Cutaneous sensory neurons that detect noxious stimuli project to the dorsal horn of the spinal cord, while those innervating muscle stretch receptors project to the ventral horn. DRG11, a paired homeodomain transcription factor, is expressed in both the developing dorsal horn and in sensory neurons, but not in the ventral spinal cord. Mouse embryos deficient in DRG11 display abnormalities in th...

The differentiation and migration of superficial dorsal horn neurons and subsequent ingrowth of cutaneous afferents are crucial events in the formation of somatosensory circuitry in the dorsal spinal cord. We report that the differentiation and migration of the superficial dorsal horn neurons are regulated by the LIM homeobox gene Lmx1b, and its downstream targets Rnx and Drg11, two transcripti...

A cutaneous horn is a conical, dense, hyperkeratotic protrusion that often appears similar to the horn of an animal. It is a morphologic designation referring to an unusually cohesive keratinized material, not a true pathologic diagnosis. Cutaneous horns occur in association with, or as a response to, a wide variety of underlying benign, pre-malignant, and malignant cutaneous diseases. The most...

Cutaneous horn is a conical hyperkeratotic projection of the skin composed of compact keratin. A wide range of pathologic conditions may be found at its base, including a significant proportion of malignant tumors. A notable, giant cutaneous horn uncovering a keratoacanthoma/well-differentiated squamous cell carcinoma is presented, highlighting the importance of histopathological examination to...

Cutaneous horns are uncommon lesions consisting of keratotic material, resembling that of an animal horn. They account for 4% of all eyelid tumors. We report a case of giant cutaneous horn (2 × 1.75 cm) of 4-year duration arising from the right lower lid. Growth excision with direct closure of the defect was done. Histopathological examination revealed it to be well-differentiated squamous cell...

Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine malignancy, which usually presents as an asymptomatic, rapidly growing, firm nodule on sun-damaged skin. We present a 93-year-old female who presented with a "cutaneous horn" on the face. On excision, histologic examination revealed a combined squamous cell carcinoma in situ with underlying MCC. Merkel cell polyomavirus immunohistoc...

The current report presents the case of a 43-year-old male suffering from a penile cutaneous horn. A surgical excision of the lesion was performed and histopathology demonstrated hyperkeratosis, dyskeratosis and epithelial hyperplasia. The cutaneous horn progressed to squamous cell carcinoma <1.5 months following surgery and a partial penectomy was conducted. The International Index of Erectile...