PHOTO ROUNDS

B ECOME Amel Karaa, MD Tumor with central crusting Department of Internal Medicine,

Mount Auburn Hospital In just 6 weeks, a small, hard papule on the left cheek had Cambridge, Mass Amor Khachemoune, MD, become a prominent 2.1 x 1.8 cm well-circumscribed tumor CWS Ronald O. Perelman Department of , New York University School 63-year-old man came into our was fi rm in texture, but tender to palpa- of Medicine, New York dermatologic clinic with tion and pressure. No lymphadenopathy [email protected] a growth on his left cheek just was present. A EDITOR FIGURE anterior to his sideburn ( ). Our The patient had a history of exten- Richard P. Usatine, MD patient indicated that the lesion, which sive sun exposure, and he’d had previous University of Texas Health appeared 6 weeks earlier, started as a nonmelanoma skin cancers treated with Science Center at San Antonio small, hard papule with a central depres-® Dowdenvarious medical Health and surgical Media techniques. sion and rapidly grew to reach its current The rest of his history and exam were size and shape. within normal limits. We performed a bi- The patient’s face Copyrightwas sun damaged,For personalopsy to confi rm use our clinicalonly diagnosis. and he had a prominent 2.1 × 1.8 cm well-circumscribed, skin-colored tumor on his cheek. The tumor had a central de- ❚ What is your diagnosis? pression covered by a crust that appeared FAST TRACK to conceal a deep keratinous plug. The ❚ How would you manage The tumor had a tumor also had a volcano-like shape and this condition? volcano-like shape FIGURE and was fi rm in Rapidly growing skin-colored tumor texture, but tender to palpation MD KHACHEMOUNE, AMOR BY This 63-year-old man had sun-damaged skin and a prominent 2.1 x 1.8 cm tumor on his left

PHOTO cheek. The tumor had a central crust, which seemed to conceal a deep keratinous plug.

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669_JFP1008 669 9/18/08 10:55:07 AM ROUNDS ❚ Diagnosis: tive, mature, and involution stage. Solitary In the proliferative stage, there is a Our patient had a solitary keratoacan- rapid increase in tumor size; the tumor PHOTO thoma, a unique epidermal tumor that’s can get as big as 10 to 25 mm in diameter characterized by rapid, abundant growth in 6 to 8 weeks.1,7 and spontaneous resolution. This tumor In the mature stage, the tumor stops goes by many names—molluscum seba- growing and maintains a typical vol- ceum, molluscum pseudocarcinomato- cano-like form with a central - sum, cutaneous sebaceous neoplasm, and fi lled crater. self-healing squamous epithelioma—but In the involution stage, up to 50% of keratoacanthoma is the preferred term.1,2 undergo spontaneous There are several types of keratoac- resolution with expulsion of the keratin anthoma, but solitary keratoacanthoma plug and resorption of the tumoral mass. remains the most common. It is typically The process lasts 4 to 6 weeks, on aver- found in light-skinned people in hair-bear- age, but may take up to 1 year. What’s ing, sun-exposed areas. Peak incidence left behind is a residual atrophic and hy- occurs between the ages of 50 and 69, al- popigmented scar.8 though the tumors have been reported in Some lesions persist for a year or patients of all ages. Both sexes are about more, although the entire process from equally affected, although there is a slight start to spontaneous resolution usually predilection for males. Keratoacanthomas takes about 4 to 9 months.2,7,8 mainly develop on the face (lower lip, cheek, nose, and eyelid), neck, and hands. The tumors are often considered be- ❚ Is it an SCC or nign, but they become aggressive in 20% keratoacanthoma? of cases-—showing signs of perineural, Histology is the gold standard in diag- perivascular, and intravascular invasion nosing a keratoacanthoma. A deep bi- and metastases to regional lymph nodes. opsy specimen that preferably includes FAST TRACK As a result, some clinicians consider kera- part or full subcutaneous fat with exci- Although toacanthoma to be a pseudomalignancy sion of the entire lesion should allow with self-regressing potential, while oth- for good histologic interpretation and keratoacanthomas ers view it as a pseudo-benign tumor pro- diagnosis. Keratoacanthoma presents are often gressing into an invasive squamous cell as a downgrowth of well-differentiated considered benign, (SCC).1,2 squamous epithelium. However, even they can become The exact etiology of keratoacanthoma with a well-performed biopsy, the di- is unknown. However, several precipitat- agnosis of keratoacanthoma remains aggressive ing factors have been implicated. Primary challenging due to the lack of suffi - in 20% of cases among them is exposure to cient sensitive or specifi c histological light. Other etiological factors include:3-6 features that can distinguish between • chemical (tar, pitch, keratoacanthomas and SCCs. mineral oil, and cigarette smoking) As a rule, a normal surface epithe- • trauma (body peel, lium surrounding the keratin plug with laser resurfacing, megavoltage ra- sharp demarcation between tumor diation therapy, and ) and stroma favors keratoacanthoma, • whereas ulceration, numerous mitoses, • surgical scar and marked pleomorphism/anaplasia • human papilloma virus (HPV). favor SCC. Because of the lack of a universal diagnostic criterion, several experts recommend that all kerato- ❚ A tumor with 3 stages acanthomas be considered potential Keratoacanthoma undergoes a prolifera- SCCs and thus treated as such.1,2

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❚ When in doubt, cut it out Correspondence Amor Khachemoune, MD, CWS, Assistant Professor, Although the natural course of a kera- Ronald O. Perelman Department of Dermatology, New toacanthoma is spontaneous regression, York University School of Medicine, 530 First Avenue, Suite 7R, New York, NY 10016; [email protected]. the lack of reliable criteria to differenti- ate it from an SCC with confi dence ren- Disclosure The authors reported no potential confl ict of interest rel- ders therapeutic intervention the safest evant to this article. approach. Solitary keratoacanthomas re- References spond well to surgical excision and may 1. Beham A, Regauer S, Soyer HP, Beham-Schmid require aggressive procedures if they be- C. Keratoacanthoma: a clinically distinct variant of well differentiated . Adv come too large or invade other structures. Anat Pathol. 1998;5:269-280. Since Mohs’ micrographic surgery is tis- 2. Schwartz RA. Keratoacanthoma: a clinico-patho- sue sparing, consider it the treatment of logic enigma. Dermatol Surg. 2004;30(2 Pt 2):326- 333; discussion 333. choice if the keratoacanthoma is located 3. Miot HA, Miot LD, da Costa AL, Matsuo CY, Stolf in a sensitive area, such as the face. HO, Marques ME. Association between solitary keratoacanthoma and cigarette smoking: a case- with liquid , control study. Dermatol Online J. 2006;12(2):2. electrodessication and curettage, radia- 4. Pattee SF, Silvis NG. Keratoacanthoma developing in sites of previous trauma: a report of two cases tion therapy, and CO2 laser surgery have and review of the literature. J Am Acad Dermatol. all been used in small solitary keratoac- 2003;48(2 suppl):S35-S38. anthomas with good success.9,10 Other 5. Goldberg LH, Silapunt S, Beyrau KK, Peterson SR, Friedman PM, Alam M. Keratoacanthoma as treatment options include intralesional a postoperative complication of exci- and/or topical treatment using several sion. J Am Acad Dermatol. 2004;50:753-758. 6. Stockfl eth E, Meinke B, Arndt R, Christophers E, compounds, such as 5-fl uorouracil, corti- Meyer T. Identifi cation of DNA sequences of both costeroids, bleomycin, imiquimod, inter- genital and cutaneous HPV types in a small number 7, 9-13 of keratoacanthomas of nonimmunosuppressed feron alpha 2b, and methotrexate. patients. Dermatology. 1999;198:122-125. Keratoacanthoma patients are often 7. Oh CK, Son HS, Lee JB, Jang HS, Kwon KS. In- tralesional interferon alfa-2b treatment of keratoac- UV light sensitive, so they must avoid ex- anthomas. J Am Acad Dermatol. 2004;51(5 suppl): cessive sun exposure and use sunscreen S177-S180. with high SPF at all times to prevent re- 8. Griffi ths RW. Keratoacanthoma observed. Br J Plast Surg. 2004;57:485-501. currence and minimize scarring. 9. Caccialanza M, Sopelana N. of FAST TRACK keratoacanthomas: results in 55 patients. Int J Ra- diat Oncol Biol Phys. 1989;16:475-477. Solitary 10. Gray RJ, Meland NB. Topical 5-fl uorouracil as pri- keratoacanthomas ❚ We opted for Mohs’ mary therapy for keratoacanthoma. Ann Plast Surg. surgery for our patient 2000;44:82-85. respond well to 11. Sanders S, Busam KJ, Halpern AC, Nehal KS. Given the cosmetically sensitive location Intralesional corticosteroid treatment of multiple surgical excision of our patient’s keratoacanthoma, the eruptive keratoacanthomas: case report and re- view of a controversial therapy. Dermatol Surg and may require size of it, and the patient’s history of skin 2002;28:954-958. cancers, we decided to use Mohs’ micro- 12. Di Lernia V, Ricci C, Albertini G. Spontaneous re- aggressive gression of keratoacanthoma can be promoted graphic surgery for the management of by topical treatment with imiquimod cream. J Eur procedures this tumor, with good clinical outcome. Acad Dermatol Venereol. 2004;18:626-629. if they become There were no new lesions or recurrence 13. Cohen PR, Schulze KE, Teller CF, Nelson BR. Intra- lesional methotrexate for keratoacanthoma of the too large on follow-up visit 6 months later. ■ nose. Skinmed. 2005;4:393-395.

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