Keratocanthoma

Dermatology

Clinicals - History

Fact Explanation
Skin swelling Keratoacanthoma is a benign epithelial neoplasm
which originates in the epithelium of the hair follicle above the sebaceous glands. Sometimes it is considered as a form of squamous cell carcinoma. Keratoacanthoma grows rapidly over a few weeks to months, followed by a slow spontaneous resolution over 4 months to 1 year. The lesion mostly occurs on sun-exposed areas such as face, neck, and dorsum of hands and forearms. They are usually solitary and begin as firm, round, skin-coloured or reddish papule. This initial papule rapidly progresses to a dome-shaped nodules with a smooth shiny surface.
Skin swelling
Keratoacanthoma is a benign epithelial neoplasm
which originates in the epithelium of the hair follicle above the sebaceous glands. Sometimes it is considered as a form of squamous cell carcinoma. Keratoacanthoma grows rapidly over a few weeks to months, followed by a slow spontaneous resolution over 4 months to 1 year. The lesion mostly occurs on sun-exposed areas such as face, neck, and dorsum of hands and forearms. They are usually solitary and begin as firm, round, skin-coloured or reddish papule. This initial papule rapidly progresses to a dome-shaped nodules with a smooth shiny surface.
Ulceration With time, the papule grows rapidly, reaching a large size within days or weeks. And then it begin to necrose resulting a central crater of ulceration. Ulceration
With time, the papule grows rapidly, reaching a large size within days or weeks. And then it begin to necrose resulting a central crater of ulceration.
Keratin horn Keratin plug may project like a horn instead of causing an ulceration. Keratin horn
Keratin plug may project like a horn instead of causing an ulceration.
Scars If nor excised, the ulceration leaves a residual scar. Scars
If nor excised, the ulceration leaves a residual scar.
Risk factors Presence of particular strains of the wart virus (human papillomavirus) that cause viral warts, frequent exposure to the Sunlight and chemical carcinogens, trauma, industrial workers exposed to pitch and tar, immuno-depletion , chronic ulcers and previous skin cancers are predisposing. Peak incidence occurs in those aged over 60 years. It is rare in young adults and in darker-skinned patients. Males are twice as often affected as females. Risk factors
Presence of particular strains of the wart virus (human papillomavirus) that cause viral warts, frequent exposure to the Sunlight and chemical carcinogens, trauma, industrial workers exposed to pitch and tar, immuno-depletion , chronic ulcers and previous skin cancers are predisposing. Peak incidence occurs in those aged over 60 years. It is rare in young adults and in darker-skinned patients. Males are twice as often affected as females.

Clinicals - Examination

Fact Explanation
Papule The initial lesion is a firm, symmetrically round/ dome-shaped papule. The lesion is usually solitary. And the surface is skin colored or inflamed (reddish). Common sites include Neck Face, and dorsum of the upper extremities. Papule
The initial lesion is a firm, symmetrically round/ dome-shaped papule. The lesion is usually solitary. And the surface is skin colored or inflamed (reddish). Common sites include Neck Face, and dorsum of the upper extremities.
Nodule The initial papule rapidly develops in to a dome-shaped nodules with a smooth shiny surface. Nodule
The initial papule rapidly develops in to a dome-shaped nodules with a smooth shiny surface.
Ulcer In later presentation, ulcer can be observed. It enlarges up to 2cm in diameter. The middle of the nodule become ulcerated like a crated. Or a keratin plug appears that may develop into a horn like structure. Ulcer
In later presentation, ulcer can be observed. It enlarges up to 2cm in diameter. The middle of the nodule become ulcerated like a crated. Or a keratin plug appears that may develop into a horn like structure.

Investigations - Diagnosis

Fact Explanation
Histopathology Specimen should be taken as excisional or deep incisional biopsy. Shave biopsy does not help to distinguish keratoacanthoma from invasive squamous cell carcinoma. There is a central plug of keratin producing an invagination of the epidermis. There is a collarette of epidermis at the lateral margin. The epithelium is proliferative but well differentiated, often with a ground glass appearance and marked keratinization. Thus the epithelium exhibiting pseudo-carcinomatous growth pattern. Connective tissue shows a moderate to marked infiltrate of chronic inflammatory cells. Histopathology
Specimen should be taken as excisional or deep incisional biopsy. Shave biopsy does not help to distinguish keratoacanthoma from invasive squamous cell carcinoma. There is a central plug of keratin producing an invagination of the epidermis. There is a collarette of epidermis at the lateral margin. The epithelium is proliferative but well differentiated, often with a ground glass appearance and marked keratinization. Thus the epithelium exhibiting pseudo-carcinomatous growth pattern. Connective tissue shows a moderate to marked infiltrate of chronic inflammatory cells.

Management - Specific

Fact Explanation
Retinoids Though the definitive management of the condition, medical therapy is reserved for multiple lesions and ones which are not amenable to surgery owing to their size or location.
Systemic retinoids, such as isotretinoin, are considered in such instances.
Retinoids
Though the definitive management of the condition, medical therapy is reserved for multiple lesions and ones which are not amenable to surgery owing to their size or location.
Systemic retinoids, such as isotretinoin, are considered in such instances.
Cryotherapy Small keratoacanthomas and lesions in difficult to treat locations are successfully treated with cryotherapy. Cryotherapy
Small keratoacanthomas and lesions in difficult to treat locations are successfully treated with cryotherapy.
Curettage On the trunk, arms, and legs, electrodesiccation and curettage often suffice. Curettage
On the trunk, arms, and legs, electrodesiccation and curettage often suffice.
Excision Excision of the entire lesion is often required if one wants to confirm the clinical diagnosis of keratoacanthoma. Excision
Excision of the entire lesion is often required if one wants to confirm the clinical diagnosis of keratoacanthoma.
Radiotherapy The lesions are radiosensitive and well respond to low doses of radiation.
This may be useful in selected patients with large tumors while resection will result in cosmetic deformity and for tumor's that have recurred following attempted excision.
Radiotherapy
The lesions are radiosensitive and well respond to low doses of radiation.
This may be useful in selected patients with large tumors while resection will result in cosmetic deformity and for tumor's that have recurred following attempted excision.

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