Know the differences between melanoma, basal cell carcinoma, and squamous cell carcinoma
Know the differences between melanoma, basal cell carcinoma, and squamous cell carcinoma: Excerpt from Avoiding Common Pediatric Errors
Author:
Elizabeth Wells, MD
What to Do - Interpret the Data
Cliniciansoftenhavealowindexofsuspicionformalignantcutaneouslesions
in children, which can lead to a delay in diagnosis and treatment. Below is a
review of the three most common types of skin cancer, including diagnostic
features, management, and important distinctions.
Melanoma
Melanoma is a life-threatening malignant neoplasm of melanocytes, the cells
thatsynthesizeanddepositthepigmentmelanin.Theincidenceofcutaneous
melanoma has been increasing more rapidly than that of any other neoplasm,
and studies suggest that the rates are rising in children. Although only 2% of
all cases occur in pediatric patients, melanomas account for just 5% to 10%
of cutaneous malignant neoplasms in prepubescent children. Pediatricians
must be aware of the potential for melanoma in children, in order to look for
and recognize the lesions early in their progression, when they still may be
curable by surgical resection.
The American Academy of Dermatology has adopted the ABCD criteria for morphologic characteristics of a melanoma: asymmetry, border
irregularity, color variegation, and diameter >6 mm. Childhood melanoma
may also appear atypically with ulceration or a lack of pigment (amelanotic). Dermatologists advise clinicians and patients to be suspicious of the
"ugly duckling"—a lesion that stands out from all the others through differences in color, growth characteristics, or associated signs or symptoms.
Risk factors for melanoma include a history of congenital nevi, dysplastic
nevi, xeroderma pigmentosum, and immunodeficiency states. It is not clear
if light skin, hair, eyes, and history of blistering sunburn confer the same
increased risk in children that they do in adults.
Primary care pediatricians have the opportunity to observe the growth
of benign nevi in their patients over time. Any melanocytic lesion with a
substantial, unexpected change, such as rapid asymmetric growth, crusting,
ulceration, and color loss, warrants a dermatologic evaluation and, possibly,
removal. A skin biopsy is required for any cutaneous lesion that is suspected
of being a melanoma. For smaller lesions, an excisional biopsy that includes
a small (5 mm) margin of normal skin is recommended; incisional biopsies
are performed for very large lesions. All pigmented lesions that are removed
should be submitted for examination by a dermopathologist, particularly as
diagnosis byhistology maybemoredifficultin children thanin adults. When
a diagnosis of primary melanoma is confirmed histologically, re-excision,
with margins of >1 cm, is required.
The prognosis of cutaneous melanoma depends on the Breslow depth
of penetration, which is a measure of lesion thickness in millimeters. Deeper
lesions have a higher risk of local and systemic recurrence. Survival rates are
highformelanomaswithaBreslowdepthof<0.75mmbutdropprecipitously
with a lesion with deep invasion or metastatic spread. Staging of the lesion
is based on adult recommendations and is performed by a careful palpation
of the associated draining lymph nodes and the radiologic examination of
the lung and liver. A sentinel lymph node biopsy is being used more often to
guide management. As there are few studies of chemotherapy in children, a
multidisciplinaryapproachtomelanomatreatmentisrecommendedwithoncologists, dermatologists, surgeons, and others who specialize in pigmented
lesions.
Basal Cell Carcinoma
Basalcellcarcinoma(BCC)isthemostcommonskincancerinadults,andthe
incidence is increasing. The condition peaks in the seventh decade of life and
is rareinchildren.Whenfound in the pediatricagegroup,itisusuallyassociated with a genetic defect, exposure to high-dose radiotherapy, or scars from
a burn or trauma. Although BCC in younger people does not correspond
directly with cumulative sun damage, de novo cases may be more common
in areas of intense ultraviolet (UV) radiation exposure, such as the southwestern United States. BCC presents as a pink, pearly, telangiectatic smooth
papule that enlarges slowly and may ulcerate. It appears most frequently
on the head, neck, and upper extremities, with the majority occurring on
the face. There have been a few cases of BCC on the eyelids of children.
Management of BCC is usually curative and involves electrodessication and
curettage (ED&C),simpleexcision,orMohsmicrosurgery (MMS). The advantages of ED&C are that treatment requires minimal time and equipment
and no suturing; however, there is no histologic examination of tissue with
this method, the site takes a longer time to heal, and the procedure results
in a large hypopigmented patch scar rather than the linear scar that results
from excisional methods. ED&C is most commonly used on superficial BCC
of the trunk or extremities. MMS is indicated when the tumor is recurrent,
>2 cm in diameter, located on problematic anatomic areas, or an aggressive histopathologic type (e.g., morpheaform). The recurrence rate for BCC
treated by MMS is approximately 1%, whereas that for standard excision
is 5% to 10%, depending on the margins of the excision. Cryotherapy is
reserved as second line for patients who cannot tolerate other procedures,
and radiation therapy is no longer recommended. Imiquimod (Aldara) is a
biologic response modifier that stimulates local cytokine release and T cells,
which shows some promise for treating BCC, but has not yet been studied
for this use in children.
In contrast to melanomas, BCCs grow slowly, invade locally, and rarely
metastasize. Early recognition permits treatment of smaller tumors and can
prevent extensive tissue destruction and scarring after excision. Because of
the high association with a positive family history of particular syndromes,
the discovery of a BCC should prompt inquiry into possible systemic associations, such as basal cell nevus syndrome, xeroderma pigmentosum, and
nevus sebaceous.
Squamous Cell Carcinoma
Squamous cell carcinoma (SCC) is the second most common skin cancer.
Unlike BCC, SCC does have the potential to metastasize, especially to regional lymph nodes. Cumulative exposure to UV light appears to be more
important in the pathogenesis of SCC than of BCC. Other risk factors for
SCC include age, immunosuppression, ionizing radiation, environmental
carcinogens, scars, chronic heat exposure or burns, genetic abnormalities
(e.g., mutations in the p53 tumor-suppressor gene), and human papilloma
virus (HPV).
SCC has a predilection for sun-exposed and sun-damaged regions of
the body but can occur anywhere, including mucous membranes. The SCC
lesion appears as a hyperkeratotic, crusted, erythematous nodule or plaque
that may be friable on the surface and is often tender to palpation. Histologically, SCC may be classified into several types, including in situ, well-
differentiated, poorly differentiated, keratoacanthoma, infiltrative, and verrucous carcinoma.
Treatment of SCC is fairly standardized. Cryotherapy, 5-fluorouracil
creams, and ED&C are recommended only for in situ SCC. Otherwise,
treatment is surgical. There are no published guidelines or randomized control studies to delineate treatment for children. For standard excisions in
adults, a 4 mm margin is recommended for tumors of <1 cm in diameter
and <2 mm in depth. For tumors >1 cm in diameter, >6 mm depth, or
more aggressive tumors, 5-mm to 10-mm margins or Mohs microsurgery
(MMS) is recommended. As with BCC, MMS is the method of choice for
treatment of SCC of the head and neck; in immunosuppressed patients; and
for tumors that are recurrent, perineural, >2 cm, incompletely excised, or
histologically aggressive. Radiation is typically used as adjuvant treatment
after the resection of aggressive tumors. SCC is usually more aggressive and
prone to metastasis than BCC.
Pediatricians must be hypervigilant about skin lesions and refer patients
to an experienced pediatric dermatologist, surgeon, or plastic surgeon, keeping in mind that skin cancer is often curable when recognized, diagnosed,
and removed early. To gather more information about staging and therapies
in children, practicing physicians are encouraged to enroll their patients in
cooperative group trials.In addition, pediatricians should educateall parents
and children about the deleterious effects of UV light and make recommendations for sunscreen and protective behavior to help decrease the incidence
of these cutaneous malignancies.
Suggested Readings
Al-Buloushi A, Filho JP, Cassie A, et al. Basal cell carcinoma of the eyelid in children: a report
of three cases. Eye. 2005;19:1313–1314.
Butter A, Hui T, Chapdelaine J, et al. Melanoma in children and the use of sentinel lymph node
biopsy. J Pediatr Surg. 2005;40(5):797–800.
Ferrari A, Bono A, Baldi M, et al. Does melanoma behave differently in younger children than
in adults? A retrospective study of 33 cases of childhood melanoma from a single institution.
Pediatrics. 2005;115:649–654.
Euvrard S, Kanitakis J, Cochat P, et al. Skin cancers following pediatric organ transplantation.
Dermatol Surg. 2004;30(4 Pt 2):616–621.
Lee PK. Common skin cancers. Minn Med. 2004;87(3):44–47.
Leman JA, Evans A, Mooi W, et al. Outcomes and pathological review of a cohort of children
with melanoma. Br J Dermatol. 2005;152:1321–1323.
LeSueur BW, Silvis NG, Hansen RC. Basal cell carcinoma in children: report of 3 cases. Arch
Dermatol. 2000;136(3):370–372.
Mancini AJ. Malignant melanoma in children not as rare as once thought. AAP News.
2005;26(12):14.
Orlow SJ. Melanomas in children. Pediatr Rev. 1995;16(10):365–369.
Pappo AS. Melanoma in children and adolescents. Eur J Cancer. 2003;39(18):2651–2661.
VaranA,GöközA,AkyüzC,etal.Primarymalignantskintumorsinchildren:etiology,treatment
and prognosis. Pediatr Int. 2005;47(6):653–657.
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Book Source Details
- Book Title: Avoiding Common Pediatric Errors
- Author(s): Anthony D Slonim MD, DrPH; Lisa Marcucci MD
- Year of Publication: 2008
- Copyright Details: Avoiding Common Pediatric Errors, Copyright © 2008 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Avoiding Common Pediatric Errors
Authors: Anthony D Slonim MD, DrPH; Lisa Marcucci MD
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7489-6
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