Epithelioid blue nevus: neoplasm Sui generis or variation on a theme?

The epithelioid blue nevus has recently been associated with the Carney complex, which is characterized by myxomas, spotty skin pigmentation, endocrine overactivity, and schwannomas. Using the general criteria proposed by Carney and Ferreiro, similar lesions were identified in 33 patients with no evidence of the Carney complex. Those lesions presented on the face, trunk and extremities of 15 males and 18 females. The mean age was 35 years, much older than those in the Carney complex (mean 16.3 years). Clinical diagnoses included malignant blue nevus, atypical nevus, melanoma, congenital nevus, and dermatofibroma. The lesions were symmetric, predominantly dermal melanocytic proliferations arranged as short fascicles, small nests, and single cells. Large polygonal and epithelioid melanocytes with moderate pleomorphism, and occasional nuclear pseudoinclusions were admixed with heavily pigmented dendritic and spindled melanocytes and melanophages. Rare mitotic figures were seen in some cases. The neoplasms showed a morphologic spectrum that encompassed a group of combined blue nevi with epithelioid melanocytes and other Spitz's nevus characteristics. These epithelioid combined nevi (ECN) fell into three phenotypes with morphologies that most closely paralleled those pictured by Carney and Ferreiro in the Carney complex: the classic or Carney complex pattern (ECN-CC), those that showed overlap with deep penetrating nevus (ECN-DPN), and those that have many dermal Spitz's nevus features, [BLue + SpITZ's nevus; (ECN-BLITZ)I. In six cases, there was such an admixture of features that it was difficult to ascribe them to one of the groups. Nine lesions had associated banal congenital nevus. Follow-up that averaged over 2.5 years (31 months) (range 6-162 months) showed no evidence of malignancy or recurrent disease after excision. Epithelioid combined nevus is a type of combined nevus with blue nevus and Spitz's nevus features, which may or may not be associated with the Carney complex. It shows morphologic overlap with the epithelioid blue nevus described by Carney (ECN-CC), deep penetrating nevus (ECN-DPN), and blue nevus with intradermal Spitz's (desmoplastic) nevus (ECN-BLITZ). Epithelioid combined nevus is thought to be a fitting nosologic designation for all of these lesions.     

"Atypical" Spitz's nevus, "malignant" Spitz's nevus, and "metastasizing" Spitz's nevus: a critique in historical perspective of three concepts flawed fatally

Our purpose in undertaking this Arbeit was to review all articles published about "atypical" Spitz's nevus, "malignant" Spitz's nevus, and "metastasizing" Spitz's nevus, to criticize them in a fashion that illuminates, and to come to conclusions compellingly about those subjects. We found that an overwhelming majority of neoplasms that claimed to be "atypical Spitz's nevus," "metastasizing Spitz's nevus," and "malignant Spitz's nevus" were, in fact, melanomas ( Table 1). Moreover, in our estimation, those designations, and variants of them, like "atypical Spitz's lesion," "atypical dermal melanocytic lesion with features of Spitz's nevus," "atypical Spitzoid melanocytic neoplasm," and "problematic Spitzoid melanocytic lesion," are mere evasions from a diagnosis, straightforwardly, of either Spitz's nevus or melanoma. Diagnoses in pathology equally bogus are "minimal deviation melanoma," "borderline melanoma," "nevoid melanoma," "potentially low-grade melanocytic neoplasm," and "melanocytic lesion of uncertain biologic potential." Rather than admit uncertainty forthrightly, those who employ circumlocutions like those just mentioned resort to linguistic maneuvers that, at first blush, seem to be "academic" and constructed in such a way as to appear to convey confidence, rather than tentativeness, on the part of a histopathologist. On further scrutiny, however, each of those cliches is revealed to be devoid of content. For example, "malignant" Spitz's nevus and "metastasizing" Spitz's nevus not only are contradictions in terms, but they are outrageous violations of fundamental principles of classic Virchowian pathology, and "atypical" Spitz's nevus not only is a redundancy because the neoplasm was so atypical to Spitz, herself, she insisted (from the time she spawned the idea in 194 through 1951 it was a "malignant melanoma," but is abject intellectually, those who invoke it never setting forth, in clear-cut fashion, criteria for what constitutes a "typical" Spitz's nevus in contradistinction to an "atypical" one.     

Deep penetrating nevus-like borderline tumors: A unique subset of ambiguous melanocytic tumors with malignant potential and normal cytogenetics

Background

Deep penetrating nevi (DPN) are a relatively uncommon subtype of melanocytic nevi. A small subset of these lesions exhibit atypical features (cytologic and architectural atypia, mitotic activity) seen in melanoma. These lesions we term the deep penetrating nevuslike borderline tumor. Unequivocal melanomas can show overlapping morphologic features of DPN, which have been termed plexiform melanomas.

Patients and methods

40 cases of DPN-like borderline tumor were identified along with 6 cases of plexiform melanoma. Clinical follow up was obtained, along with cytogenetic analysis in the form of fluorescent in situ hybridization (FISH) and/or comparative genomic hybridization (CGH).

Results

The DPN-like borderline tumor cases included 24 females and 16 males. Of sentinel lymph node biopsies performed, 1/3 of cases showed lymph node involvement. All patients where an aggressive clinical approach was adopted remain free of disease. All 6 DPN-like borderline tumor cases tested by CGH showed normal cytogenetics, as did 7 of 9 cases tested by FISH. Of the plexiform melanomas, 4/6 patients died of disease. In 3 cases there was morphologic progression from a DPN-like borderline tumor to overt melanoma. In one case of progression, cytogenetics was normal in the DPN-like borderline tumor and then abnormal in the progressed melanoma.

Conclusion

DPN-like borderline tumors are melanocytic tumors associated with a high incidence of regional lymph node disease and exhibiting the potential for melanoma progression despite a normal cytogenetic profile. Patients with these lesions should be aggressively managed, with at least complete re-excision and consideration of sentinel node biopsy, regardless of cytogenetic data.

     

Sentinel node biopsy in atypical melanocytic neoplasms in childhood: a single institution experience in 24 patients

Introduction: Sentinel lymph node biopsy (SLNB) is a controversial but frequently used adjunct to wide excision of difficult‐to‐diagnose melanocytic proliferations of childhood. We herein report our institutional experience with SLNB in pediatric patients with these lesions, hereafter referred to as ‘atypical melanocytic proliferations'. Methods: Our prospectively collected melanoma database was queried for patients ≤21 years of age status post‐SLNB for a diagnosis of atypical melanocytic proliferation in which the diagnosis of melanoma ≥1 mm in depth was considered in the differential diagnosis by one or more expert dermatopathologists and for which no diagnostic consensus could be reached. Results: Of 24 patients identified over 17 years, 7 patients (29%) had a positive sentinel lymph node (SLN). Six SLN‐positive patients underwent complete lymph node dissection, with one (14%) having additional nodal involvement identified. With a median follow‐up of 4.1 years (range < 0.1 to 14.8 years), all patients showed no evidence of disease. Conclusions: Despite a significant rate of identification of melanocytes in SLNs of children with atypical melanocytic proliferations, survival appears favorable and controversy surrounding the significance of nodal involvement remains. Further studies with larger numbers of patients and long‐term follow‐up are needed before the true prognostic value of SLNB in this setting can be determined. Mills OL, Marzban S, Zager JS, Sondak VK, Messina JL. Sentinel node biopsy in atypical melanocytic neoplasms in childhood: a single institution experience in 24 patients.     

An atypical melanocytic lesion without genomic abnormalities shows locoregional metastasis

A subset of difficult melanocytic lesions exists with histopathologic features that evade diagnostic consensus from even expert dermatopathologists. Comparative genomic hybridization (CGH) has emerged as a useful diagnostic tool to categorize these lesions, by identifying known chromosomal aberrations in malignant melanoma or the lack thereof in melanocytic nevi. However, determining a lesion's biological behavior primarily on CGH is limited by a relatively small series of corroborative cases without long term follow up. We present a case of a pigmented lesion on the right cheek of a 4 year old boy. The lesion had features of a deep penetrating nevus, but the presence of frequent mitoses, tumor infiltrating lymphocytes, and microscopic foci of tumor necrosis were concerning for an unusual melanoma. We termed this lesion a melanocytic tumor of uncertain potential (MELTUMP) for these reasons. High-resolution array-CGH performed elsewhere on the lesion demonstrated no melanoma-associated genomic abnormalities. A sentinel lymph node biopsy of this patient later revealed multiple small tumor deposits. Although the presence of nodal involvement in similar lesions often do not lead to progressive and fatal disease, this case illustrates that atypical melanocytic lesions with nodal involvement may not demonstrate genomic abnormalities by CGH, and that histopathologic assessment remains paramount in defining these difficult melanocytic lesions. Further comprehensive study of these lesions is needed.     

Polypoid Spitz nevus: two cases evaluated with genetic technique, prolonged follow up, and sentinel lymph node biopsy

Polypoid Spitz nevus represents a spitzoid melanocytic neoplasm that frequently has worrying and challenging histopathological details. Distinction from polypoid melanoma may not be straightforward. Two cases of polypoid Spitz nevus with striking histopathological features were studied. One case had prolonged follow up (Case 1) and one patient had undergone sentinel lymph node biopsy (Case 2), and fluorescence in situ hybridization (FISH) analysis was also completed (both cases). Follow up and genetic analysis of three control cases of polypoid melanoma is also presented. Our clinical and genetic results suggest that both the polypoid Spitz nevi were benign. The patients are alive with no evidence of disease. FISH analysis did not show abnormalities with probes tested. This is in sharp contrast with the control cases of polypoid melanoma, wherein genomic alterations were detectable. Our data indicate that the two polypoid lesions presented here are most probably benign, despite their worrying histopathological features. More cases with long-term follow up and greater numbers of DNA probes are necessary to extend this conclusion to other ambiguous melanocytic tumors.     

Congenital pauci-melanotic cellular blue nevus

Unusual or atypical melanocytic nevi can be confused with malignant melanoma. Two patients are presented here with a rare variant of melanocytic nevus. Both were men. One was 39 years old and sought medical attention after trauma of a "congenital mole". The other was 24 years old and presented with a history of a slowly growing lesion, which had been known since childhood. In both patients, the lesion occurred on the buttock. They were dermal and superficial subcutaneous nodules measuring 1.5 and 2.3 cm in greatest dimension, respectively. The tumors were composed of densely cellular fascicles of melanocytes arranged in a lobulated growth pattern. Rare nests of small epithelioid melanocytes were also seen. No melanin pigment was seen on hematoxylin and eosin-stained sections. Focal minimal pigment was noted by Fontana-Masson stain in one case. Involvement of numerous peripheral nerve trunks by fusiform melanocytes was a prominent feature. Rare mitotic figures were seen in melanocytes [1-2 mitoses per 50 high-power fields (HPF)]. The MIB-1 labeling index was low (less than 5% of the lesional cell population was immunopositive). Both tumors were excised with negative surgical margins. One patient underwent sentinel lymph node biopsy because there was controversy regarding the biologic potential of the lesion. No melanocytic tumor deposits were found in the lymph nodes. On clinical follow up of 11 years and 18 months after complete excision, both patients are alive and well with no evidence of recurrence. We regard these lesions as congenital monophasic and pauci-melanotic variants of cellular blue nevus. The nevi are presented here to enhance our knowledge of the morphologic spectrum of melanocytic tumors and to help avoid confusion with malignant melanoma.     

Nevo de Spitz y otros tumores spitzoides en la infancia. Parte 1: aspectos clínicos,histológicos e inmunohistoquímicos

A Spitz nevus is a melanocytic neoplasm of epithelioid and/or spindle cells that usually appears in childhood. These lesions are by nature benign, but their features can sometimes make them difficult to distinguish from melanomas. Spitzoid melanocytic lesions have been grouped into 3 types in recent decades: Spitz nevi, atypical Spitz tumors, and spitzoid melanomas. Atypical Spitz tumors are spitzoid melanocytic proliferations that have atypical histopathologic features that are insufficient to support a diagnosis of melanoma. The malignant potential of these lesions is at present uncertain. This review examines the clinical, dermoscopic, and histopathologic features of this group of lesions.     

"Atypical" blue nevus, "malignant" blue nevus, and "metastasizing" blue nevus: a critique in historical perspective of three concepts flawed fatally

The same errors that spawned, sustained, and continue to spur the notions of "atypical" Spitz's nevus, "malignant" Spitz's nevus, and "metastasizing" Spitz's nevus are animating of 3 other concepts flawed equally, namely, those of "atypical blue nevus," "malignant blue nevus," and "metastasizing blue nevus." Our intention here is to compel to the conclusion, by way of critique in historical perspective, that all neoplasms claimed to be "malignant blue nevus" and "metastasizing blue nevus;" in fact, are melanomas, that all "atypical blue nevi" are either a nevus or a melanoma, and that the trio of curious designations that serve as title of this work are mere evasions transparently from a diagnosis, straightforwardly, of 1 of only 3 possibilities, to wit, "blue nevus," melanoma, or melanoma in association with a "blue nevus." Rather than admit uncertainty forthrightly, those who employ circumlocutions that we deplore, such as those under scrutiny here, resort to linguistic maneuvers that, at first blush, seem to have the cachet of scholarship (the jargon used being in keeping with a slew of other well-accepted, but equally bogus diagnoses in [dermato]pathology, among those being "minimal deviation melanoma," "borderline melanoma," "nevoid melanoma," "potentially low-grade melanocytic neoplasm," and "melanocytic proliferation of uncertain biologic potential"). All those terms and phrases are constructed in a manner designed to make them appear to convey unbridled confidence on the part of a histopathologist, rather than what they are in actuality, that is, a cover abjectly for tentativeness. Scrutiny of the lingo, in very abbreviated form, just catalogued reveals it to be devoid of content utterly. For example, "malignant blue nevus" and "metastasizing blue nevus" not only are contradictions in terms, but they are outrageous violations of principles fundamental to classic Virchowian pathology. We seek here to debunk that claptrap in the same manner we did "atypical Spitz's nevus," "malignant Spitz's nevus," and "metastasizing Spitz's nevus." It is our hope that readers will consider our arguments worthy because they are logical, will find them convincing because they are irrefutable, and will incorporate the lessons communicated through them so that their own professional life, pathology as a discipline, and, ultimately, patients, are the beneficiaries.     

Pigmented epithelioid melanocytoma: report of first Japanese cases previously diagnosed as cellular blue nevus

Background:  The term 'pigmented epithelioid melanocytoma (PEM)' was recently used for borderline melanocytic tumor/low-grade melanoma including cases previously diagnosed as human animal-type melanoma and epithelioid blue nevus. No Japanese cases have been reported.
Methods:  We reviewed 219 cases previously diagnosed as blue nevus in Japan. Common blue nevus was identified in 154 cases and cellular blue nevus in 65 cases.
Results:  We have found two Japanese cases of PEM previously diagnosed as cellular blue nevus. Two patients were female. The age at presentation was 32 and 28 years. Two lesions were on the buttock. Two cases fulfilled histological criteria proposed for PEM. There is no evidence of recurrence or metastases.
Conclusions:  PEM is a distinct melanocytic tumor and the unifying diagnostic term. PEM is present in Japanese, but these cases may be previously diagnosed as cellular blue nevus. Japanese pathologists should recognize a new concept of PEM, and when they make a diagnosis of PEM, they should be recommended sentinel lymph node sampling.     

Persistent and recurrent blue nevi

Persistence of common melanocytic nevi has been fairly well characterized, clinically and histologically. In contrast, persistence of blue nevi has been reported infrequently. To define this entity better, nine cases of biologically persistent and clinically recurrent blue nevi are described. The persistent lesions in four cases were spindle-fascicular blue nevi; one showed senescent or "ancient" change and one had additional deep penetrating/epithelioid blue nevus features with atypical changes worrisome for malignancy. These changes included increased cellularity, cellular pleomorphism, mitotic figures, and a lymphocytic infiltrate. Three were biphasic dendritic-sclerotic/spindle-fascicular blue nevi, one of which had atypical changes. One case was a dendritic-sclerotic ("common") blue nevus. The original histology in one case was unavailable, but the recurrence was a combined blue nevus. The interval from initial biopsy to biopsy of the recurrent lesion was often longer (mean 2.7 years) for recurrent blue nevi than for recurrent common compound or intradermal melanocytic nevi. In addition, in contrast to recurrent common melanocytic nevi, the recurrence, in at least one case, extended beyond the scar of the original excision. These cases demonstrated that blue nevi of all histiotypes and combinations are capable of persistence with clinical recurrence. The persistence usually was histologically similar to the original, but in some cases was more "cellular" because, for the most part, the excisions of the persistent lesion revealed a deeper spindle-fascicular ("cellular") component not evident in the original superficial biopsy. In two cases, the original blue nevus appeared completely banal, but the persistent/recurrent lesions were histologically distinct and demonstrated atypical histologic features. Yet, follow-up (average 3.7 years) supports benign biology. Clinical recurrence is often associated with malignant transformation in blue nevus, but this series demonstrates that malignant tumor progression is not necessarily the case. In the absence of necrosis en mass, marked cytologic atypia, and frequent mitotic figures, the described atypical morphologic parameters in previously biopsied small blue nevi are probably reactive and "pseudomalignant." Awareness of this potential change may avoid diagnostic and prognostic errors.     

Molecular diagnosis of a benign proliferative nodule developing in a congenital melanocytic nevus in a 3-month-old infant

Small and intermediate congenital melanocytic nevi have a lifetime risk of developing melanoma estimated to range from 0% to 5%. Secondary benign melanocytic proliferations commonly arise in congenital melanocytic nevi; however, some are difficult to definitively distinguish from malignant melanoma based on clinical features and conventional histology. Herein, we describe the use of comparative genomic hybridization in supporting the diagnosis of a deep penetrating nevus developing within a congenital melanocytic nevus of a 3-month-old infant.     

Histologic features of melanocytic nevi seen in association with mycosis fungoides

BACKGROUND: Many different tumors have been reported to occur simultaneously as collision lesions. To date, no such events have been reported between mycosis fungoides (MFs) and melanocytic neoplasms. METHODS: Two cases are presented in which patches of MF were superimposed on melanocytic nevi. In addition, 967 biopsies of MF from 411 patients were identified in an 8-year retrospective database search. Patient pathology history summaries were reviewed to identify inflamed nevi, atypical nevi, and melanoma submitted for histologic evaluation from this population. RESULTS: The occurrence of MF in a congenital nevus was associated with a halo phenomenon restricted to the affected region of the nevus in one patient. In the other patient, nests of two morphologies (lymphocytic and melanocytic) in the same biopsy presented a potentially confusing histologic picture. No other cases of MF superimposed on a nevus were identified in 967 biopsies from 411 patients with a histological diagnosis of MF seen over the past 8 years. In this population, 57 biopsies of melanocytic lesions were identified from 28 patients, including three atypical nevi and three melanomas. CONCLUSIONS: The presence of MF superimposed on a nevus is rare and may lead to confounding histologic features or the development of a halo nevus phenomenon.     

Pediatric "STUMP" lesions: evaluation and management of difficult atypical Spitzoid lesions in children

Spitz nevi represent a distinct type of melanocytic nevi more commonly seen in childhood. Although typically benign, a subset of Spitz lesions raise concern and create a diagnostic dilemma as a result of confusing histology that involves characteristics of classic Spitz nevi intermixed with features of cutaneous melanoma. Such atypical Spitz lesions, or Spitzoid tumors of uncertain malignant potential, are difficult to classify and their biologic potential is uncertain. Nonetheless, these are critical tasks for both prognosis and clinical management. New tools, such as immunohistochemical stains, comparative genomic hybridization, and fluorescence in situ hybridization, have been used to provide further insight into these controversial lesions and to aid in their evaluation. In this review, we present our experience managing 6 cases of Spitzoid tumor of uncertain malignant potential and discuss the potential use of various diagnostic modalities, including sentinel lymph node biopsy, immunostaining, and molecular analysis.     

Spitz nevus and atypical spitzoid neoplasm

Spitz nevus (SN) and Spitzoid malignant melanoma (SMM) represent benign and malignant counterparts at both ends of the spectrum of Spitzoid lesions. Atypical Spitzoid neoplasm (ASN) is a poorly defined and characterized category of melanocytic tumors with histologic features of both benign Spitz nevi and malignant melanomas. The group of ASN represents a mixture of Spitz nevi with atypical features and Spitzoid melanomas. However, at the current moment in time, histopathologists are not capable of differentiating between the 2 in some cases and are forced to place them in this ambiguous category, where the behavior of these lesions cannot be predicted with certainty. Because this group encompasses both benign and malignant lesions, and perhaps also a separate category of melanocytic tumors that behave better than conventional melanomas, some of these neoplasms can metastasize and kill patients, whereas others have no metastatic potential, and yet others might only metastasize to regional lymph nodes. Although diagnostic accuracy has improved over the years, many of these lesions remain controversial, and there is still poor interobserver agreement in classifying problematic Spitzoid lesions among experienced dermatopathologists. The objective of this review article is to summarize the most relevant information about SN and ASNs. At this time histologic examination remains the golden standard for diagnosing these melanocytic neoplasms. We therefore concentrate on the histopathologic, clinical, and dermoscopic aspects of these lesions. We also review the most recent advances in immunohistochemical and molecular diagnostics as well as discuss the controversies and dilemma regarding whether to consider sentinel lymph node biopsy for diagnostically ambiguous melanocytic neoplasms.     

Okkultes dermales Primärmelanom in kongenitalem Nävuszellnävus

Malignant melanomas normally arise at the dermoepidermal junction. Development of these tumours in deeper layers of the dermis without having contact with the junction is rare. A small congenital melanocytic nevus localized in the region of the waist band was excised because of mechanical irritation; it had not shown any changes over years. A thorough examination of the whole body did not give any clue to a malignant melanoma. Histologically a compound nevus with the typical architecture of a congenital melanocytic nevus was found. In the deeper dermis there was an isolated nodule of extremely atypical melanocytes with minimal pigmentation of melanin. S100 antigen could be demonstrated throughout the whole tumour whereas HMB45 was only found at the dermoepidermal junction. There was no marking of the tumour cells with a pancytokeratin antibody. A histological relationship between the new tumour and a mixed tumour of the left testicle, which had been excised 3 years ago, could be excluded. We did not find any metastases neither by image-aided methods nor by sentinel lymph node biopsy.     

Acquired unilateral melanocytic nevi in otherwise normal skin

We describe a case with numerous melanocytic nevi in otherwise normal skin. A 5-year-old girl presented with more than 100 small pigment lesions on her left arm, shoulder and upper back without underlying light brown macule. The pigment lesions were first found on her left forearm at 3 months old and gradually increased along with her growth. Skin biopsy from a pigmented lesion shows a pathological change in compound-type melanocytic nevus without any atypical changes. Speckled lentiginous nevus is known to have multiple melanocytic lesions on the underlying brown macule from birth. Partial unilateral lentiginosis is characterized by unilateral lentigines with histopathological changes in lentigo but not melanocytic proliferation in the dermis. Agminated melanocytic nevi tend to be clustered together in a circumscribed area, whereas in the present case melanocytic nevi were segmentally arranged but not agminated. We consider that this is an unusual type of mosaicism of melanocytic disorders.     

Superficial malignant peripheral nerve sheath tumor with overlying intradermal melanocytic nevus mimicking spindle cell melanoma

Malignant peripheral nerve sheath tumors are rare soft tissue sarcomas with histological and immunohistochemical similarities to spindle cell melanoma. Although spindle cell melanoma is significantly more common, both tumors may express S100 and lack staining for HMB‐45, Melan‐A or MITF. Here we present a case of superficial malignant peripheral nerve sheath tumor with diffuse S100 positivity arising in a subtle neurofibroma in close proximity to an intradermal melanocytic nevus. This configuration had led to prior misdiagnosis as a desmoplastic melanoma arising in the nevus and to sentinel lymph node biopsy. Identification of the background neurofibroma, as well as CD34 positivity raised consideration of a low grade malignant peripheral nerve sheath tumor, which was confirmed via observation of Schwannian differentiation on electron microscopy. The importance of distinguishing these two tumors is stressed owing to the difference in management.     

What sentinel node biopsy in patients with melanoma (or patients whose doctors worry that they could have melanoma) might and might not do

The sentinel lymph node biopsy has taught us important lessons about the behavior of melanoma and, perhaps, of melanocytic nevi. It is of proven prognostic importance in patients whose diagnosis of melanoma is clear-cut. Sentinel lymph node biopsy is an imperfect prognostic tool, however, and although the morbidity of the procedure is low, completion lymphadenectomy has a high morbidity rate and unproven benefit. In the setting of a borderline lesion, small nodal deposits must be interpreted with caution.     

Hair Matrix Differentiation in a Trichogenic Adnexal Neoplasm.

We have reviewed sixteen patients with the diagnosis of desmoplastic Spitz nevus. The age of our patients ranged between seven years and fifty‐four years. We noted a predominance of twelve female patients and four male patients. Histologically, ten of the sixteen cases were well circumscribed and symmetric. In six cases we were unable to ascertain the overall architectural features because of the biopsy technique. Only three cases showed significant junctional melanocytic nesting. In five cases there were rare nests of melanocytes at the dermo‐epidermal junction and in eight cases there was no evidence of melanocytic nesting at the dermo‐epidermal junction. Dermal mitotic figures were rare, with five cases showing a single dermal mitotic figure. The lesions did not arise in sun damaged skin as evidenced by the rarity of actinic elastosis within our specimens. Additional clinical and histologic findings and follow up will be reported.