- Email: [email protected]
Keratoacanthoma arising in newly healed burn scars
172
Burns, 1,172-l
74
Keratoacanthoma burn scars
arising in newly healed
William W. Monafo and Corey Bohling The Department of Surgery, St. JohnS Mercy Medical St. Louis University School of Medicine, and the University of Missouri School of Medicine KERATOACANTHOMA is a rapidly enlarging cutaneous lesion which clinically or histologically may be confused with low grade epidermoid cancer (Reed, 1972). Three instances of keratoacanthoma arising in recently epithelized cutaneous thermal burns have been observed.
CASE
REPORTS
Case 1 A 30-year-old Caucasian man sustained intradermal
flash burns of the face and upper limbs covering 10 per cent of his skin. The wounds were treated with dressings saturated in aqueous 0.5 per cent silver nitrate solution; they healed rapidly. After 11 days he was dismissed from the hospital with instructions to apply 1 per cent silver sulfadiazine cream to the few remaining open wounds, which healed within 10 days. Several wound cultures had been sterile. Five weeks after the injury, an enlarging, tender lesion appeared in a burn scar of the inner aspect of the arm. Grossly, the overlying epithelium appeared intact. The clinical diagnosis was ‘subepidermal nodular fibrosis ‘. When it was excised 2 weeks later, the lesion was 7 mm in diameter. Histologically, it was a keratoacanthoma containing a small central keratin plug (Fig. 1). Case 2 A 3%year-old Caucasian man sustained flame burns of the upper limbs, thighs and back that covered 25 per cent of his skin. The topical treatment of his wound was the same as in Case 1. Split-thickness skin grafts were necessary on the forearms and hands Wound cultures grew only a non-pathogenic bacillus and alpha streptococcus in low density. He left the hospital after 1 month. Five months later, a rapidly enlarging, 1.3 cm in diameter lesion appeared over the left scapula, the site of a healed intradermal burn. Clinically as well as histologically, the lesion, which was excised, was a typical keratoacanthoma (Figs. 2, 3).
Center,
Case 3 A 43-year-old Caucasian man sustained flame burns of the arms, back, face and legs covering 32 per cent of his skin. The treatment of his wounds was the same as in Cases 1 and 2. Split-thickness skin grafts were necessary on portions of the hands and legs. Four weeks after the injury, when some of the wounds were still open, a 0.6 cm in diameter pink nodule appeared at the margin of a recently epithelized burn of the inner aspect of the right arm. Although the lesion was not typical, a correct preoperative diagnosis of ‘keratoacanthoma ’ was made, because of the experience with the two other patients.
DISCUSSION It has been known for more than 150 years that
epidermoid or basal-cell cancers can arise in burn scars (Treves and Pack, 1930). Approximately 1.2 per cent of cutaneous cancers originate in burn scars (Castillo and Goldsmith, 1968). Typically, burn scar cancer (Marjolin’s ulcer) occurs after a latent interval of several years, usually in a wound that healed dilatorily due to
Fig. 1.-Case 1. Photomicrograph of an early keratoacanthoma (proliferative stage) showing marked acanthosis with cords and finger-like projections of epidermal cells infiltrating the cutis. (x 10.)
Monafo
and Bohling
: Keratoacanthoma
in Burn Scars
173
Fig. 2.-Case 2. A clinical photograph of the lesion. The surrounding hypertrophic clinically still hyperaemic, is visible. Inset: a cross-section of the excised lesion.
neglect, mistreatment though
a so-called
or repetitive trauma, alacute form of burn scar cancer
(cancer aigu) also has been observed, in which the cancer develops within only a few months or years (Treves and Pack, 1930). ‘Self-healing squamous carcinoma was described in 1934. The term ‘keratoacanthoma ’was coined in 1950 to describe a self-limited, localized growth of well-differentiated squamous cells (Treves and Pack, 1930). The lesion is characterized by rapid growth, a central keratin core, and on occasion, by spontaneous regression, particularly if the keratin core is dislodged. Keratoacanthoma typically occurs on skin chronically exposed to actinic rays; chronic exposure of the skin to pitch or tar may also
Fig. 3.-Case 2. Photomicrograph of a well-developed keratoacanthoma (keratinizing stage) showing keratinous plugging. The epidermis extends lip-like over the sides of the lesion. There is fibrosis but no inflammation in the underlying dermis.
burn scar, which was
result in the occurrence of keratoacanthoma (Ghadially et al., 1963). The cases here reported were observed within a few months of one another. They represent the only recognized instances of keratoacanthoma in a carefully followed series of thermally injured patients that numbers nearly one thousand. The occurrence of this lesion in burn scars is probably uncommon, yet the question poses itself whether some of the previously reported cases of Marjolin’s ulcer, particularly those described before keratoacanthoma was recognized, may actually represent instances of keratoacanthoma. The keratoacanthomas we have observed arose in intradermal burn scars that had epithelized originally within 30 days. They were not on areas normally open to actinic rays. Since the wounds of the patients were continually exposed for several weeks to silver salts, and since silver stains of the lesions indicated the presence of this metal in the epithelium around and in the lesions, the possibility exists that silver or its salts may have had an aetiological role. The point is discussed presently. Although keratoacanthoma may regress if the keratin plug alone is removed, it is preferable to excise such lesions and examine them histologically. For example, squamous-cell carcinoma has been misdiagnosed as keratoacanthoma when incomplete excision failed to show the malignant portion of the lesion. Recently, several instances in which keratoacanthoma apparently metastasized to regional lymph nodes and/or recurred locally after excision have been noted (Iverson and Vistnes, 1973). Such
Burns
174
occurrences re-emphasize the advisability of adequate local excision of lesions suspected to be keratoacanthoma and lend credence to the possibility that some burn scar cancers may actually be or have originated in keratoacanthomas, which may arise soon after intradermal thermal bums have epithelized, during the phase of persistent cellular activity in the scar. This neoplasm may represent a disorder of wound healing intermediate between the hypertrophic burn scar and typical burn scar cancer.
Vol. 1 /No.
2
REFERENCES CAS~ILLOJ. and GOLDSMITH H. S. (1968) Burn scar carcinoma. Cancer 18, 140-142. GHADIALLY F. N., BARTONB. W. and KERRIDGE D. F. (1963) The etiology of keratoacanthoma. Cancer 16,603-611. IVER.WNR. E. and VWNES L. M. (1973) Keratoacanthoma is frequently a dangerous diagnosis. Am. J. Surg. 126, 359-365. REED R. J. (1972) Actinic keratoacanthoma. Arch. Dem. 106, 858-864. TREVES N. and PACKG. T. (1930) The development of cancer in bum scars. Surg. Gynec. Obstet. 6,749-751.
Requesfsfor reprints should be sent to: William W. Monafo, Esq., M.D., Chairman, Center, 615 S. New Ballas Road, St. Louis, Missouri 63141.
Department
of Surgery, St. John’s Mercy Medical
Burns, 1,172-l
74
Keratoacanthoma burn scars
arising in newly healed
William W. Monafo and Corey Bohling The Department of Surgery, St. JohnS Mercy Medical St. Louis University School of Medicine, and the University of Missouri School of Medicine KERATOACANTHOMA is a rapidly enlarging cutaneous lesion which clinically or histologically may be confused with low grade epidermoid cancer (Reed, 1972). Three instances of keratoacanthoma arising in recently epithelized cutaneous thermal burns have been observed.
CASE
REPORTS
Case 1 A 30-year-old Caucasian man sustained intradermal
flash burns of the face and upper limbs covering 10 per cent of his skin. The wounds were treated with dressings saturated in aqueous 0.5 per cent silver nitrate solution; they healed rapidly. After 11 days he was dismissed from the hospital with instructions to apply 1 per cent silver sulfadiazine cream to the few remaining open wounds, which healed within 10 days. Several wound cultures had been sterile. Five weeks after the injury, an enlarging, tender lesion appeared in a burn scar of the inner aspect of the arm. Grossly, the overlying epithelium appeared intact. The clinical diagnosis was ‘subepidermal nodular fibrosis ‘. When it was excised 2 weeks later, the lesion was 7 mm in diameter. Histologically, it was a keratoacanthoma containing a small central keratin plug (Fig. 1). Case 2 A 3%year-old Caucasian man sustained flame burns of the upper limbs, thighs and back that covered 25 per cent of his skin. The topical treatment of his wound was the same as in Case 1. Split-thickness skin grafts were necessary on the forearms and hands Wound cultures grew only a non-pathogenic bacillus and alpha streptococcus in low density. He left the hospital after 1 month. Five months later, a rapidly enlarging, 1.3 cm in diameter lesion appeared over the left scapula, the site of a healed intradermal burn. Clinically as well as histologically, the lesion, which was excised, was a typical keratoacanthoma (Figs. 2, 3).
Center,
Case 3 A 43-year-old Caucasian man sustained flame burns of the arms, back, face and legs covering 32 per cent of his skin. The treatment of his wounds was the same as in Cases 1 and 2. Split-thickness skin grafts were necessary on portions of the hands and legs. Four weeks after the injury, when some of the wounds were still open, a 0.6 cm in diameter pink nodule appeared at the margin of a recently epithelized burn of the inner aspect of the right arm. Although the lesion was not typical, a correct preoperative diagnosis of ‘keratoacanthoma ’ was made, because of the experience with the two other patients.
DISCUSSION It has been known for more than 150 years that
epidermoid or basal-cell cancers can arise in burn scars (Treves and Pack, 1930). Approximately 1.2 per cent of cutaneous cancers originate in burn scars (Castillo and Goldsmith, 1968). Typically, burn scar cancer (Marjolin’s ulcer) occurs after a latent interval of several years, usually in a wound that healed dilatorily due to
Fig. 1.-Case 1. Photomicrograph of an early keratoacanthoma (proliferative stage) showing marked acanthosis with cords and finger-like projections of epidermal cells infiltrating the cutis. (x 10.)
Monafo
and Bohling
: Keratoacanthoma
in Burn Scars
173
Fig. 2.-Case 2. A clinical photograph of the lesion. The surrounding hypertrophic clinically still hyperaemic, is visible. Inset: a cross-section of the excised lesion.
neglect, mistreatment though
a so-called
or repetitive trauma, alacute form of burn scar cancer
(cancer aigu) also has been observed, in which the cancer develops within only a few months or years (Treves and Pack, 1930). ‘Self-healing squamous carcinoma was described in 1934. The term ‘keratoacanthoma ’was coined in 1950 to describe a self-limited, localized growth of well-differentiated squamous cells (Treves and Pack, 1930). The lesion is characterized by rapid growth, a central keratin core, and on occasion, by spontaneous regression, particularly if the keratin core is dislodged. Keratoacanthoma typically occurs on skin chronically exposed to actinic rays; chronic exposure of the skin to pitch or tar may also
Fig. 3.-Case 2. Photomicrograph of a well-developed keratoacanthoma (keratinizing stage) showing keratinous plugging. The epidermis extends lip-like over the sides of the lesion. There is fibrosis but no inflammation in the underlying dermis.
burn scar, which was
result in the occurrence of keratoacanthoma (Ghadially et al., 1963). The cases here reported were observed within a few months of one another. They represent the only recognized instances of keratoacanthoma in a carefully followed series of thermally injured patients that numbers nearly one thousand. The occurrence of this lesion in burn scars is probably uncommon, yet the question poses itself whether some of the previously reported cases of Marjolin’s ulcer, particularly those described before keratoacanthoma was recognized, may actually represent instances of keratoacanthoma. The keratoacanthomas we have observed arose in intradermal burn scars that had epithelized originally within 30 days. They were not on areas normally open to actinic rays. Since the wounds of the patients were continually exposed for several weeks to silver salts, and since silver stains of the lesions indicated the presence of this metal in the epithelium around and in the lesions, the possibility exists that silver or its salts may have had an aetiological role. The point is discussed presently. Although keratoacanthoma may regress if the keratin plug alone is removed, it is preferable to excise such lesions and examine them histologically. For example, squamous-cell carcinoma has been misdiagnosed as keratoacanthoma when incomplete excision failed to show the malignant portion of the lesion. Recently, several instances in which keratoacanthoma apparently metastasized to regional lymph nodes and/or recurred locally after excision have been noted (Iverson and Vistnes, 1973). Such
Burns
174
occurrences re-emphasize the advisability of adequate local excision of lesions suspected to be keratoacanthoma and lend credence to the possibility that some burn scar cancers may actually be or have originated in keratoacanthomas, which may arise soon after intradermal thermal bums have epithelized, during the phase of persistent cellular activity in the scar. This neoplasm may represent a disorder of wound healing intermediate between the hypertrophic burn scar and typical burn scar cancer.
Vol. 1 /No.
2
REFERENCES CAS~ILLOJ. and GOLDSMITH H. S. (1968) Burn scar carcinoma. Cancer 18, 140-142. GHADIALLY F. N., BARTONB. W. and KERRIDGE D. F. (1963) The etiology of keratoacanthoma. Cancer 16,603-611. IVER.WNR. E. and VWNES L. M. (1973) Keratoacanthoma is frequently a dangerous diagnosis. Am. J. Surg. 126, 359-365. REED R. J. (1972) Actinic keratoacanthoma. Arch. Dem. 106, 858-864. TREVES N. and PACKG. T. (1930) The development of cancer in bum scars. Surg. Gynec. Obstet. 6,749-751.
Requesfsfor reprints should be sent to: William W. Monafo, Esq., M.D., Chairman, Center, 615 S. New Ballas Road, St. Louis, Missouri 63141.
Department
of Surgery, St. John’s Mercy Medical