Key Terms
Spitz Nevus
Atypical Spitz nevus
Atypical Spitzoid tumor
Desmoplastic Spitz nevi
Dermatofibroma
Cutaneous fibrous histiocytoma
Bednar tumor
Papular and nodular neoplasms without scale comprise many important and potentially deadly tumors of the skin. Although this group of lesions is usually without scale, it is important to recognize that any lesion with significant trauma or inflammation may demonstrate some scale. Moreover, the malignant tumors in this group can attain a large size, may become large indurated plaques, or may outgrow a blood supply to become ulcerated. A partial listing of papular and nodular growths is provided in the box.
Important History Questions
How long has this lesion(s) been present?
This is an important question because some of the entities in this group, such as dermatofibroma and intradermal nevus, tend to be stable over time, whereas other serious conditions, such as lymphomas and metastatic tumors, may be of recent onset or have rapid growth. Exceptions to this rule exist, such as dermatofibrosarcoma protuberans (DFSP) and some basal cell carcinomas, which can demonstrate slow progressive growth, despite being malignant.
Has the lesion changed?
This question is pertinent when evaluating whether a neoplasm lesion is benign or malignant. An affirmative answer to this question should result in a reduced threshold for performing a diagnostic biopsy.
Have you or any member of your family had similar lesions or a history of cancer?
The answer to this question could suggest a potential genodermatosis, such as neurofibromatosis type 1 (NF-1). Also, if the patient has a history of malignancy, the differential diagnosis should be expanded to include a potential metastasis, with a reduced threshold for performing a diagnostic biopsy.
Important Physical Findings
How old is the patient?
Some lesions, such as Spitz nevi, are more likely to occur in children or young adolescents, whereas dermatofibroma and neurofibromas are more common in postpubertal adolescents and young adults. Malignant tumors, including metastases, are more likely to occur in older adults.
How many lesions are present?
This is a critical finding because some lesions, like Spitz nevi, keloids, or dermatofibromas, are more likely to be solitary, whereas metastases and neurofibromas in NF-1 are more likely to present as multiple lesions.
What is the distribution of the lesions?
Some papular and nodular lesions have characteristic anatomic locations. For example, syringomas (small benign sweat gland tumors) are frequently located in the periocular or genital areas. Dermatofibromas often occur on the lower extremities of young adults, particularly women who shave their legs. Basal cell carcinoma and Merkel cell carcinoma are more likely to occur on sun-damaged skin.
Are any of the lesions ulcerated or necrotic?
Although trauma can cause ulceration in any exophytic process, benign or malignant, ulceration is more common with malignant processes, such as basal cell carcinoma, Merkel cell carcinoma, and metastatic tumors. Metastases in particular may ulcerate due to growth that outstrips the blood supply.
Basal Cell Carcinoma
ICD10 code C44 (site dependent)
MALIGNANT NEOPLASM
Pathogenesis
Basal cell carcinoma (BCC) is the most common cutaneous malignancy in the United States, with more than 4 million new cases occurring each year. BCC is derived from basaloid epithelial cells. For white persons older than 65 years, there is a 40% lifetime chance of developing a BCC. BCCs are caused by mutations in one or more genes of the hedgehog signaling pathway, with the most common mutation occurring in PTCH1 . The major cause of BCC is long-term ultraviolet (UV) light exposure, punctuated by intense overexposure (sunburns). Less often, BCC may occur from genetic disorders (e.g., basal cell nevus syndrome), excessive arsenic ingestion, or radiation or chronic trauma (e.g., vaccination scars, tattoos).
Clinical Features
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Most BCCs occur in adults and elderly persons, especially those with a history of excess sun exposure.
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Most BCCs develop on sun-exposed skin, but occasionally it may occur on non–sun-exposed skin.
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BCC is usually a solitary process, but because of the degree of solar damage that is present in some persons, multiple separate lesions are not uncommon.
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Subtypes of BCC include the following:
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Nodular ( Fig. 30.1 ): BCC presenting as a translucent (pearly) papule or nodule, often with central ulceration ( Fig. 30.2 ), variable telangiectasias, and possible pigmentation (particularly in persons with darker skin and eyes). Pigmented BCC may be difficult to differentiate from melanoma ( Fig. 30.3 ). This is the most common BCC subtype in the head and neck area.
Fig. 30.1
Patient with nodular basal cell carcinoma, with a translucent quality, and telangiectasia.
(From the Fitzsimons Army Medical Center Collection, Aurora, CO.)
Fig. 30.2
Patient with small, ulcerated, papular basal cell carcinoma.
(From the John Aeling Collection, Aurora, CO.)
Fig. 30.3
Patient with ulcerated basal cell carcinoma composed of an admixture of translucent and pigmented areas.
(From the Fitzsimons Army Medical Center Collection, Aurora, CO.)
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Superficial spreading BCC: plaque-like lesions with translucent papules at the periphery and a pattern of chiefly horizontal growth. This variant is most common on the trunk, especially the back ( Fig. 30.4 ).
Fig. 30.4
Patient with basal cell nevus syndrome with nodular and superficial basal cell carcinomas, including some that are focally pigmented.
(From the Fitzsimons Army Medical Center Collection, Aurora, CO.)
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Infiltrative, desmoplastic, and morpheaform BCC: morphologic growth types that often yield smaller or invasive basaloid islands admixed in a variable collagenous or even keloidal stroma. Clinically, these types of BCCs may be deceptive in appearance, resembling an otherwise unexplained scar.
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Diagnosis
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BCC is often suspected based upon the clinical appearance, but final assessment and treatment require a biopsy to prove the diagnosis. Management is affected by the histologic growth pattern observed.
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The biopsy technique is determined by the clinical appearance and characteristics of the lesion, but a shave, punch, incisional, or excisional biopsy may be employed.
Treatment
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BCC is a malignant process, and complete surgical extirpation is the treatment modality most often utilized.
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Electrodessication and curettage is a therapeutic option for cases of superficial or nodular BCC, but this technique does not allow for histologic confirmation of uninvolved surgical margins.
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Mohs (micrographically controlled) surgery is the treatment of choice of large BCCs of the face, for tumors with infiltrative, desmoplastic, and/or morpheaform histology, and for many recurrent BCCs.
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Less often, radiation (primarily for large tumors in elderly patients), photodynamic therapy (PDT), cryosurgery, or topical imiquimod and 5-fluorouracil (superficial forms only) may be used.
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Vismodegib and sonidegib represent hedgehog pathway inhibitors used for locally aggressive or rare metastatic BCC or documented basal cell nevus syndrome, but this is the domain of experts.
Clinical Course
BCC represents a malignant process that can destroy normal structures, and it may even extend into bone. Metastatic BCC is a rare event, but it can occur, with more than 350 cases reported in the medical literature.
Spitz Nevus
ICD10 code D22 (site dependent)
BENIGN NEOPLASM
Pathogenesis
Spitz nevi are benign melanocytic neoplasms that are tumors difficult to differentiate from melanoma. The original cases, described by Dr. Sophie Spitz, were called benign juvenile melanoma , because of histologic similarities to melanoma, but a generally indolent course. Most Spitz nevi are skin-colored, pink, or red and are nondescript in clinical appearance. The terms atypical Spitz nevus and atypical Spitzoid tumor (AST) are more recent terms used to describe lesions of uncertain biologic potential that are difficult to differentiate from spitzoid melanoma, even using light microscopy, immunostains, and genetic analysis. Desmoplastic Spitz nevi are lesions characterized by increased stroma, including activated fibroblasts and dense collagen.
Clinical Features
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Spitz nevi occur mostly in whites, of any age, but often in children and adolescents.
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Spitz nevi are typically solitary, but multiple lesions, or even agminated lesions, may occur.
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Spitz nevi present as a papule or nodule that may be dome shaped or even pedunculated.
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Most Spitz nevi are skin-colored, pink, or red, perhaps with telangiectasia ( Figs. 30.5 and 30.6 ). Less often, the lesions are pigmented or resemble other pigmented melanocytic neoplasms.
Fig. 30.5
Patient with slightly red papule, with white globules representing aggregates of keratin.
(From the William Weston Collection, Aurora, CO.)
Fig. 30.6
Patient with Spitz nevus presenting as a red papule with focal telangiectasia.
(From the Fitzsimons Army Medical Center Collection, Aurora, CO.)
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Spitz nevi may have overlying scale and/or small keratinous globules that appear white (see Fig. 30.5 ).
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Historically, most Spitz nevi are of stable size. Rapid growth can occur but is a concerning feature for an atypical Spitz tumor or spitzoid melanoma, and the threshold of biopsy is greatly reduced.
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Spitz nevi may arise on normal skin or in other lesions, including junctional nevi, compound nevi ( Fig. 30.7 ), intradermal nevi, and nevus spilus ( Fig. 30.8 ).
Fig. 30.7
Patient with Spitz nevus arising in a compound nevus.
(From the William Weston Collection, Aurora, CO.)
Fig. 30.8
Patient with multiple red Spitz nevi occurring within a nevus spilus. The smaller brown lesions are compound and junctional nevi.
Diagnosis
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Some Spitz nevi are suspected chiefly on clinical grounds. The occurrence of a pink or red papule on the skin of a young white child raises the possibility of a Spitz nevus.
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Spitz nevi with a marked red color may be confused with vascular tumors, such as pyogenic granulomas.
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A final diagnosis is established by shave, punch, or excisional biopsy. The histologic diagnosis is problematic, and it is wise to have any potential Spitz nevus evaluated by an expert dermatopathologist, because some cases are difficult to differentiate from melanoma, especially in adults.
Treatment
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The treatment of Spitz nevi is not standardized. Although some pediatric dermatologists do not re-excise classic Spitz nevi in a child, even when the surgical margin is involved, a 2002 study showed that most dermatologists prefer conservative complete removal of all Spitz nevi.
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The management of atypical Spitz nevi and ASTs is also not standardized, but these lesions are widely considered to have uncertain biologic potential. Nearly all experts recommend complete surgical extirpation, with some authorities even recommending a 1cm clinical margin. The value of a sentinel lymph node (SLN) sampling in an atypical Spitz nevus or AST is unknown. Some series have shown SLN involvement in up to one-third of cases but with dubious prognostic significance.
Clinical Course
The clinical course of Spitz nevi that are not biopsied has never been studied, and never will be studied. The prevalence of Spitz nevi in children and adolescents, relative to that of adults and geriatric patients, suggests that such lesions involute or evolve into conventional nevi. A longitudinal study of suspected Spitz nevi by dermoscopy, with a mean follow-up of 25 months, has revealed dermoscopic features of involution in 80% of the lesions, with the remaining 20% stable or enlarging.
Dermatofibroma
ICD10 code C23 (site dependent)
BENIGN NEOPLASM
Pathogenesis
A dermatofibroma, also known as cutaneous fibrous histiocytoma, is a common tumor of fibrohistiocytic origin. There is debate as to whether dermatofibromas represent a neoplastic or reactive process. In support of the former is the development of lesions at sites of injury (e.g., shaving trauma on the legs, insect bites), but studies of the methylation pattern of the polymorphic X chromosome−linked androgen receptor have demonstrated that dermatofibromas are clonal proliferations, and are probably neoplastic.
Clinical Features
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Most dermatofibromas occur in persons 20 to 50 years of age, with a slight female predominance.
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Patients may report a history of preceding trauma (e.g., shaving trauma on the legs of women, insect bites).
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Most dermatofibromas occur on the lower extremities but also on the trunk, head, and neck.
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Most dermatofibromas are round to oval, firm, painless papules or nodules. The lesion may be exophytic, dimpled, or flat, with a color that varies from skin-colored to tan to brown to violaceous ( Figs. 30.9 and 30.10 ).
Fig. 30.9
Brownish-violaceous nodule on the leg of a woman.
(From the William Weston Collection, Aurora, CO.)
