Multiple keratoacanthomas: report of four cases

Clinico-histopathologic and outcome features of cutaneous infundibular keratinizing acanthoma: a case report and literature review

The infundibular keratinizing acanthoma (IKA) is a rare epithelial benign keratin-containing neoplasm of hair follicles. The purpose of this study was to evaluate the defining histopathologic architecture of IKA. A typical IKA consisted of a keratin-filled crypt in the dermis and subcutis that opened to the skin surface. Most of this tumor occurred on the back, neck, head, and the shoulders. Microscopically, the dermal nodules were focally contiguous in both the dermis and subcutis. Furthermore, most histological lesions are consistent with a simple or multiloculated cyst filled with keratin and lined by a wall of stratified squamous epithelium; keratin appears as a concentric lamellar mass, with a keratotic pearly aspect. Histological examination of the cutaneous lesions revealed that the growths were comprised of IKA. IKA of man and dog were compared, and it was concluded that although they are similar in many respects, they are not identical entities. To the best of our knowledge, this is the first report on the prevalence of IKAs among the population of owned dogs in Iran.

Keratoacanthoma: facts and controversies

The keratoacanthoma and its variants are clinically and histologically heterogenous. Some consider the keratoacanthoma to be benign, whereas others classify it as a subtype of squamous cell carcinoma. The keratoacanthoma is generally treated rather than observed for spontaneous resolution. This hampers evaluation of the true natural history of lesions diagnosed as keratoacanthoma. In addition, studies have not found a reliable marker to differentiate keratoacanthoma from squamous cell carcinoma. It currently remains unclear how the keratoacanthoma relates to squamous cell carcinoma, and continued investigation is necessary.

Eruptive keratoacanthoma en plaque in an immunosuppressed patient

Immunosuppressive therapy predisposes to the development of a variety of neoplasms. A 63-year-old man developed multiple eruptive epithelial tumors 15 years after renal transplantation. The tumors included what had been diagnosed as squamous cell carcinomas, Bowen's disease, and solitary and eruptive keratoacanthomas. In addition, he developed a large plaque studded with small nodules that had the histologic features of keratoacanthoma. To our knowledge, this is the first example of acquired eruptive keratoacanthoma forming a large plaque.

Generalized eruptive keratoacanthoma

Two forms of keratoacanthoma are presently recognized: a solitary form and a multiple form. The multiple form has two variants: multiple self-healing epitheliomas of skin or Ferguson Smith type and eruptive keratoacanthoma or Grzybowski type. Though solitary cutaneous keratoacanthomas are common, the multiple variants are extremely rare. A case of eruptive keratoacanthoma with oral involvement is presented with a brief discussion contrasting the two variants of multiple keratoacanthoma.