Desmoplastic melanocytic nevi with lymphocytic aggregates

Desmoplastic melanocytic nevi can be difficult to distinguish from desmoplastic melanoma. The presence of lymphocytic aggregates in association with a sclerosing melanocytic proliferation is commonly regarded as a feature in support of a diagnosis of desmoplastic melanoma. However, the finding is not specific for melanoma. Herein we report six cases of sclerosing melanocytic nevi with associated lymphocytic aggregates. They occurred in five women and one man, ranging in age from 11 to 61 years. Three lesions were sclerosing Spitz nevi; one was an amelanotic sclerosing blue nevus, one an acquired intradermal sclerosing nevus, and one was a congenital compound melanocytic nevus with sclerosis of its dermal component. The lesions were interpreted as benign, i.e. melanocytic nevi, because of their histopathologic attributes (symmetric silhouette, benign cytologic features) and results from immunohistochemical studies (all lesions strongly expressed Melan-A and p16) and fluorescence in situ hybridization (FISH). Three lesions tested by FISH lacked copy number changes of 11p, 6q or 6p. None of the lesions recurred. The cases highlight that contextual information is essential for the diagnosis of desmoplastic melanoma and sclerosing nevus. The presence of lymphocytic aggregates per se does not prove that a sclerosing melanocytic proliferation is malignant.     

Spitz nevus: a case report and the use of dermoscopy

The Spitz nevus is a benign melanocytic lesion with clinical and histopathological features similar to those of melanoma. It was first described in 1948 but great controversy still remains today with respect to its diagnosis and management. The use of dermoscopy may increase diagnostic accuracy. In Spitz nevus, the most common dermoscopic finding is a starburst-like pattern, followed by globular and atypical patterns. Diagnosis must be confirmed by histopathology, particularly in atypical cases.     

足跖和阴茎Spitz痣

报告2例发生在跖部和阴茎的Spitz痣。1例患者皮损位于阴茎，另1例位于跖部，其中位于跖部的Spitz痣需要和黑素瘤相鉴别。     

Classic and atypical Spitz nevi: review of the literature

Both classic and atypical Spitz nevi are uncommon melanocytic lesions usually presenting in children and adolescents. The classic Spitz nevus typically is benign and has characteristic clinical and histologic features. In contrast, the atypical Spitz nevus has an unknown clinical prognosis, and its clinical and histologic traits are loosely defined. Melanoma can have similar features to both classic and atypical Spitz nevi and must be ruled out in all cases. We review the literature on classic and atypical Spitz nevi, advances in differentiating both types of nevi from melanoma, and treatment options.     

Proliferation, apoptosis, and survivin expression in a spectrum of melanocytic nevi

BACKGROUND: Apoptosis is important for maintenance of tissue homeostasis and often dysregulated in cutaneous neoplasms. The apoptosis inhibitor survivin is expressed in melanoma and non-melanoma skin cancers and benign keratinocytic lesions. Its expression has not been studied in melanocytic nevi. OBJECTIVE: We determined the expression pattern of survivin in benign melanocytic nevi in comparison to markers of proliferation and apoptosis. METHODS: Six cases of each of the following melanocytic nevi were retrieved from a dermatopathology archive: compound dysplastic nevus, intradermal nevus, compound nevus, neurotized intradermal nevus, and Spitz nevus. Survivin expression was evaluated by in situ hybridization. Apoptotic and proliferation indices were calculated by counting immunoreactive cells in terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling and proliferating cell nuclear antigen immunostained sections, respectively. RESULTS: All nevi, regardless of histologic type, expressed survivin. Compound melanocytic lesions expressed survivin in both epidermal and dermal compartments. The apoptotic rate was low for dysplastic, compound, and Spitz nevi, and apoptotic cells were not identified in any neurotized nevus. The proliferative index was highest for Spitz nevi, while all other nevi demonstrated rare positive cells. CONCLUSIONS: Survivin is consistently expressed in benign melanocytic lesions, while apoptotic cells are rarely identified, suggesting the dysregulation of apoptotic pathways with the accumulation of cells in these neoplasms.     

斯皮茨痣16例临床及组织病理分析

目的：分析斯皮茨痣（Spitz nevus）的临床及组织病理特点。方法：采用回顾性分析对16例斯皮茨痣患者的临床及组织病理资料进行分析。结果：16例斯皮茨痣多发生于头面部和四肢,主要表现为黑色丘疹或斑疹,临床上容易误诊为色素痣。大部分斯皮茨痣具有良性肿瘤的特点,少数斯皮茨痣结构呈不对称性或细胞具有异形性,组织病理改变结合临床资料分析是诊断的关键。结论：表皮和附属器增生可作为斯皮茨痣与黑素瘤鉴别的依据之一,国人斯皮茨痣Kamino小体较少见。     

Application of fluorescence in situ hybridization as a diagnostic tool in melanocytic lesions,using paraffin wax‐embedded tissues and imprint‐cytology specimens

Background. Accurate histopathological diagnosis of certain melanocytic skin lesions as benign or malignant can be notoriously difficult. Recently, four‐colour fluorescence in situ hybridization (FISH) has emerged as an important tool for classifying these lesions. Aim. To evaluate the sensitivity and specificity of a melanoma FISH probe kit for accurate diagnosis of melanocytic tumours, and to validate its use with imprint‐cytology specimens from the cut surface of tumours. Methods. In total, 50 melanocytic skin lesions (31 malignant melanomas, 10 benign melanocytic naevi, and 9 histologically challenging benign melanocytic skin lesions) were evaluated. The samples comprise 47 tissue specimens embedded in paraffin wax, and three imprint‐cytology specimens from the cut surface of melanomas. FISH was performed using four locus‐specific identifier probes [Ras responsive element binding protein (RREB)1, myeloblastosis viral oncogene homologue (MYB), cyclin (CCN)D1 and centromere of chromosome (CEP)6], and results were compared with the clinical long‐term follow‐up and histopathological diagnosis data. Results. The melanoma FISH probe distinguished between naevi and melanomas with a sensitivity of 100% and a specificity of 94.1%. The most sensitive criterion was a gain in 6p25 (RREB1), seen in 100% of cases, followed by CEP6‐related MYB loss (48.1%), CCND1 gain (37%) and MYB gain (22.2%). More than three‐quarters (77.8%) of melanomas were positive for two or more criteria. Positive FISH results were also obtained for the imprint‐cytology specimens. Conclusions. FISH is a valuable diagnostic tool for differentiating between benign and malignant melanocytic lesions, providing a high degree of sensitivity and specificity. The probes displayed exceptional discriminative capacity in difficult or ambiguous lesions. To our knowledge, his is the first reported use of imprint‐cytology specimens for FISH diagnosis.     

Significant melanocytic lesions in infancy, childhood, and adolescence

Malignant melanoma is diagnosed yearly in approximately 300 persons under age 20 in the United States. Relatively recent advances in dermatology include the recognition of lesions felt to be potential precursors of malignant melanoma. Small congenital melanocytic nevi, present in 1 per cent of all newborn infants, may have a small but definite potential for developing malignant melanoma. Furthermore, despite inconclusive data, many leading dermatologists now advocate removal of these small congenital lesions. Giant congenital melanocytic nevi, with their strong predilection for undergoing malignant change, are removed surgically at an early age, often in multistaged procedures. Dermabrasion, once felt to have a role in the treatment of giant congenital nevi, does not remove the malignant potential of these lesions. The dysplastic nevus syndrome, recognized in 1976, identifies individuals at increased risk for developing melanoma. Adolescents who have the dysplastic nevus syndrome or who are members of families with the syndrome require close medical supervision and patient education. The benign Spitz nevus, with its histologic similarity to malignant melanoma, continues to challenge the dermatopathologist and clinician. These lesions--the Spitz nevus, dysplastic nevus, congenital melanocytic nevus, and malignant melanoma--must all be actively considered when regarding the many other benign melanocytic lesions found in infancy, childhood, and adolescence.     

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.     

BRCA1‐associated protein (BAP1)‐inactivated melanocytic tumors

Although discussed using variable terminology, cutaneous BRCA1‐associated protein (BAP1)‐inactivated melanocytic tumor (BIMT) has been considered a discrete diagnostic entity since 2011. Here, we review the initial genomic studies that identified these distinct melanocytic tumors and the clinical and histopathological features that define these tumors. These epithelioid, predominantly dermal, and melanocytic tumors present as erythematous nodules and histopathologically have features that may overlap with Spitz nevi and nevoid melanoma. There is no sex predilection, and cutaneous BIMTs can appear at any age; however, in most familial (germline mutant) cases patients have multiple cutaneous tumors with a first diagnosis in the second or third decade of life; ocular melanoma and other tumors are increasingly identified in these kindreds with germline BAP1 mutation. These tumors have been described with a myriad of terms including: Wiesner nevus, nevoid melanoma‐like melanocytic proliferation (NEMMP), BAP1 mutant Spitz nevus, BAP1 mutant nevoid melanoma, cutaneous BAPoma, and most recently cutaneous BIMT.     

Linear arrangement of multiple deep penetrating nevi: report of first case and review of literature

BACKGROUND: Deep penetrating nevus is a recently described variant of melanocytic nevi with clinical and histopathological features that may be confused with malignant melanoma, blue nevus, pigmented Spitz nevus, or congenital melanocytic nevus. We report a case with linear arrangement of multiple deep penetrating nevi. To our knowledge, such presentation has never been reported in the literature. OBSERVATIONS: We describe a patient with multiple darkly pigmented lesions in the right periauricular area, above and behind the ear. The histopathological features of these lesions were consistent with deep penetrating nevus. CONCLUSIONS: To our knowledge, this is the first report of linear arrangement of multiple deep penetrating nevi. We consider this case a unique presentation of deep penetrating nevus.     

Expression of c-kit (CD117) in Spitz nevus and malignant melanoma

BACKGROUND: CD117, the receptor for kit-ligand, which is a growth factor for melanocyte migration and proliferation, has shown differential staining in various benign and malignant melanocytic lesions. The purpose of this study is to compare CD117 immunohistological staining in Spitz nevus versus malignant melanoma, to determine whether CD117 can aid in the diagnosis of these two lesions. METHODS: CD-117 immunohistological staining was performed in 22 clinically and pathologically diagnosed pigmented lesions including 9 cases of Spitz nevus, 10 cases of primary MM and 3 cases of metastatic melanoma. RESULTS: There was no significant difference in CD117 staining in either epidermis or dermis between Spitz nevi and primary melanomas. However staining of metastatic melanomas is less than dermal staining of primary MM and Spitz nevus. CONCLUSIONS: CD117 is unlikely a useful diagnostic tool in differentiating Spitz nevus from primary MM. On the other hand, CD 117 may be useful in differentiating metastatic melanoma from primary melanoma in patients who had a history of melanoma and who present with new dermal lesions.     

Acral Pigmented Spitz Nevus That Clinically Mimicked Acral Lentiginous Malignant Melanoma

Pigmented Spitz nevus is a benign melanocytic skin lesion with distinct clinical features and it is frequently found on the extremities. However, it rarely occurs on acral area of the body, and such a case has not yet been fully documented. We present a case of acral pigmented Spitz nevus occurring on the foot, and this mimicked acral lentiginous malignant melanoma. Clinicians should be well aware of this entity and its possible clinical presentations. Since acral pigmented Spitz nevus is benign in nature, making the correct diagnosis is important to avoid unnecessary mutilating or excessive surgery.     

Immunohistochemical expression of cyclooxygenage-2 in melanocytic skin lesions

Background Several reports have shown expression of cyclooxygenase‐2 (COX‐2) in malignant skin tumors. COX‐2 has also recently been reported as a marker of malignant melanoma (MM). Objective Our aim was to investigate whether there is a difference in the immunohistochemical expression of COX‐2 between malignant and benign melanocytic lesions of the skin. Methods We selected 40 archival cases of MM including 10 cases of superficial spreading melanoma, 10 of lentigo maligna melanoma, 10 of nodular melanoma, and 10 of acral lentiginous melanoma. For comparison, we also selected 35 benign melanocytic lesions, which included 15 nonatypical nevi and 10 atypical nevi. The remaining 10 cases were Spitz nevi. COX‐2 immunohistochemical staining was performed, and intensities were assessed quantitatively. Results The MM group and the benign melanocytic nevi group showed a highly statistically significant difference in the intensity of COX‐2 expression (P < 0.0001). Staining intensity in the dermal component of MM cases also showed a tendency to increase with increasing tumor depth. By contrast, the intensity of the dermal component in the melanocytic nevi group decreased with increasing depth as the nevus cells matured from type A to type C cells. No statistical difference was noted between the MM and Spitz nevi cases (P = 0.20). Conclusions Malignant melanoma shows stronger immunohistochemical expression of COX‐2 than benign melanocytic nevi. Although COX‐2 cannot be used alone to differentiate MM from melanocytic nevi, it may serve as an aid in the differential diagnosis of melanocytic skin lesions.     

Spitz Nevi and Other Spitzoid Neoplasms in Children: Overview of Incidence Data and Diagnostic Criteria

Spitz nevi are benign melanocytic neoplasms characterized by epithelioid or spindle melanocytes or both. In some rare cases their presentation overlaps with the clinical and histopathologic features of malignant melanoma, so a differential diagnosis can be difficult to make. Intermediate forms between Spitz nevi and malignant melanoma, with unpredictable behavior, have been called atypical Spitz tumors. A literature search was performed to review the clinical, dermoscopic, genetic, and histopathologic aspects of spitzoid tumors. Spitz nevi mainly occur in children, with no predilection for sex, and in young women. Common sites are the head and lower arms, where Spitz nevi present as pink nodules or hyperpigmented plaques. Spitzoid lesions may have diverse dermoscopic patterns: vascular, starburst, globular, atypical, reticular, negative homogeneous, or targetoid. The management of spitzoid lesions can be invasive or conservative; surgical excision is usually reserved for those with doubtful features, whereas clinical and dermoscopic follow‐up is preferred for typical pediatric Spitz nevi. The role of sentinel lymph node biopsy in atypical Spitz tumors is debated. Immunohistochemistry and new molecular techniques such as comparative genomic hybridization, polymerase chain reaction, and fluorescence in situ hybridization offer new diagnostic perspectives, investigating genetic alterations that are specific for malignant melanoma or for Spitz nevi.     

Pseudogranulomatous Spitz nevus: a variant of Spitz nevus with heavy inflammatory infiltrate mimicking a granulomatous dermatitis

Spitz nevus is a benign melanocytic proliferation that shows relatively characteristic clinicopathologic features. Despite this, Spitz nevus is clinically confused with many other lesions, and histopathologically it is sometimes difficult to distinguish it from melanoma. However, Spitz nevus rarely causes differential diagnostic problems with granulomatous dermatitis. This article describes an 8‐year‐old girl who presented with a nodule on her right arm, a clinical appearance of a pyogenic granuloma. Histopathologically, there was a dermal lesion composed of aggregates of large epithelioid cells surrounded by a heavy inflammatory infiltrate, mimicking a sarcoid‐like granulomatous dermatitis. Immunohistochemistry showed epithelioid cells with strong nuclear and cytoplasmic staining with S‐100 protein, thus establishing the diagnosis of a melanocytic tumor. The heavy T‐cell lymphocytic infiltrate that accompanies the large epithelioid cells caused its granulomatous appearance. Molecular assessment showed H27H mutation in the HRAS gene. We suggest the term ‘pseudogranulomatous’ for this variant of Spitz nevus because it indicates that the lesion is not authentically granulomatous and simply mimics a granulomatous dermatitis.     

Spitz样肿瘤320例临床及组织病理分析

【摘要】 目的 总结Spitz样肿瘤的临床及组织病理特征。方法 回顾2005年1月至2020年1月西京皮肤医院确诊的320例Spitz样肿瘤患者的临床及病理资料。结果 320例患者中,男141例,女179例,年龄0 ~ 65（12.5 ± 11.7）岁,病程1个月至30年;其中,Spitz痣307例,不典型Spitz肿瘤（AST）8例,Spitz痣样黑素瘤（SM）5例。皮损多为单发,可见于头面部、躯干和四肢,边界均清楚。307例Spitz痣皮损以黑色（132例,43.0%）和红色（108例,35.1%）为主,多数色素均匀（262例,85.3%）且表面平滑（272例,88.6%）。Spitz痣存在特殊临床亚型,11例 （3.6%）发生在斑痣上,11例 （3.6%）呈簇发性,6例（2.0%）播散性,7例（2.3%）结节性,1例（0.3%）为瘢痕疙瘩样。Spitz痣特征性病理表现包括表皮内痣细胞呈Paget样扩散（123例,40.1%）,真表皮交界处出现Kamino小体（74例,24.1%）,痣细胞呈水平带状（177例,57.8%）及楔形分布（118例,38.4%）,痣细胞巢周围出现裂隙（177例,57.8%）,可见生理性核分裂象（117例,38.1%）,核染色质均细腻。根据特殊组织病理表现,Spitz痣又分为色素性上皮样Spitz痣（9例,2.9%）、结缔组织增生性Spitz痣（13例,4.2%）、血管瘤样Spitz痣（8例,2.6%）、疣状Spitz痣（12例,3.9%）、黏液样Spitz痣（10例,3.3%）、晕痣样Spitz痣（4例,1.3%） 等。4例AST皮损为黑色,7例色素均匀,3例皮损表面粗糙;特征病理表现包括细胞均有轻度至中度的异型性,均可见核分裂象（7例为2 ~ 6个/mm2）,5例核染色质粗糙。3例SM皮损呈红色,4例色素不均匀,3例表面粗糙;特征病理表现包括黑素细胞呈Paget样扩散（3例）,瘤细胞呈无极性浸润性生长且均未见成熟现象,均有明显异型性,并可见病理性核分裂象（3例, > 6个/mm2）,核染色质均粗糙且核膜明显着色。结论 Spitz样肿瘤的临床及组织病理表现具有特征性,Spitz痣的临床及病理亚型繁多,AST同时具有Spitz痣和黑素瘤的临床及组织学特征。     

Desmoplastic nevus: An entity distinct from spitz nevus and blue nevus

Desmoplastic (sclerotic) nevus is an infrequently reported poorly characterized benign melanocytic proliferation, with only 4 case series published to date. To better define this nevus, we examined the clinical and histologic features of 25 lesions. Desmoplastic nevus is seen in both children and adults and can be located on the face, trunk, or extremities. There is a female predominance. Clinically, it can resemble intradermal nevus, atypical nevus, melanoma, and pigmented basal cell carcinoma. These are generally small, symmetric, and well-circumscribed lesions, averaging 3.5 mm in diameter. The most distinctive features include predominantly compound growth, a zonal configuration with greater cellularity in the superficial portion of the lesion, and a mixture of melanocytic phenotypes including type A, B, and C nevus cells, ovoid and dendritic melanocytes, and Spitzoid melanocytes. A distinctive eosinophilic stroma which either resembles that of a dermatofibroma or neurofibroma is always present. Variable amounts of melanin pigment are found in both tumor cells and macrophages, but this is not a prominent feature. Mitotic activity is exceedingly rare (1 case), and pleomorphism is minimal. These lesions are distinct from typical compound nevus, Spitz nevus, epithelioid blue nevus, and desmoplastic melanoma, to which they are often compared. Strict application of these histologic features allows definitive diagnosis of desmoplastic nevus as a distinct form of a benign melanocytic nevus.