As the population continues to age, clinicians and dermatologists are increasingly faced with geriatric patients presenting with a range of dermatologic manifestations, including benign and malignant skin tumors. Knowledge of epidemiologic and morphologic features, including dermoscopy of common and benign melanocytic and nonmelanocytic skin tumors, provides the basis for a better understanding and management of problematic skin tumors in this age group. This article provides an overview of common and problematic skin lesions in elderly patients and addresses epidemiologic, clinical, and dermoscopic clues that aid the differential diagnosis and management of challenging skin lesions.
Key points
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The age shift in the population has resulted in an overall increase in total number of melanoma and nonmelanoma skin cancers.
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Compared with younger individuals, older persons participate less frequently in skin cancer screening programs, and therefore opportunistic skin cancer screening should be promoted in this age group.
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Signs of actinic damage or the presence of suspicious skin lesions at visible body sites, such as the face or forearms, should be considered important risk factors for additional melanoma or nonmelanoma skin cancer located on generally uncovered body sites, such as the torso.
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Nevus count decreases after the fourth decade of life, and therefore elderly patients usually present with few, mainly banal intradermal nevi.
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Any newly developing, growing, or large melanocytic skin lesion in elderly patients should raise the suspicion of melanoma or nonmelanoma skin cancer.
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Awareness of the clinical and dermoscopic features of histopathologically challenging melanocytic skin lesions helps avoid misclassification of melanoma and inadequate treatment.
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Knowledge of the clinical and dermoscopic features of the most common benign skin lesions in the elderly aids the recognition of potentially suspicious skin lesions.
Introduction
Defining the Elderly
The boundary between middle and old age cannot be defined exactly, because it does not have the same meaning in all races and societies. Accordingly, the definition of an “elderly” or “old” person is somewhat arbitrary. However, most developed world countries have accepted the chronologic age of 60 years and older as a definition of “elderly.”
The Process of Skin Aging
Human skin undergoes chronologic changes, which affect the structure and function of the skin. The process of aging is influenced by intrinsic (physiologic aging) and extrinsic (photoaging) factors.
Age-related changes include progressive thinning of the epidermis with loss of undulating rete pattern, decreased cell replacement of the epidermis, increased blood vessel fragility, dryness, and reduced wound healing. The number of melanocytes, fibroblasts, and Langerhans cells is decreased, causing changes in skin pigmentation, elasticity, and barrier function.
All of these changes contribute to certain dermatologic conditions, which are more commonly ascribed to the elderly. These disorders encompass a diverse array of etiologically unrelated degenerative, autoimmune, idiopathic, and neoplastic conditions that may impact quality of life and produce significant morbidity and mortality.
As the population ages, a more complete understanding of clinical and histopathologic features unique to the geriatric dermatologic patient becomes essential.
The Magnitude of the Problem
More than 36 million people older than 65 years were alive in the United States in 2004, representing approximately 12% of the population. By 2030, this number will increase to 71 million, accounting for approximately 20% of the population.
Skin diseases of the elderly will therefore represent a significant part of general dermatology in the near future. Studies evaluating the prevalence of skin diseases in geriatric dermatology identified benign and malignant skin tumors among common reasons for consultation.
This article reviews the epidemiologic, clinical, and dermoscopic features of common and problematic skin tumors in the elderly, and provides clues and rules for their diagnosis, management, and treatment.
Introduction
Defining the Elderly
The boundary between middle and old age cannot be defined exactly, because it does not have the same meaning in all races and societies. Accordingly, the definition of an “elderly” or “old” person is somewhat arbitrary. However, most developed world countries have accepted the chronologic age of 60 years and older as a definition of “elderly.”
The Process of Skin Aging
Human skin undergoes chronologic changes, which affect the structure and function of the skin. The process of aging is influenced by intrinsic (physiologic aging) and extrinsic (photoaging) factors.
Age-related changes include progressive thinning of the epidermis with loss of undulating rete pattern, decreased cell replacement of the epidermis, increased blood vessel fragility, dryness, and reduced wound healing. The number of melanocytes, fibroblasts, and Langerhans cells is decreased, causing changes in skin pigmentation, elasticity, and barrier function.
All of these changes contribute to certain dermatologic conditions, which are more commonly ascribed to the elderly. These disorders encompass a diverse array of etiologically unrelated degenerative, autoimmune, idiopathic, and neoplastic conditions that may impact quality of life and produce significant morbidity and mortality.
As the population ages, a more complete understanding of clinical and histopathologic features unique to the geriatric dermatologic patient becomes essential.
The Magnitude of the Problem
More than 36 million people older than 65 years were alive in the United States in 2004, representing approximately 12% of the population. By 2030, this number will increase to 71 million, accounting for approximately 20% of the population.
Skin diseases of the elderly will therefore represent a significant part of general dermatology in the near future. Studies evaluating the prevalence of skin diseases in geriatric dermatology identified benign and malignant skin tumors among common reasons for consultation.
This article reviews the epidemiologic, clinical, and dermoscopic features of common and problematic skin tumors in the elderly, and provides clues and rules for their diagnosis, management, and treatment.
Common melanocytic skin lesions
Age-Related Nevus Pattern
The nevus count and prevailing nevus patterns are well documented as being influenced by age and body site. Nevus count increases from childhood to midlife, and decreases thereafter. This dynamic is reflected by the phrase “we are born and we will die without nevi” ( Fig. 1 ).
Histopathologic and dermoscopic studies report on a high prevalence of intradermal and compound nevi in both children and the elderly, dermoscopically characterized by a globular and structureless pattern, respectively. Moreover, a small subset of compound nevi in adolescents will exhibit a peripheral rim of small brown globules; this dermoscopic pattern is a sign of growth as these nevi enlarge symmetrically with time, accompanied by a progressive development of reticular pattern, until the disappearance of peripheral globules indicates their growth stabilization. Finally, most adults are prone to junctional or superficial compound nevi (eg, Clark nevi) with a dermoscopic reticular pattern.
The age-related differences between nevus subtypes have led to the hypothesis that nevogenesis occurs through at least 2 distinct pathways. One, the congenital or constitutional pathway, gives rise to globular or structureless nevi, with onset during childhood. These nevi are thought to derive from predominantly dermal melanoblasts (ie, not fully mature melanocytes), which represent persisting small congenital nevus-like proliferations that acquire the typical appearance of an intradermal nevus of the Miescher or Unna type with time.
In contrast, the acquired or exogenous pathway is responsible for the formation of reticular nevi (ie, flat, Clark nevi), which initially exhibit a peripheral rim of small brown globules. These nevi are hypothesized to derive from predominantly intraepidermal melanocytes (ie, mature melanocytes), which proliferate in response to factors such as intermittent ultraviolet light exposure. These nevi seem to progressively disappear after the fourth decade of life because of involution, regression, or apoptosis.
The dynamic of reticular nevi is further supported by 2 recent studies. The first study investigated the frequency of dermoscopic nevus subtypes by age and body site in a study cohort aged between 2 to 101 years, and showed that the number of evolving nevi, dermoscopically characterized by a peripheral rim of brown globules, increases from childhood until the second decade of life, and thereafter decreases rapidly. Notably, no evolving nevus was detected in subjects older than 60 years.
The second study investigated the frequency of nevus subtypes by body site and age in a cohort aged between 60 and 89 years, and reported that nevus counts in persons older than 60 years continue to decrease, noting that this reduction was largely attributable to a reduction of flat, reticular (Clark) nevi. In contrast, structureless intradermal nevi (Unna and Miescher type) persisted even into the oldest age (ie, >89 years).
Body Site–Related Patterns of Melanocytic Nevi
In addition to the age-related patterns, studies suggest that the prevailing nevus type and pattern are also influenced by the anatomic body site.
Several clinical and dermoscopic studies report a high frequency of nodular nevi (ie, intradermal nevi) on the head and neck area and upper trunk (shoulders), compared with flat and reticular nevi (ie, mostly superficial compound or junctional nevi), which can be seen in any area of the trunk but are particularly common on the extremities.
These epidemiologic and morphologic data show that most elderly present with few, mostly intradermal, common nevi, whereas evolving nevi showing peripheral globules or large, flat, junctional (ie, reticular) melanocytic proliferations can be regarded as uncommon. This knowledge has practical implications for the diagnosis and management of some, potentially conflicting, melanocytic skin lesions in the elderly.
Problematic melanocytic skin lesions in the elderly
Growing Melanocytic Lesions
Although evolving nevi in adolescence are an expected finding, and therefore do not require further interventions, a melanocytic skin lesion showing signs of growth (ie, with peripheral rim of brown globules) after 50 years of age should be viewed with great caution. The presence of peripheral globules in these older individuals can be the clue to the diagnosis of an otherwise elusive melanoma; management options include excision or close observation ( Fig. 2 ).
Regarding the choice of monitoring (ie, short-term monitoring after 3 months or long-term monitoring after 12 months), a recent study investigating the growth patterns of melanomas detected during digital dermoscopic monitoring revealed that melanomas exhibiting globules may grow faster than melanomas characterized by a reticular pattern (ie, slow-growing melanoma). As a consequence, an equivocal melanocytic skin lesion showing globules or streaks dermoscopically (both are important signs of growth) should be scheduled for short-term monitoring (ie, follow up after 2–3 months), because long-term monitoring (ie, follow up after 12 months) in the case of fast-growing melanoma could result in significant increase of tumor thickness and its related consequences.
Another interesting aspect regarding changing melanocytic nevi is provided by a recent study, which assessed the age-related frequency of changing nevi during short-term monitoring. As expected, changing nevi were significantly associated with young age (0–18 years), and most nevi were reported to be banal on histopathology. Surprisingly, changing nevi were also significantly more frequent in the oldest age group (>65 years) than in middle-aged patients (36–65 years); however, in contrast to the younger age group, excised changing nevi in the elderly were more often histopathologically referred to as “dysplastic.” Whether this may be related to a histopathologic underestimation of early melanomas in this age group remains to be further clarified. However, signs associated with involution (ie, any loss of structure or pigmentation) were seen in approximately 38% of changing nevi, whereas 27.6% of nevi showed an increase in size (of which 62.5% showed an asymmetric size increase). Further studies are needed to better understand the biologic significance of changing lesions in the elderly.
Atypical Lentiginous Junctional Melanocytic Nevus
In 1991, Steven Kossard described a peculiar histopathologic type of melanocytic proliferation commonly located on chronically sun-damaged skin of elderly patients, which he named atypical lentiginous junctional nevus of the elderly .
Ongoing debate exists regarding whether atypical lentiginous junctional melanocytic proliferations of the elderly should be regarded as nevi with a potential risk of progression toward melanoma, or instead represent a very initial form of slow-growing melanoma in situ on sun-damaged skin. The latter view is further supported by studies reporting on associated melanomas in 38% to 75% of these junctional lesions, and the often-large size of the lesions, suggesting continuous growth.
From a clinical standpoint, these discussions are practically irrelevant, because these lesions should be managed as if they would be melanoma in situ; in other words, complete excision with clear margins is recommended.
Clinically, these atypical lentiginous junctional melanocytic proliferations of the elderly are commonly located on the upper back, shoulders, or extremities, and present as solitary, often large (>8 mm), ill-defined macules with nuances of black, brown, gray, or white. Dermoscopically, these lesions are typified by a more or less atypical pigmented network, diffuse structureless brown pigmentation, and areas of regression ( Fig. 3 ). Digital dermoscopic follow-up studies suggest that these lentiginous atypical melanocytic proliferations may belong to a group of slow-growing melanomas, which show only subtle time-related changes and occasionally require several years to be finally recognized by digital monitoring.
Nested Melanoma of the Elderly
Nested melanoma of the elderly was only recently described, and represents a distinct morphologic variant of superficial spreading melanoma. Given its recent identification, epidemiologic and prognostic data are scarce. Histopathologically, nested melanoma is characterized by large intraepidermal nests of melanocytes, which correspond dermoscopically to variable, large, brown to black globules over a structureless brown background that do not follow any specific arrangement.
Problematic lesions related to special anatomic body areas
Flat Pigmented Facial Lesions
The clinical recognition of lentigo maligna in the mottled chronic sun-damaged skin can be challenging, because it shares many clinical features with other pigmented macules that commonly arise on sun-damaged skin. These macules include particularly nonmelanocytic skin lesions, such as solar lentigo, flat seborrheic keratosis, regressing seborrheic keratosis (lichen planus–like keratosis), and pigmented actinic keratosis (AK).
Notably, the list of differentials never includes “melanocytic nevus”; this can be explained by the fact that nevi on the head/neck area of elderly are usually dome-shaped, well-defined, often hypopigmented nodules (ie, intradermal nevus of the Miescher type), whereas lentigo maligna is flat and pigmented ( Fig. 4 ).
Accordingly, the clinical appearance of a nevus on the head and neck differs from that of lentigo maligna, and therefore a nevus is not considered in the differential diagnosis of flat, facial pigmented macules. This omission is further supported by a study in which no single, flat, dermoscopically reticular nevus was found on the face of subjects older than 60 years.
Although this concept based on epidemiologic and clinical data sounds simple and logic, it is often only unconsciously applied in clinical practice and, accordingly, the histopathologic diagnosis of a “junctional or lentiginous nevus” of a flat, often large (>6 mm) pigmented macule on the head and neck region in an elderly patient is accepted without sufficient criticism of its clinicopathologic validity.
In fact, on histopathologic analysis, early lentigo maligna may lack significant cytologic atypia or architectural disarrangement, making its differentiation from a lentiginous or junctional nevus challenging ; however, knowledge about the stereotypical clinical appearance of facial nevi in the elderly provides an important criterion and clue to avoid misdiagnosing an early facial melanoma as a junctional nevus.
Nevertheless, the differential diagnosis between lentigo maligna, solar lentigo, pigmented AK, and lichen planus–like keratosis remains challenging and requires consideration of important criteria, such as number of lesions, lesions surface, and color.
In the authors’ experience, lentigo maligna commonly presents as a solitary, brown, poorly demarcated macule with a smooth surface; in contrast, solar lentigines and pigmented actinic keratoses are commonly numerous and reveal a rough-to-scaly surface. On dermoscopy, the single most important criterion for differentiating between benign and potentially malignant macules is related to the color; solar lentigo usually exhibits only brown color, whereas lentigo maligna or pigmented AK commonly reveal a combination of brown and gray ( Fig. 5 ). One exception is pigmented AK and lichen planus–like keratosis, which also show gray color on dermoscopy. In these cases, a biopsy is required.
Differential Diagnosis of Nodular Facial Lesions
Similar to nevi, the morphologic patterns of basal cell carcinoma (BCC) are influenced by age and body site. Most BCCs on the head and neck area are nodular, whereas flat, superficial BCCs are most commonly located on the trunk and lower extremities. Accordingly, the leading differential diagnosis of facial dermal nevus is nodular BCC.
Dermoscopy is helpful to differentiate between both entities through disclosing different vascular and/or pigmented patterns. Vessels in intradermal nevi are usually blurred, curved, and show few ramifications. If pigment is present, it will often appear as structureless brown-gray. Instead, vessels in nodular BCC are usually dull red and sharply focused, and reveal ramifications into the finest capillaries ( Fig. 6 ). In the case of pigmentation, often blue-gray roundish structures of variable size are seen.
