9.2 Cryotherapy and electrodessication and curettage for cutaneous squamous cell carcinoma
Cutaneous squamous cell carcinomas (cSCCs) are very common in Australia and are the second most common skin cancer. Small superficial and well-differentiated cSCCs in low risk sites can be adequately treated with cryotherapy or electrodessication and curettage (EDC).
Relative indications of cryotherapy and EDC for cSCC and related lesions include:
- Bowen’s disease, especially on trunk or limbs
- cSCCs of low-risk type, especially on the trunk and limbs
- the treatment of lesions in elderly patients, especially those with medical disorders less tolerant of surgical procedures (e.g. those with pacemakers or coagulopathies)
- in geographic areas with poor access to surgical facilities
- palliation of inoperable tumours.
Cryotherapy may be appropriate for lesions at body sites with increased risk of keloid scars from other treatment modalities (e.g. curettage or surgical excision on the upper arms and upper trunk).
Relative contraindications of cryotherapy and EDC for cSCC and related lesions include:
- cosmetically sensitive sites, especially face and neck in younger patients
- high-risk body sites, especially on face and neck (i.e. sites where it is difficult to ascertain depth of tumour penetration or where deep recurrence poses greater potential risks)
- high-risk tumour categories (i.e. ill-defined or sclerosing BCC and moderately to poorly differentiated cSCC)
- recurrent cancers for which surgical excision with histological confirmation of clear margins is essential.
With the increasing number of organ transplant patients developing very large numbers of cSCCs, the use of EDC in selected tumours can be of value where surgical excision may be impractical.
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Overview of evidence (non-systematic literature review)[edit source]
Cryotherapy produces cure rates equivalent to other standard treatment modalities for low-risk cSCCs on the trunk and limbs.
Small (<1cm) well-differentiated cSCC in low-risk areas can often be adequately treated with cryotherapy.
Bowen’s disease (cSCC in situ) can be often adequately treated with cryotherapy.
No randomised controlled studies have compared cryotherapy with surgery or other treatment approaches in the treatment of cSCC. Observational studies such as case series have reported outcomes of EDC in the treatment of cSCC.[references]]
Cryotherapy for cutaneous squamous cell carcinoma[edit source]
Low-risk cSCCs can be treated by cryosurgery. It may be indicated for small primary well-defined and non-ulcerated tumours on the trunk and limbs, for which acceptable cure rates have been reported. In general, less-well differentiated cSCCs, recurrent cSCCs and those on the head and neck are better treated by surgical excision or radiotherapy.
Histological confirmation and analysis for high-risk features is essential prior to cryosurgery.
Relative to their prevalence, fewer cSCCs are treated by cryotherapy than BCCs, implying that most published studies employ strict selection guidelines.
In general, low-risk tumours are selected. The criteria for such cSCCs include:
- primary tumour
- small size
- well defined
- clinically and histologically well differentiated
- on trunk or limbs.
Repeated freeze–thaw cycles with a minimum of 5mm margins are recommended. Curettage may be used initially to debulk the lesion, followed by cryosurgery.
Cure rates of greater than 95% are consistently achieved if selection criteria are strict and optimal treatment protocols are employed.
Even with strict selection criteria in experienced clinics, there are some recurrences following cryosurgery for head and neck lesions, in contrast to the very rare recurrences for those on the trunk and limbs. Cryosurgical management of SCC on the head and neck should generally be limited to specialist clinics with the full range of treatment options available.
Residual or recurrent SCCs are better removed surgically, or treated with radiotherapy, as cryosurgery leads to unacceptably low cure rates.
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Cryotherapy for actinic keratoses[edit source]
Actinic (solar) keratoses (AKs) are common skin lesions displaying different clinical and histological features. They represent both markers of actinic damage and potential precursors of cSCCs.
A continuum of clinical and histological dysplasia occurs from AK to Bowen’s disease (cSCC in situ ) and invasive cSCC. However, not all AKs progress to SCC and some can regress spontaneously or following routine use of sunscreen application. No clinical feature of AKs predicts which will become malignant. However, increased erythema, thickening, alteration or changes in size may indicate early progression to cSCC. The risk of cSCC may be greater for immunosuppressed patients.
The diagnosis of AK is usually made clinically, but biopsy may be indicated to exclude malignancy.
Actinic keratoses may be treated for cosmetic reasons, due to irritation, or because of the potential for developing cSCC.
Topical 5 Fluorouracil cream may be used initially to highlight subclinical keratoses prior to cryotherapy treatment.
Successful clearance of AKs using cryotherapy with good cosmetic results requires accurate diagnosis and adequately timed treatment protocols. A single freeze–thaw cycle is usually recommended. Cure rates ranging from 69% to greater than 98.8% have been reported. Response rates tend to parallel the duration of the freeze time.
Hyperkeratotic or suspicious AKs may be better treated by curettage alone, or curettage followed by cryotherapy, EDC or ablative laser to the base. These techniques provide a specimen for histological confirmation.
A range of topical therapies can be used to reduce signs of photodamage and to treat established and preclinical actinic keratoses. These include chemical peeling, dermabrasion, laser resurfacing, alpha-hydroxy acids and retinoid formulations, diclofenac 3% in hyaluronic acid 2.5% gel, imiquimod 5% cream, ingenol mebutate, and photodynamic therapy.
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Cryotherapy for Bowen’s disease (cSCC in situ)[edit source]
Bowen’s disease (cSCC in situ) is not invasive and does not need to be treated in the same manner as cSCC. Bowen’s disease has been treated successfully with cryosurgery, with many studies reporting greater than 95% cure rates and reasonable follow-up periods. Suboptimal treatment protocols produce less satisfactory results. A pre-treatment biopsy is usually recommended.
A single freeze-thaw treatment cycle of 30 seconds with a 3mm margin is advised. Slow healing was reported for lesions greater than 20mm in diameter and for those on the lower legs. Cure rates greater than 99% are achieved with optimal cryotherapy consisting of liquid nitrogen used in an open spray technique with a single freeze cycle of 30 seconds or greater, achieving a minimal 3mm freeze halo around the marked lesion. Cure rates vary from 66% to 97% with less aggressive protocols.
Anatomical site does not appear to affect response to cryotherapy.
The size of the lesion does not affect response and large lesions can be managed with overlapping treatment fields.
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Cryotherapy for keratoacanthoma[edit source]
Keratoacanthomas can be treated with cryotherapy, achieving cure rates equivalent to EDC, simple excision or radiotherapy.
Larger lesions are often removed by curettage (providing a specimen for histology) followed by double freeze–thaw cycle cryotherapy to the base of the lesion.
Few studies have investigated outcomes of cryotherapy for keratoacanthomas. A cure rate of 87.5% was achieved in one series of five lesions on the head and neck and three lesions on the trunk and limbs. Double freeze–thaw cycles of 30 seconds or more with 3–5 mm treatment margins were used. Site differences in response to cryotherapy have not been noted in the small series reported. Size appears to have been a factor in the choice of cryotherapy, with almost all treated lesions less than 20mms in diameter. One large keratoacanthoma responded to cryotherapy after initial shave excision.(See: Clinical features of cutaneous squamous cell carcinoma).
Electrodessication and curettage for cSCC[edit source]
There is little evidence to determine the role of EDC in the management of cSCC and there is no international clinical consensus on its use.
No randomised controlled studies have compared EDC with surgery or other treatment approaches in the treatment of cSCC and related lesions. Observational studies such as case series have reported outcomes of EDC in the treatment of cSCC.\
Electrodessication and curettage should only be performed by operators with appropriate supervised training in the procedures.
EDC for cutaneous squamous cell carcinoma[edit source]
One study demonstrated a cure rate of 96% in a group of 48 patients followed for 5 years and 98% in a group of 101 patients observed over 4 years. In both groups selection was based on a lesion size of less than 2cm and ‘unusually invasive, destructive, or sclerosing’ lesions were treated by irradiation or surgery.
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EDC for Bowen’s disease (cSCC in situ)[edit source]
Electrodessication and curettage is one of a number of modalities used by dermatologists in the management of Bowen’s disease on exposed areas. The technique requires that the skin be stabilised by stretching to provide a firm base against which to curette.
It is also important that the dermis does allow the curette to break through to the deeper tissues. This limitation precludes the use of the technique on eyelids, the genital area or lip.
As many cases occur on the legs of elderly patients, this method has the advantage of not requiring reconstruction.
Published data are limited to retrospective, uncontrolled studies with inadequate follow-up. These studies report recurrence rates ranging from 6.25% to 20%.
EDC for keratoacanthoma[edit source]
Keratoacanthoma may be considered a relatively benign tumour and is commonly treated by dermatologists using the EDC technique.
Good cosmetic results have been reported anecdotally. Published studies show acceptable cure rates but are compromised by follow-up times of less than 5 years.
Electrodessication and curettage of keratoacanthoma involving the nail bed is controversial.
Electrodessication and curettage seems an acceptable procedure for keratoacanthoma, provided that:
- it has not been previously treated
- it is not on the ear or lip
- it is less than 1cm in diameter on other parts of the head
- it strictly satisfies the clinical diagnostic criteria for keratoacanthoma
- the curette is used to obtain the largest and deepest single piece of tissue possible for histology and the report is consistent with the diagnosis
- close follow-up can be achieved with immediate excision at the first sign of recurrence
- it is carried out by operators with appropriate supervised training in the procedure.
Electrodessication and curettage is not appropriate for:
- lesions in high-risk areas (nasal, paranasal, lips, eyelids, chin, jawline and ears), or at least not for lesions larger than 5mm at these sites
- lesions larger than 10mm on moderate-risk sites (face, forehead, temples and scalp)
- lesion of any size on low-risk areas (neck, trunk and limbs).
- clinically sclerosing lesions.
- recurrent lesions.
Practice Point[edit source]
PP 9.2.1. Cryotherapy is contraindicated for recurrent cutaneous squamous cell carcinoma.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Silverman MK, Kopf AW, Grin CM, Bart RS, Levenstein MJ. Recurrence rates of treated basal cell carcinomas. Part 2: Curettage-electrodesiccation. J Dermatol Surg Oncol 1991 Sep;17(9):720-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/1820764.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 De Lanza MP, Ralfs I, Dawber RP. Cryosurgery for Bowen's Disease of the skin. Br J Cancer 1980;18:14. 103(18) p14.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Zacarian SA. Cryosurgery of cutaneous carcinomas. An 18-year study of 3,022 patients with 4,228 carcinomas. J Am Acad Dermatol 1983 Dec;9(6):947-56 Available from: http://www.ncbi.nlm.nih.gov/pubmed/6643791.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 Holt PJ. Cryotherapy for skin cancer: results over a 5-year period using liquid nitrogen spray cryosurgery. Br J Dermatol 1988 Aug;119(2):231-40 Available from: http://www.ncbi.nlm.nih.gov/pubmed/3166941.
- ↑ 5.0 5.1 5.2 5.3 Graham GF. Statistical data on malignant tumors in cryosurgery: 1982. J Dermatol Surg Oncol 1983 Mar;9(3):238-9 Available from: http://www.ncbi.nlm.nih.gov/pubmed/6826880.
- ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 Kuflik EG, Gage AA. The five-year cure rate achieved by cryosurgery for skin cancer. J Am Acad Dermatol 1991 Jun;24(6 Pt 1):1002-4 Available from: http://www.ncbi.nlm.nih.gov/pubmed/1820761.
- ↑ 7.0 7.1 7.2 7.3 Graham GF. Cryosurgery. Clin Plast Surg 1993 Jan;20(1):131-47 Available from: http://www.ncbi.nlm.nih.gov/pubmed/8420702.
- ↑ 8.0 8.1 Kingston T, Jackson A, August P. Cryosurgery in the treatment of skin cancer. Br J Cancer 1988;119 (suppl):33-39.
- ↑ 9.0 9.1 9.2 9.3 Nordin P. Curettage-cryosurgery for non-melanoma skin cancer of the external ear: excellent 5-year results. Br J Dermatol 1999 Feb;140(2):291-3 Available from: http://www.ncbi.nlm.nih.gov/pubmed/10233225.
- ↑ 10.0 10.1 Albright SD 3rd. Treatment of skin cancer using multiple modalities. J Am Acad Dermatol 1982 Aug;7(2):143-71 Available from: http://www.ncbi.nlm.nih.gov/pubmed/6752218.
- ↑ Kim JYS, Kozlow JH, Mittal B, Moyer J, Olenecki T, Rodgers P, et al. Guidelines of care for the management of cutaneous squamous cell carcinoma. J Am Acad Dermatol 2018 Mar;78(3):560-578 Available from: http://www.ncbi.nlm.nih.gov/pubmed/29331386.
- ↑ Drake LA, Ceilley RI, Cornelison RL, Dobes WA, Dorner W, Goltz RW, et al. Guidelines of care for basal cell carcinoma. The American Academy of Dermatology Committee on Guidelines of Care. J Am Acad Dermatol 1992 Jan;26(1):117-20 Available from: http://www.ncbi.nlm.nih.gov/pubmed/1732317.
- ↑ 13.0 13.1 13.2 13.3 Kuflik EG. Cryosurgical treatment for large malignancies on the upper extremities. J Dermatol Surg Oncol 1986 Jun;12(6):575-7 Available from: http://www.ncbi.nlm.nih.gov/pubmed/3711418.
- ↑ 14.0 14.1 14.2 14.3 14.4 14.5 14.6 Martins O, Oliveira Ada S, Picoto Ada S, Verde SF. Cryosurgery of large tumors on the dorsa of hands. J Dermatol Surg Oncol 1980 Jul;6(7):568-70 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7391333.
- ↑ Graham G, Garnett A, Kuflik E, Lubritz R. Guidelines of care for cryosurgery. American Academy of Dermatology Committee on Guidelines of Care. J Am Acad Dermatol 1994 Oct [cited 2018 Oct];31(4):648-53 Available from: http://www.ncbi.nlm.nih.gov/pubmed/8089292.
- ↑ 16.0 16.1 Drake LA, Ceilley RI, Cornelison RL, et al. Guidelines of care for cryosurgery. J Am Acad Dermatol 1994 Oct [cited 2018 Oct];31:648-653 Available from: https://www.jaad.org/article/S0190-9622(08)81730-6/pdf.
- ↑ 17.0 17.1 Fraunfelder FT, Zacarian SA, Limmer BL, Wingfield D. Cryosurgery for malignancies of the eyelid. Ophthalmology 1980 Jun;87(6):461-5 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7413134.
- ↑ Lubritz RR. Cryosurgical management of multiple skin carcinomas. J Dermatol Surg Oncol 1977 Jul;3(4):414-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/893762.
- ↑ Kuflik EG. Treatment of basal- and squamous-cell carcinomas on the tip of the nose by cryosurgery. J Dermatol Surg Oncol 1980 Oct;6(10):811-3 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7229166.
- ↑ 20.0 20.1 20.2 Fraunfelder FT, Zacarian SA, Wingfield DL, Limmer BL. Results of cryotherapy for eyelid malignancies. Am J Ophthalmol 1984 Feb;97(2):184-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/6696028.
- ↑ 21.0 21.1 21.2 21.3 21.4 Fraunfelder FT, Farris HE Jr, Wallace TR. Cryosurgery for ocular and periocular lesions. J Dermatol Surg Oncol 1977 Jul;3(4):422-7 Available from: http://www.ncbi.nlm.nih.gov/pubmed/893764.
- ↑ Green A, Battistutta D. Incidence and determinants of skin cancer in a high-risk Australian population. Int J Cancer 1990 Sep 15;46(3):356-61 Available from: http://www.ncbi.nlm.nih.gov/pubmed/2394501.
- ↑ Marks R, Foley P, Goodman G, Hage BH, Selwood TS. Spontaneous remission of solar keratoses: the case for conservative management. Br J Dermatol 1986 Dec;115(6):649-55 Available from: http://www.ncbi.nlm.nih.gov/pubmed/3801305.
- ↑ Thompson SC, Jolley D, Marks R. Reduction of solar keratoses by regular sunscreen use. N Engl J Med 1993 Oct 14;329(16):1147-51 Available from: http://www.ncbi.nlm.nih.gov/pubmed/8377777.
- ↑ Kligman LH, Akin FJ, Kligman AM. Sunscreens promote repair of ultraviolet radiation-induced dermal damage. J Invest Dermatol 1983 Aug;81(2):98-102 Available from: http://www.ncbi.nlm.nih.gov/pubmed/6223959.
- ↑ 26.0 26.1 Drake LA, Ceilley RI, Cornelison RL, Dobes WL, Dorner W, Goltz RW, et al. Guidelines of care for actinic keratoses. Committee on Guidelines of Care. J Am Acad Dermatol 1995 Jan;32(1):95-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7529779.
- ↑ Jensen P, Hansen S, Møller B, Leivestad T, Pfeffer P, Geiran O, et al. Skin cancer in kidney and heart transplant recipients and different long-term immunosuppressive therapy regimens. J Am Acad Dermatol 1999 Feb;40(2 Pt 1):177-86 Available from: http://www.ncbi.nlm.nih.gov/pubmed/10025742.
- ↑ 28.0 28.1 Johnson TM, Rowe DE, Nelson BR, Swanson NA. Squamous cell carcinoma of the skin (excluding lip and oral mucosa). J Am Acad Dermatol 1992 Mar;26(3 Pt 2):467-84 Available from: http://www.ncbi.nlm.nih.gov/pubmed/1564155.
- ↑ Sinclair RD, Dawber RP. Cryosurgery of malignant and premalignant diseases of the skin: a simple approach. Australas J Dermatol 1995 Aug;36(3):133-42 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7487739.
- ↑ Young R, Sinclair R. Practical cryosurgery. Aust Fam Physician 1997 Sep;26(9):1045-7 Available from: http://www.ncbi.nlm.nih.gov/pubmed/9382718.
- ↑ Szeimies RM, Karrer S, Radakovic-Fijan S, Tanew A, Calzavara-Pinton PG, Zane C, et al. Photodynamic therapy using topical methyl 5-aminolevulinate compared with cryotherapy for actinic keratosis: A prospective, randomized study. J Am Acad Dermatol 2002 Aug;47(2):258-62 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12140473.
- ↑ Freeman M, Vinciullo C, Francis D, Spelman L, Nguyen R, Fergin P, et al. A comparison of photodynamic therapy using topical methyl aminolevulinate (Metvix) with single cycle cryotherapy in patients with actinic keratosis: a prospective, randomized study. J Dermatolog Treat 2003 Jun;14(2):99-106 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12775317.
- ↑ Lubritz RR, Smolewski SA. Cryosurgery cure rate of actinic keratoses. J Am Acad Dermatol 1982 Nov;7(5):631-2 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7142470.
- ↑ Thai KE, Fergin P, Freeman M, Vinciullo C, Francis D, Spelman L, et al. A prospective study of the use of cryosurgery for the treatment of actinic keratoses. Int J Dermatol 2004 Sep;43(9):687-92 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15357755.
- ↑ Smith SR, Morhenn VB, Piacquadio DJ. Bilateral comparison of the efficacy and tolerability of 3% diclofenac sodium gel and 5% 5-fluorouracil cream in the treatment of actinic keratoses of the face and scalp. J Drugs Dermatol 2006 Feb;5(2):156-9 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16485883.
- ↑ Korman N, Moy R, Ling M, Matheson R, Smith S, McKane S, et al. Dosing with 5% imiquimod cream 3 times per week for the treatment of actinic keratosis: results of two phase 3, randomized, double-blind, parallel-group, vehicle-controlled trials. Arch Dermatol 2005 Apr;141(4):467-73 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15837864.
- ↑ Pariser DM, Lowe NJ, Stewart DM, Jarratt MT, Lucky AW, Pariser RJ, et al. Photodynamic therapy with topical methyl aminolevulinate for actinic keratosis: results of a prospective randomized multicenter trial. J Am Acad Dermatol 2003 Feb;48(2):227-32 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12582393.
- ↑ 38.0 38.1 Mortimer PS, Sonnex TS, Dawber RP. Cryotherapy for multicentric pigmented Bowen's disease. Clin Exp Dermatol 1983 May;8(3):319-22 Available from: http://www.ncbi.nlm.nih.gov/pubmed/6883799.
- ↑ Rosso S, Zanetti R, Martinez C, Tormo MJ, Schraub S, Sancho-Garnier H, et al. The multicentre south European study 'Helios'. II: Different sun exposure patterns in the aetiology of basal cell and squamous cell carcinomas of the skin. Br J Cancer 1996 Jun;73(11):1447-54 Available from: http://www.ncbi.nlm.nih.gov/pubmed/8645596.
- ↑ Castrow FF, Williams TE. Basal-cell epithelioma occurring in a smallpox vaccination scar. J Dermatol Surg 1976 May;2(2):151-2 Available from: http://www.ncbi.nlm.nih.gov/pubmed/932293.
- ↑ Kricker A, Armstrong BK, English DR, Heenan PJ. Does intermittent sun exposure cause basal cell carcinoma? a case-control study in Western Australia. Int J Cancer 1995 Feb 8;60(4):489-94 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7829262.
- ↑ 42.0 42.1 42.2 Thestrup-Pedersen K, Ravnborg L, Reymann F. Morbus Bowen. A description of the disease in 617 patients. Acta Derm Venereol 1988;68(3):236-9 Available from: http://www.ncbi.nlm.nih.gov/pubmed/2455417.
- ↑ 43.0 43.1 Morton CA, Whitehurst C, Moseley H, McColl JH, Moore JV, Mackie RM. Comparison of photodynamic therapy with cryotherapy in the treatment of Bowen's disease. Br J Dermatol 1996 Nov;135(5):766-71 Available from: http://www.ncbi.nlm.nih.gov/pubmed/8977678.
- ↑ 44.0 44.1 44.2 44.3 Cox NH, Dyson P. Wound healing on the lower leg after radiotherapy or cryotherapy of Bowen's disease and other malignant skin lesions. Br J Dermatol 1995 Jul;133(1):60-5 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7669642.
- ↑ Ball SB, Dawber RP. Treatment of cutaneous Bowen's disease with particular emphasis on the problem of lower leg lesions. Australas J Dermatol 1998 May;39(2):63-8; quiz 69-70 Available from: http://www.ncbi.nlm.nih.gov/pubmed/9611372.
- ↑ Cox NH, Eedy DJ, Morton CA, Therapy Guidelines and Audit Subcommittee, British Association of Dermatologists.. Guidelines for management of Bowen's disease: 2006 update. Br J Dermatol 2007 Jan;156(1):11-21 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17199561.
- ↑ Morton C, Horn M, Leman J, Tack B, Bedane C, Tjioe M, et al. Comparison of topical methyl aminolevulinate photodynamic therapy with cryotherapy or Fluorouracil for treatment of squamous cell carcinoma in situ: Results of a multicenter randomized trial. Arch Dermatol 2006 Jun;142(6):729-35 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16785375.
- ↑ Kuflik EG. Cryosurgery for cutaneous malignancy. An update. Dermatol Surg 1997 Nov;23(11):1081-7 Available from: http://www.ncbi.nlm.nih.gov/pubmed/9391569.
- ↑ Schwartz RA. Keratoacanthoma. J Am Acad Dermatol 1994 Jan;30(1):1-19; quiz 20-2 Available from: http://www.ncbi.nlm.nih.gov/pubmed/8277007.
- ↑ 50.0 50.1 Freeman Rg, Knox Jm, Heaton Cl. The Treatment of Skin Cancer. A Statistical Study of 1,341 Skin Tumors Comparing Results Obtained with Irradiation, Surgery, and Curettage Followed by Electrodesiccation. Cancer 1964 Apr;17:535-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/14136537.
- ↑ Sturm HM. Bowen's disease and 5-fluorouracil. J Am Acad Dermatol 1979 Dec;1(6):513-22 Available from: http://www.ncbi.nlm.nih.gov/pubmed/528700.
- ↑ 52.0 52.1 52.2 Reymann F. Multiple basal cell carcinomas of the skin. Treatment with curettage. Arch Dermatol 1975 Jul;111(7):877-9 Available from: http://www.ncbi.nlm.nih.gov/pubmed/1147632.
- ↑ 53.0 53.1 Nedwich JA. Evaluation of curettage and electrodesiccation in treatment of keratoacanthoma. Australas J Dermatol 1991;32(3):137-41 Available from: http://www.ncbi.nlm.nih.gov/pubmed/1823109.
- ↑ Pellegrini VD Jr, Tompkins A. Management of subungual keratoacanthoma. J Hand Surg Am 1986 Sep;11(5):718-24 Available from: http://www.ncbi.nlm.nih.gov/pubmed/3760501.
- ↑ Keeney GL, Banks PM, Linscheid RL. Subungual keratoacanthoma. Report of a case and review of the literature. Arch Dermatol 1988 Jul;124(7):1074-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/3291779.
- ↑ Emmett AJ. Surgical analysis and biological behaviour of 2277 basal cell carcinomas. Aust N Z J Surg 1990 Nov;60(11):855-63 Available from: http://www.ncbi.nlm.nih.gov/pubmed/2241644.
- ↑ Menn H, Robins P, Kopf AW, Bart RS. The recurrent basal cell epithelioma. A study of 100 cases of recurrent, re-treated basal cell epitheliomas. Arch Dermatol 1971 Jun;103(6):628-31 Available from: http://www.ncbi.nlm.nih.gov/pubmed/5555851.