1971 Jul. 104(1):97-8. [Medline].
Wollina U, Schonlebe J. Giant keratoacanthoma-like cutaneous horn of the upper leg: A case report. Acta Dermatovenerol Alp Panonica Adriat. 2010. 19(2):29-30. [Medline].
Cristobal MC, Urbina F, Espinoza A. Cutaneous horn malignant melanoma. Dermatol Surg. 2007 Aug. 33(8):997-9. [Medline].
Dabski K, Stoll HL Jr. Paget's disease of the breast presenting as a cutaneous horn. J Surg Oncol. 1985 Aug. 29(4):237-9. [Medline].
Peterson JL, McMarlin SL. Metastatic renal-cell carcinoma presenting as a cutaneous horn. J Dermatol Surg Oncol. 1983 Oct. 9(10):815-8. [Medline].
Brauninger GE, Hood CI, Worthen DM. Sebaceous carcinoma of lid margin masquerading as cutaneous horn. Arch Ophthalmol. 1973 Nov. 90(5):380-1. [Medline].
Kitagawa H, Mizuno M, Nakamura Y, Kurokawa I, Mizutani H. Cutaneous horn can be a clinical manifestation of underlying sebaceous carcinoma. Br J Dermatol. January 2007. 156(1):180-2. [Medline].
Korkut T, Tan NB, Oztan Y. Giant cutaneous horn: a patient report. Ann Plast Surg. 1997 Dec. 39(6):654-5. [Medline].
Sathyanarayana SA, Deutsch GB, Edelman M, Cohen-Kashi KJ. Cutaneous horn: a malignant lesion? A brief review of the literature. Dermatol Surg. 2012 Feb. 38(2):285-7. [Medline].
Solivan GA, Smith KJ, James WD. Cutaneous horn of the penis: its association with squamous cell carcinoma and HPV-16 infection. J Am Acad Dermatol. 1990 Nov. 23(5 Pt 2):969-72. [Medline].
Vera-Donoso CD, Lujan S, Gomez L, Ruiz JL, Jimenez Cruz JF. Cutaneous horn in glans penis: a new clinical case. Scand J Urol Nephrol. 2009. 43(1):92-3. [Medline].
Yu RC, Pryce DW, Macfarlane AW, Stewart TW. A histopathological study of 643 cutaneous horns. Br J Dermatol. 1991 May. 124(5):449-52. [Medline].
Leppard W, Loungani R, Saylors B, Delaney K. Mythology to reality: case report on a giant cutaneous horn of the scalp in an African American female. J Plast Reconstr Aesthet Surg. 2014 Jan. 67(1):e22-4. [Medline].
Nthumba PM. Giant cutaneous horn in an African woman: a case report. J Med Case Rep. 2007 Dec 5. 1:170. [Medline].
Mencia-Gutierrez E, Gutierrez-Diaz E, Redondo-Marcos I, Ricoy JR, Garcia-Torre JP. Cutaneous horns of the eyelid: a clinicopathological study of 48 cases. J Cutan Pathol. 2004 Sep. 31(8):539-43. [Medline].
Vano-Galvan S, Marques A, Munoz-Zato E, Jaen P. A facial cutaneous horn. Cleve Clin J Med. 2009 Feb. 76(2):92-5. [Medline].
Uchiyama N, Shindo Y, Saida T. Perforating pilomatricoma. J Cutan Pathol. 1986 Aug. 13(4):312-8. [Medline].
Mantese SA, Diogo PM, Rocha A, Berbert AL, Ferreira AK, Ferreira TC. Cutaneous horn: a retrospective histopathological study of 222 cases. An Bras Dermatol. 2010 Apr. 85(2):157-63. [Medline].