Horn, cutaneous

May appear clinically as a cutaneous horn due to the significant hyperkeratosis. 

Figure 23-22 Types of verruca (A) verruca vulgaris, (B) verruca plana, and (C) cutaneous horn. (Courtesy Lloyd Pate, O.D.)...

Verruca vulgaris, verruca plana, and cutaneous horn are forms of viral warts produced by the human papilloma virus (HPV).They are caused by an overgrowth of normal epithelium that may become keratinized and pigmented. Because they occur only in the superficial tissue layer, the body does not recognize them as foreign and therefore does not mount an immune reaction. They are most commonly found in children and young adults and may... 

Thermal cautery uses heat to destroy tissue. A similar technique, called fulguration, uses electric current to destroy tissue. Heat cautery is performed using a disposable heat cautery unit and is used to stop bleeding during sm-gical procedures and to remove skin tags, cutaneous horns, and pedunculated verrucae. It can also be used to occlude a punctum, reposition an ectopic punctum with resultant epiphora, and alleviate trichiasis as a result of spastic entropion. 

Rabbit (Australian albino) 15 wk 3 x/wk 10 M Percent (%) (CEL papillomas, squamous cell carcinoma,s keratoacanthomas cutaneous horns) Kligman and Kligman 1994 coal tar... 

Crude coal tar (10, 25, and 100%) in petrolatum was applied to the ear of male Australian albino rabbits (3 per group) 3 times/week for 15 weeks (Kligman and Kligman 1994). Crude coal tar was both comedogenic and carcinogenic at all doses tested (10, 25, or 100%). Tumors developed as early as 1-2 weeks after 3 weeks of treatment with 10% coal tar. The tumors were classified as papillomas, squamous cell carcinomas, keratoacanthomas, and cutaneous horns, and became extremely numerous with longer treatment. 

The earliest lesions that can be detected after only a few months of exposure to pitch are small raised, flattened keratoses (1-5 mm) on the dorsal aspects of the hands, forearms, or face. These lesions may resemble flat warts and are usually stable over many years. Rarely, hypertrophic growth may result in formation of cutaneous horns (Ross 1948). Pitch keratoses (squamous keratoses) were slightly more common in pitch workers -12% compared with 10% in the control group (Hodgson and Whitely 1970). 

Thick epidermal lesions not amenable to peel alone, such as seborrheic keratoses, cutaneous horn, and thick actinic keratoses... 

Afferent input from cutaneous and visceral nociceptors is known to converge on spinal neurons, which accounts for the referral of pain between visceral and cutaneous structures (e.g. cardiac pain gets referred to the chest and left upper arm in patients suffering from angina pectoris). Projection neurons in the spinal dorsal horn project to cell nuclei in supraspinal areas such as the thalamus, brainstem and midbrain. Of these, the synaptic junctions in the thalamus play a very important role in the integration and modulation of spinal nociceptive and non-nociceptive inputs. Nociceptive inputs are finally conducted to the cortex where the sensation of pain is perceived (Fig. 1). The mechanisms via which the cortex processes nociceptive inputs are only poorly understood. 

Figure 8.3 Referred pain. The mechanism of referred pain involves convergence of visceral afferent neurons and cutaneous afferent neurons with the same second-order neurons in the dorsal horn of the spinal cord. In this example, the pain of angina that originates in the heart is referred to the left arm.

Are T Cells Involved in Specific Immune Responses to Autoantigens in Atopic Dermatitis Autoimmune phenomena to human self-proteins may also contribute to the pathophysiology of atopic dermatitis. IgE against autoantigens such as Horn SI-4 have been shown to stimulate type 1 hypersensitivity reactions which in turn may contribute to the clinical cutaneous reactions in atopic dermatitis [15]. Autoallergens induce the proliferation of CLA+ autoreactive T cells derived... 

Radhakrishnan, V. and Henry, J. L. Novel substance P antagonist, CP-96345, blocks responses of cat spinal dorsal horn neurons to noxious cutaneous stimulation and to substance P, Neurosci. Lett. 1991, 132, 39-43. 

Johnson B, Horn T, Sander C, Kohler S, Smoller BR. Expression of stratum corneum chymotryptic enzyme in ichthyoses and squamoproliferative processes. J Cutan Pathol 2003 30 358-362. 

Rest EB, Horn TD. Immunophenotypic analysis of benign and malignant cutaneous lymphoid infiltrates. Clin Dermatol. 1991 9 261-272. 

Woolf CJ, King AE (1989) Subthreshold components of the cutaneous mechanoreceptive fields of dorsal horn neurons in the rat lumbar spinal cord. J Neurophysiol 62 907-916 Woolf CJ, King AE (1990) Dynamic alterations in the cutaneous mechanoreceptive fields of dorsal horn neurons in the rat spinal cord, J Neurosci 10 2717-2726 Woolf CJ, Salter MW (2000) Neuronal plasticity Increasing the gain in pain. Science 288 1765-1769... 

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