Radiation therapy of keratoacanthoma

Periocular keratoacanthoma: clinical features, pathology, and management

PURPOSE

To review the clinical features and results of surgical treatment of keratoacanthoma of the eyelids.

DESIGN

Retrospective, interventional case series.

PARTICIPANTS

Ten patients.

METHODS

Chart review of all eyelid keratoacanthomas treated between 1992 and 2001.

MAIN OUTCOME MEASURES

Adequate excision, recurrence rate, and complications.

RESULTS

Patient ages ranged from 27 to 78 years, with a mean age of 59 years. Six patients were male and four were female. The lesion was found on the lower lid in five patients, upper lid in two, medial canthus in two, and lateral canthus in one. The maximum diameter of the lesion varied from 2 to 25 mm, with a mean of 7.2 mm. All lesions were treated by surgical excision, with frozen-section control of margins in five cases. All lesions were excised completely with clear resection margins, and there were no cases of recurrence. The only complication was a minor wound infection in one patient. Mean follow-up was 34.5 months.

CONCLUSIONS

Because of the aggressive nature and uncertain relationship to squamous cell carcinoma, we recommend excision of periocular keratoacanthoma. Surgical excision of eyelid keratoacanthoma provides good results and a very low risk of recurrence. Frozen-section control of margins should be used in selected cases to ensure complete excision.

Radiotherapy in the treatment of dermatologic malignancies

Although advances in surgical techniques, particularly micrographic surgery, have considerably expanded its role in the management of dermatologic malignancies, radiotherapy remains of considerable value. Its use should be considered in particular for the appropriate solid tumors in older patients, for metastatic disease, and for the more radioresponsive tumors including Merkel cell carcinoma, Kaposi's sarcoma, and the cutaneous lymphomas.

Giant keratoacanthoma of the lower lip. Report of a case of spontaneous regression

The case of a 46-year-old man who refused treatment of a giant keratoacanthoma of the lower lip is presented. Complete regression took place within 10 months. The dilemma of a lesion of the vermilion border of the lower lip being either a (giant) keratoacanthoma or a squamous cell carcinoma is discussed with respect to the management of such lesions.

Treatment of a recurrent keratoacanthoma with oral isotretinoin

BACKGROUND

Keratoacanthoma is a benign epithelial tumor that occurs on the sun-exposed skin of elderly people. Development of KAS on functionally and cosmetically important areas such as the face poses the therapeutic challenge to minimize functional and cosmetic damage. Oral isotretinoin (Accutane, Roche Laboratories) has been reported to be an effective treatment of multiple as well as solitary keratoacanthomas.

CASE REPORT

A 45-year-old man with a large keratoacanthoma on the nasal ala, recurrent after surgical excision, was treated with 1 mg/kg/day (80 mg/day) oral isotretinoin (Accutane). Cessation of tumor progression was evident within 1 week after initiation of therapy, and tumor regression was evident within 2 weeks. Tumor size diminished rapidly over the ensuing weeks and complete resolution at 12 weeks was confirmed by biopsy.

CONCLUSION

An initial trial of oral isotretinoin is an alternative to immediate surgical excision for the treatment of large keratoacanthomas in instances when tumor removal would cause considerable cosmetic deformity.

Ionizing radiation therapy in dermatology

The introduction of new surgical techniques and other therapeutic modalities has markedly influenced the use of ionizing radiation therapy in dermatology. X-rays and electron beams are now used only for a limited number of indications in carefully selected patients. Since surgical approaches have gained popularity in the treatment of skin tumors, not all dermatologists are familiar with the benefits of ionizing radiation for patients with cutaneous neoplasms and certain other skin disorders. This article reviews modern indications for radiation therapy in dermatology. Important physical and biologic factors, radiation side effects, radiation protection measures, and therapeutic results will also be discussed. Although the use of radiotherapy in dermatology has in large part been supplanted in recent years by other forms of treatment, ionizing radiation continues to be an essential therapeutic alternative for many cutaneous tumors and some skin diseases. It is important to be familiar with the principles of radiotherapy so that optimal therapy can be selected for individual patients.

Keratoacanthoma

The keratoacanthoma is a common cutaneous neoplasm that most often occurs on sun-exposed sites in light-skinned persons of middle age or older. It is considered the prototype of cutaneous pseudo-malignancies because it is a rapidly growing tumor with a histologic pattern resembling squamous cell carcinoma. It may be best viewed as an aborted malignancy that only rarely progresses into an invasive squamous cell carcinoma. It is most likely derived from hair follicle cells. The common type of keratoacanthoma and its many variants are discussed with emphasis on clinical and histologic features, biologic behavior, and response to therapy.

Large keratoacanthomas treated with intralesional interferon alfa-2a

BACKGROUND

Spontaneous involution of giant keratoacanthomas (KAs) can leave large scars or cause mutilation. Human papillomaviruses have recently been demonstrated in KAs. Intralesional interferon alfa-2a (IFN alfa-2a) has been shown to have activity against different epithelial tumors and to have an antiviral effect.

OBJECTIVE

This study was conducted to determine whether it was possible to stop extension of large KAs, to accelerate healing, and to obtain good cosmetic results with intralesional IFN alfa-2a.

METHODS

Six large KAs were treated with intralesional IFN alfa-2a.

RESULTS

Regression was obtained in five cases in 3 to 7 weeks with excellent cosmetic results. The main side effect was pain during injection.

CONCLUSION

Our results suggest that this treatment hastens healing and limits scarring.

Treatment of keratoacanthomas with intralesional methotrexate

Multiple modalities exist for the treatment of keratoacanthoma. Excisional surgery is currently the treatment of choice for the majority of keratoacanthomas. This can result in functional and cosmetic defects when large or strategically located lesions are treated. An effective nonsurgical treatment would be desirable in such cases. Intralesional therapy, particularly with 5-fluorouracil, has been shown to be effective in the treatment of keratoacanthomas. Systemic methotrexate has been tried, with variable success. We report an open, noncontrolled study of nine consecutive patients with unusually large or strategically located solitary keratoacanthomas treated successfully with intralesional methotrexate. All lesions responded promptly, with complete resolution after a mean of 3.0 weeks and a mean of 1.7 injections. No side effects occurred, and scarring was minimal. We concluded that intralesional methotrexate is a simple and effective modality for the treatment of select keratoacanthomas and may offer greater efficacy, a more rapid response, decreased pain, and lower cost compared with intralesional 5-fluorouracil.

Treatment of non-melanoma skin cancer: a review of recent trends with special reference to the Australian scene

Non-melanoma skin cancer (NMSC) is rarely recorded in cancer registries and it is only relatively recently that the serious public health implications, especially in terms of morbidity and expense, have been appreciated. Increased recreational sun exposure (particularly among the young) and ozone layer depletion have generated concern in many countries. Histological confirmation of the diagnosis, either by excision biopsy or punch biopsy is essential if management of the condition is to be rational and the results assessed. Surgery or radiotherapy or other dermatological techniques will cure over 90% of all NMSC. Comparison of the results of various modalities is difficult and poorly documented. Local recurrence rates of 2.0% for surgery and 3.7% for superficial X-ray treatment (SXRT), with 96% and 90% 5-year failure-free-survival respectively are reported from the Peter MacCallum Cancer Institute. More comparative trials are required with good cosmetic and late normal tissue damage evaluation. Factors affecting modality choice trends in Australia are discussed, where the role of plastic surgery has considerably expanded. The indications for radiotherapy and its fractionation require clarification, as does the use of moulds and implants. The belief that solar keratoses transform to invasive cancer has been seriously brought into question by recent Australian epidemiological studies. There can, however, be little doubt of the fact that keratoses are markers of cumulative solar damage, which is a well recognised risk factor for development of NMSC. There is a move away from aggressive ablative treatment of keratoses. The management of keratoacanthoma (KA) by observation is the usual practice, although radiotherapy is occasionally used when the lesion is conspicuous and unsightly.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of aggressive keratoacanthomas by radiotherapy

Keratoacanthomas infrequently are treated by radiotherapy. However, keratoacanthomas that are recurrent after surgical excision or whose resection would result in cosmetic deformity may benefit from radiotherapy. Between January 1970 and June 1988, 29 such keratoacanthomas in 18 patients were irradiated. Doses ranged from 3500 cGy in 15 fractions to 5600 cGy in 28 fractions. Measured end points of therapy were (1) initial response, (2) freedom from recurrence, and (3) quality of the subsequent cosmetic appearance (scored as good, fair, or poor). No lesion progressed and all eventually regressed completely. Cosmetic results generally were considered good by both the patient and the referring dermatologist; none of the results was considered poor. Our results demonstrate that radiation is an effective means of treating keratoacanthomas.

Radiation therapy of keratoacanthomas: results in 55 patients

The radiation therapy of keratoacanthomas in fifty-five patients treated between 1976 and 1986 using orthovoltage X rays (contact and soft X ray therapy) is reported. The total dose delivered was 40 Gy by means of twice weekly fractions of 4 Gy each in 52 cases, and 60 Gy by twice weekly fractions of 5 Gy each in 3 cases with notable cellular atypia. In all cases we obtained complete regression of the lesions irradiated within 1 month after the termination of radiotherapy. So far we have not had any recurrences. The cosmetic result was always satisfactory. We should like to point out the association between keratoacanthomas and a second malignancy in two cases. The role of radiotherapy in the treatment of keratoacanthomas is discussed and re-confirmed, in relation to the literature data.

Keratoacanthomas treated with Mohs' micrographic surgery (chemosurgery). A review of forty-three cases

A series of forty-three keratoacanthomas were treated with Mohs' micrographic surgery with the use of the fresh-tissue technic. Of forty-two keratoacanthomas followed from 6 to 24 months, one aggressive keratoacanthoma recurred, yielding an overall recurrence rate of 2.4%. Micrographic surgery is an expedient treatment that allows for complete microscopic examination of the keratoacanthoma, maximum preservation of normal tissue, and a high degree of assurance of cure.

Variation in the lung inhomogeneity correction factor with beam energy. Clinical implications

In order to determine the magnitude of the dosimetry error introduced by failing to correct for increased transmission through lung tissue in treating thoracic malignancies, measurements in a phantom were taken using different field sizes, inhomogeneity thicknesses and photon qualities. The results indicate that the error introduced by neglecting the inhomogeneity correction is greatest at lower photon energies, smaller field sizes and greater thickness of inhomogeneity. Correction factors to account for the lung inhomogeneity were obtained from phantom measurements and were compared with those calculated using the tissue-air ratio and Batho-Young algorithms; correlation coefficients describing the relationship between measured and calculated values exceeded 0.995. The calculated values tended to overestimate the correction factor and differed most from the measured correction factors at lower energies, smaller field sizes, and greater inhomogeneity thicknesses. The importance of these results in clinical radiation therapy is discussed.

Subungual keratoacanthoma

The subungual keratoacanthoma is a benign neoplasm which simulates and must be differentiated from squamous cell carcinoma. Subungual keratoacanthomas are rapidly growing tumors, causing bone destruction which usually heal spontaneously. The lesion most often presents as a painful, enlarging mass in middle-aged Caucasian patients. Radiographic examination demonstrates a lytic cup-shaped erosion of the underlying distal phalanx. It is essential to recognize keratoacanthoma and separate it from squamous cell carcinoma, both for prognostic and therapeutic reasons. We present two cases of proven subungual keratoacanthoma and discuss their radiographic and histologic characteristics, as well as the current treatment alternatives for this entity.