III.15.1 Definition
Recurrent nevi, also called persistent nevi, are frequently observed following incomplete exci- sion by superficial shaving techniques, an ordi- nary procedure for the management not only of dermal nevi but also of Clark nevi in the daily routine of a busy dermatological out-patient service. Recurrent nevi are pigmented skin le- sions that clinically, dermoscopically, and also histopathologically are commonly interpreted as melanoma in situ or superficial melanoma.
III.15.2 Clinical Features
Recurrent nevi usually appear as asymmetric, bizarrely outlined, and poorly circumscribed patches with a dark-brown to black pigmenta- tion resembling a superficial melanoma. As a rule, a scar is present around this pigmented le- sion, although in some instances the scar is dif- ficult to detect and only anamnestic data lead to the diagnosis of recurrent nevus. Obviously, the
Chapter III.15
Recurrent Nevus
Andreas Blum
III.15
Contents
III.15.1 Definition . . . .147
III.15.2 Clinical Features . . . .147
III.15.3 Dermoscopic Criteria . . . .147
III.15.3 Relevant Clinical Differential Diagnosis . . . .149
III.15.4 Histopathology . . . .149
III.15.5 Management . . . .149
References . . . .150
most important differential diagnosis is recur- rent/persistent melanoma and re-evaluation of the original histopathological specimen is man- datory for a definite diagnosis [12].
III.15.3 Dermoscopic Criteria
Dermoscopically, recurrent nevi are usually characterized by the presence of a homogeneous or multicomponent pattern with a prominent dark-brown to black coloration. An atypical pigment network, irregular streaks, and black dots are commonly observed in recurrent nevi.
Due to this established features, dermoscopy in- creases the diagnostic accuracy in comparison with the clinical investigation with the naked eye (Fig. III.15.1, III.15.2) [1–3]. However, no study which has described typical dermoscopic features of recurrent nevi has been publish- ed thus far; therefore, this chapter describes recurrent nevi in dermoscopy and compares them with the features of melanoma in -situ (Fig. III.15.3, III.15.4).
The following features were based on a study of more than 2500 benign and 200 malignant histopathologically proven melanocytic lesions [4]. Six recurrent nevi and 12 melanoma in situ were found in this database [5].
The results of this first observation are given in Table III.15.1. Recurrent nevi showed mostly a symmetric centrifugal pattern from the center of the scar with different dermoscopic struc- tures in one melanocytic lesion. In all 6 cases, a hyperpigmentation at the periphery was not present. Within and in the surroundings of the lesion, reddish areas with vessels could be seen.
In our series of melanomas in situ mostly an asymmetric pattern with a hyperpigmentation
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at the periphery was observed. Also, several dif- ferent dermoscopic structures and colors were present. The pattern of growth was not regular and not centrifugal. Also, no reddish surround- ings and vessels could be detected.
The dermoscopic pattern of recurrent nevi can be compared with a “bunch of flowers”
when the observer is looking at it from the top.
The growth pattern of a melanocytic lesion has an important impact for the benign or malig- nant potential of the lesion [7]. In the case of a hyperpigmentation at the periphery a precursor of a melanoma or an initial melanoma must be excluded. In contrast, when the pigmentation has a centrifugal pattern, the melanocytic lesion is benign [8].
Fig. III.15.1. Recurrent nevus, dermoscopy view. Note an irregular outlined whitish halo representing a superfi- cial scar caused by a shaving biopsy. The centrally situated recurrent nevus is dermoscopically virtually indistin- guishable from a melanoma in situ. The patient’s history is crucial for the diagnosis
Fig. III.15.2. Recurrent nevus, dermoscopy view. The whitish halo here is regular and not so prominent. The recurrent nevus in the center is charaterized by irregular blue blotches
Fig. III.15.3. Melanoma in situ, dermoscopy view. Be- sides the lack of a surrounding scar, this melanoma in situ could dermoscopically easily be mixed with a recurrent nevus
Fig. III.15.4. Melanoma in situ, dermoscopy view. Also this irregularly outlined black lesion shares morphologi- cal features with a recurrent nevus
Recurrent Nevus Chapter III.15 149
III.15.3 Relevant Clinical Differential Diagnosis
Recurrent nevi may simulate melanoma clini- cally by being asymmetric, poorly circum- scribed, and irregularly pigmented. Complete clinical history is crucial for the diagnosis, in order to rule out the possibility of a melanoma recurring after incomplete excision.
III.15.4 Histopathology
For a correct histopathological diagnosis of a re- current nevus, the former report of histopathol- ogy must be present. If this report is not avail- able, e.g., due to former laser therapy without any histopathology, the histopathologist may have great difficulties differentiating between a recurrent nevus and melanoma.
A particular pitfall is represented by melano- cytic tumors recurring after laser vaporization (or other types of surgical treatment without histopathological verification of the clinical di- agnosis). In such cases, the diagnosis relies only on the histopathological features.
Usually patients give information about for- mer surgery which can support the diagnosis of a possible recurrent nevus. In some cases, how-
ever, the history is not clear or even not given, e.g., in some cases of teledermatology [6].
Recurrent nevi are characterized histopatho- logically by the proliferation of melanocytes above a scar. Intraepidermal melanocytes are arranged mainly as solitary units disposed in all levels of the epidermis, thus simulating mela- noma; however, the atypical growth of melano- cytes is strictly confined to the area where scar tissue is present in the dermis (by contrast, me- lanocytes of recurrent melanoma extend beyond the lateral margins of the scar). Complexes of the pre-existing nevus are often detectable be- low the scar and/or at the side of the lesion.
III.15.5 Management
The clinical and dermoscopic features of recur- rent nevus together with the history of removal of a previous nevus at the same site are quite characteristic, still a recurrent melanoma often cannot be ruled out with certainty; therefore, complete surgical excision and subsequent histopathological examination of a suspicious recurrent nevus is strongly recommended in order not to overlook a recurrent/persistent melanoma.
Table III.15.1. Results of study
Recurrent nevus Melanoma in situ Features
Symmetry Present Not present
Hyperpigmentation at the periphery Not present Present
Dermoscopic structures Few Many
Colors Few Many
Pattern of growth Centrifugal Not regular
Reddish surrounding Present Not present
Vessels Present Rare
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CCore Messages
■ Recurrent nevi are very frequently observed following incomplete excision by superficial shaving techniques.
■ They usually appear as asymmetric, bizarrely outlined, and poorly circum- scribed patches with a dark-brown to black pigmentation.
■ As a recurrent melanoma often cannot be ruled out with certainty, complete surgical excision and subsequent histopathological examination is strongly recommended.
References
1. Mayer J (1997) Systematic review of the diagnostic accuracy of dermatoscopy in detecting malignant melanoma. Med J Aust 167: 206–210
2. Kittler H, Pehamberger H, Wolff K, Binder M (2202) Diagnostic accuracy of dermoscopy. Lancet Oncol 3: 159–165
3. Argenziano G, Soyer HP, Chimenti S et al. (2003) Dermoscopy of pigmented skin lesions: results of a consensus meeting via the Internet. J Am Acad Der- matol 48: 679–693
4. Bauer J, Metzler G, Rassner G, Garbe C, Blum A (2001) Dermatoscopy turns histopathologist’s at- tention to the suspicious area in melanocytic le- sions. Arch Dermatol 137: 1338–1340
5. Blum A, Luedtke H, Ellwanger U, Schwabe R, Rass- ner G, Garbe C (2004) Digital image analysis for diagnosis of cutaneous melanoma. Development of a highly effective computer algorithm based on analysis of 837 melanocytic lesions. Br J Dermatol 151: 1029–1038
6. Blum A. Hofmann-Wellenhof R, Luedtke H, Ell- wanger U, Steins A, Roehm S, Garbe C, Soyer HP (2004) Value of the clinical history for different us- ers of dermoscopy compared with results of digital analysis. J Eur Acad Dermatol Venereol 18: 665–
7. Blum A, Soyer HP, Garbe C, Kerl H, Rassner G, Hof-669 mann-Wellenhof R (2003) The dermoscopic classi- fication of atypical melanocytic nevi (Clark nevi) is useful to discriminate benign from malignant me- lanocytic lesions. Br J Dermatol 149: 1159–1164 8. Braun RP, Lemonnier E, Guillod J, Skaria A, Salo-
mon D, Saurat J (1998) Two types of pattern modi- fication detected on the follow-up of benign mela- nocytic skin lesions by digitized epiluminescence microscopy. Melanoma Res 8: 431–435
9. Menzies SW, Gutanev A, Avramidis M, Batrac A, McCarthy WH (2001) Short-term digital surface microscopic monitoring of atypical changing mela- nocytic lesions. Arch Dermatol 137: 1583–1589 10. Bauer J, Blum A, Strohäcker U, Garbe C (2005)
Surveillance of patients at high risk for cutaneous malignant melanoma using digital dermoscopy. Br J Dermatol 152: 87–92
11. Skvara H, Teban L, Fiebiger M, Binder M, Kittler H (2005) Limitation of dermoscopy in the recognition of melanoma. Arch Dermatol 141: 155–160 12. Kornberg R, Ackerman AB (1975) Pseudomelano-
ma: recurrent melanocytic nevus following partial surgical removal. Arch Dermatol 111:1588–1590
