Spitz nevus (large spindle cell and/or epithelioid cell nevus). Age-related involvement of the suprabasal epidermis

Genomic Landscape of Spitzoid Neoplasms Impacting Patient Management

Spitzoid neoplasms are a distinct group of melanocytic proliferations characterized by epithelioid and/ or spindle shaped melanocytes. Intermediate forms that share features of both benign Spitz nevi (SN) and Spitz melanoma, i.e., malignant Spitz tumor (MST) represent a diagnostically and clinically challenging group of melanocytic lesions. A multitude of descriptive diagnostic terms exist for these ambiguous lesions with atypical Spitz tumor (AST) or Spitz tumor of uncertain malignant potential (STUMP) just naming two of them. This diagnostic gray zone creates confusion and high insecurity in clinicians and in patients. Biological behavior and clinical course of this intermediate group still remains largely unknown, often leading to difficulties with uncertainties in clinical management and prognosis. Consequently, a better stratification of Spitzoid neoplasms in benign and malignant forms is required thereby keeping the diagnostic group of AST/STUMP as small as possible. Ancillary diagnostic techniques such as immunohistochemistry, comparative genomic hybridization, fluorescence in situ hybridization, next generation sequencing, micro RNA and mRNA analysis as well as mass spectrometry imaging offer new opportunities for the distinct diagnosis, thereby allowing the best clinical management of Spitzoid neoplasms. This review gives an overview on these additional diagnostic techniques and the recent developments in the field of molecular genetic alterations in Spitzoid neoplasms. We also discuss how the recent findings might facilitate the diagnosis and stratification of atypical Spitzoid neoplasms and how these findings will impact the diagnostic work up as well as patient management. We suggest a stepwise implementation of ancillary diagnostic techniques thereby integrating immunohistochemistry and molecular pathology findings in the diagnosis of challenging ambiguous Spitzoid neoplasms. Finally, we will give an outlook on pending future research objectives in the field of Spitzoid melanocytic lesions.

Spitz nevus on the sole of the foot presenting with transepidermal elimination

A 10-year-old Japanese girl presented with a rhomboid-shaped brown macule, 4x3 mm in size, on the sole of the right foot. Dermoscopic examination revealed a number of black dots and globules on the ridges of the skin, marking an area of symmetrical brown pigmentation. On the periphery, a streak-like arrangement of black dots/globules on the brown pigmentation was observed along the ridges, simulating a “starburst” pattern. The lesion was excised and histological examination showed a symmetrical wedge-shaped compound melanocytic lesion that consisted of junctional and intradermal nests of a mixture of large spindle and epithelioid cells. None of the cells were atypical, and maturation of the cells with increasing depth was observed. From these findings, a diagnosis of Spitz nevus was made. Transepidermal elimination of nevus cell nests was observed and there were small groups of degenerated melanin-laden cells in the cornified layer. Masson Fontana stain revealed fine melanin deposits in the nevus cells of the junctional and intradermal nests, as well as heavy melanin deposits in the small groups of degenerated cells in the cornified layer. The distribution of melanin may contribute to a unique dermoscopic finding in this case.

Using dermoscopic criteria and patient-related factors for the management of pigmented melanocytic nevi

OBJECTIVE

To review recent dermoscopy studies that provide new insights into the evolution of nevi and their patterns of pigmentation as they contribute to the diagnosis of nevi and the management of pigmented melanocytic nevi.

DATA SOURCES

Data for this article were identified by searching the English and German literature by Medline and Journals@Ovid search for the period 1950 to January 2009.

STUDY SELECTION

The following relevant terms were used: dermoscopy, dermatoscopy, epiluminescence microscopy (ELM), surface microscopy, digital dermoscopy, digital dermatoscopy, digital epiluminescence microscopy, digital surface microscopy, melanocytic skin lesion, nevi, and pigmented skin lesions. There were no exclusion criteria.

DATA SYNTHESIS

The dermoscopic diagnosis of nevi relies on the following 4 criteria (each of which is characterized by 4 variables): (1) color (black, brown, gray, and blue); (2) pattern (globular, reticular, starburst, and homogeneous blue pattern); (3) pigment distribution (multifocal, central, eccentric, and uniform); and (4) special sites (face, acral areas, nail, and mucosa). In addition, the following 6 factors related to the patient might influence the pattern of pigmentation of the individual nevi: age, skin type, history of melanoma, UV exposure, pregnancy, and growth dynamics.

CONCLUSIONS

The 4 x 4 x 6 "rule" may help clinicians remember the basic dermoscopic criteria of nevi and the patient-related factors influencing their patterns. Dermoscopy is a useful technique for diagnosing melanocytic nevi, but the clinician should take additional factors into consideration to optimize the management of cases of pigmented lesions.

Spitz nevus: a clinicopathological study of 349 cases

Spitz nevus is an infrequent, usually acquired melanocytic nevus composed of epithelioid and/or spindle melanocytes that can occasionally be confused with melanoma. Currently, there are no immunohistochemical markers or molecular biology techniques that can be used to make an entirely safe diagnosis of Spitz nevus or melanoma in problematic cases. A retrospective study has been carried out that included all the cases diagnosed as Spitz nevus from our files. Follow-up information of the patients was unavailable. Three hundred forty-nine cases of unequivocal Spitz nevi were included, and their clinical and histopathological parameters were reviewed. One hundred and forty patients (40%) were 15 years old or younger, with a male to female ratio of 1:1. In patients older than 15 years, there was an evident predominance of women, with a male to female ratio of around 1:3. Spitz nevus was most commonly located on the lower extremities, followed by the trunk in both children and adults. Despite the fact that the head and neck were the third most common location in children, it was a much more frequent location in children than in adults. The constitution by epithelioid and/or spindled cells was the only histopathological finding present in 100% of cases. The other pathological findings studied were, from more to less frequent: maturation (72%), inflammatory infiltrate (70%), epidermal hyperplasia (66%), melanin (50%), telangiectasias (40%), Kamino bodies (34%), desmoplastic stroma (26%), mitosis (23%), pagetoid extension (13%), and hyalinization of the stroma (8%). Hyalinization was the only histopathological parameter that was statistically more frequent in adults than in children.

Spitz nevus is relatively frequent in adults: a clinico-pathologic study of 247 cases related to patient's age

Spitz nevus is a clinico-pathologic entity that can cause diagnostic concern, particularly in adults. Many studies have been performed to establish reliable histologic criteria, in the attempt to differentiate this lesion from melanoma. A series of 247 Spitz nevi, 6 of which were formerly classified as melanomas, were reviewed for clinical and histopathological parameters. Patients older than 20 comprised 66% of cases, with a predominance of women. The lower extremity was more affected in females of any age, whereas the trunk was more frequently involved in men over 40. Histopathologic examination showed the following differences among Spitz nevi related to age: acanthosis, parakeratosis, pagetoid infiltration, and Kamino bodies were more frequent in young people, whereas multinucleated melanocytes were more frequent in adults. The latter also had lesions that were less pigmented, with less maturation and more desmoplasia. At a mean follow-up of 94 months (range 52-172), recurrence at the site of biopsy or metastases were absent. In our study, a greater proportion of Spitz nevi occurred in adults than in previous series. Moreover, the relative incidence of Spitz nevus compared with melanoma in our population was higher than in other studies. Histopathologic criteria elaborated to diagnose Spitz nevus, applied to our cases, appeared reliable, allowing a correct diagnosis, even in adults.

The Spitzoid lesion: rethinking Spitz tumors, atypical variants, 'Spitzoid melanoma' and risk assessment

Although much remains to be learned about Spitzoid lesions, there is increasing evidence that these tumors may be a type of melanocytic neoplasm distinct from conventional melanocytic nevi and malignant melanoma. In the current communication, the author has attempted to describe accurately the state-of-the-art surrounding these lesions, their nomenclature, and assessment of risk. Acknowledging the peculiar nature of Spitzoid lesions, the author prefers the term Spitz tumor rather than 'Spitz nevus' (except perhaps for the most typical lesions) and argues against using the term 'Spitzoid melanoma' until more information is available to justify such a term. The author also believes that patients are best served by the comprehensive evaluation of Spitzoid lesions and their classification into three categories: (1) Spitz tumor without significant abnormality, (2) Spitz tumor with one or more atypical features (atypical Spitz tumor), including those judged to have indeterminate biological potential, and (3) malignant melanoma, rather than the two categories of 'Spitz nevus' and melanoma. Only rigorous characterization of sufficient numbers of Spitzoid lesions and long-term follow-up of patients will provide truly objective information for the formulation of optimal guidelines for the management of patients with these lesions.

Spitz nevus and its histologic simulators

Spitz nevi continue to pose a considerable diagnostic challenge to the histopathologist. Key features of Spitz nevus and its variants are discussed and contrasted with the telltale signs of malignancy of "Spitzoid" melanomas. The importance of the histologic features of the deep, rather than superficial, part of the lesions is emphasized.

Plexiform spitz nevus: an intradermal spitz nevus with plexiform growth pattern

Two cases of a distinctive variant of Spitz (spindle and epithelioid cell) nevus are described. One lesion developed on the lower leg of a 17-year-old boy and the other lesion on the back of a 52-year-old man. The microscopic appearance was characterized by a plexiform arrangement of bundles and lobules of enlarged spindle to epithelioid melanocytes throughout the superficial and deep dermis. Intraepidermal melanocytic proliferation was unappreciated. Some lobules were circumscribed by a thin rim of compressed fibrous tissue. In both cases a myxoid stroma was present. The cells had abundant eosinophilic cytoplasm with well-defined borders. The nuclei were enlarged, consistently ovoid and vesicular, with small nucleoli. Both cases contained scattered multinucleate giant cells similar to those observed in classical form of Spitz nevi. No melanin pigment was detectable by light microscopy. No mitoses were observed in one case and a rare mitosis was present in the other. Tumor cells were strongly immunoreactive for S-100, but not for HMB-45, desmin, and actin. The differential diagnosis of this distinctive tumor includes desmoplastic/neurotropic melanoma, plexiform spindle cell nevus, cellular blue nevus, plexiform neurofibroma, and cellular neurothekeoma. The designation of "plexiform Spitz nevus" is chosen to emphasize its distinctive plexiform growth pattern.

Perforating lichen nitidus

A 32-year-old man with no particular family history nor past history visited our clinic in September 1992, with papules that he claimed had developed approximately 3 years earlier. No subjective symptoms accompanied then. On examination, numerous, discrete, pinhead-sized or half-ricecorn-sized, flesh-colored papules were observed on the dorsolateral side of his left hand and fingers. No central dimple or scaling were noticed clinically (Fig. 1). Laboratory tests revealed no abnormal findings. The histopathology of the biopsied specimen showed a circumscribed nest of infiltrating cells closely attached to the epidermis (Fig. 2). These infiltrating cells consisted of mononuclear lymphoid cells and histiocytes. The overlying epidermis was stretched and atrophic. A transepithelial perforation channel existed in direct contact with the surface. Amorphous debris containing cell nuclei lay within the channel (Fig. 2). Lymphoid cells were also observed above the keratin layer overlying the channel. At the lateral margin of the infiltrate, rete ridges extended downward in the manner of a claw clutching a ball. In a periodic-acid-Schiff (PAS)-stained section, a basement defect was observed around the channel.

Spitz nevus

BACKGROUND

The Spitz nevus is a rare form of benign nevus, which may be confused with malignant melanoma.

METHODS

We reviewed the clinical and histologic features of 29 cases of Spitz nevus, of which 20 were dealt with by our department of dermatology at the Hull Royal Infirmary between 1969 and 1990. The other nine cases were from the records of our pathology department dated between 1979 and 1991, of which seven of the lesions were excised by the surgeons and two by the general practitioners.

RESULTS

In all the cases, the final diagnosis was established histologically. In three cases, there were difficulties histologically in excluding the diagnosis of malignant melanoma. All the lesions were solitary, and none of the lesions recurred following excision despite the possibility of incomplete excision in some cases.

CONCLUSIONS

We found the size of the lesion and the age of the patient important factors to consider in the diagnosis of Spitz nevus. The small number of cases we encountered over a period of 22 years in a department that serves a population of around 500,000 emphasises the rarity of the condition.

Spitz nevi

The Spitz nevus has long been defined as a benign melanocytic lesion that shares many histologic features with malignant melanoma. Despite the diagnostic criteria established for these two entities, their histologic similarities continue to make their distinction somewhat difficult. Uncertainties also exist with regard to the natural history of the Spitz nevus; the true pattern of this lesion's biologic behavior remains elusive. As a result, controversies exist with respect to appropriate therapy. To examine these controversies, the epidemiology, clinical features, and histopathology of Spitz nevi, as well as the role of recent molecular and immunohistochemical diagnostic studies, are discussed. However, the primary focus of this article is the natural course, prognosis, and treatment of the Spitz nevus. A review of 716 cases of Spitz nevi, compiled from 13 papers published from 1948 to 1990, is presented. After analyzing this and other available data, we propose that at this time Spitz nevi and malignant melanoma cannot easily be categorized as distinct entities and that perhaps they actually exist along one continuum of disease. Because of this uncertainty and the difficulties in differentiating these two lesions, we recommend that treatment include complete excision of all Spitz nevi followed by reexcision of positive margins if present.

Malignant melanoma in childhood: a clinicopathologic study of 13 cases and comparison with Spitz nevi

The clinical and histological features of 13 malignant melanomas in children less than 13 years of age in New South Wales, Australia, were compared with those in a control group of children with 15 Spitz nevi, 4 of which were considered atypical, and 2 unusual compound nevocellular nevi. Six of the controls had been previously diagnosed histologically as malignant melanoma. The objective observations made by one or more histopathologists experienced in reporting melanocytic lesions, and the clinical details, mainly from the Sydney Melanoma Unit files, were entered on a detailed protocol. Evaluation was assisted by the use of SPSS-X software on a mainframe VAX computer. Six of the 13 children with malignant melanoma died with their disease. The most frequent clinical features found in the malignant melanomas were bleeding, ulceration, itching, and black or variegated color. Recent enlargement and darkening were noted in the majority of both the malignant melanomas and the Spitz nevi. Histological features favoring malignancy in this series were mitoses within 0.25 mm of the dermal margin of the melanoma, a dermal mitotic rate exceeding 2/mm2, ulceration, surface exudate, large pigment granules, and clear-cell differentiation. The median thickness of the malignant melanomas was 1.3 mm but in the 4 children who died with melanoma the median thickness was 2.9 mm. Absence of mitoses, predominance of spindle cells, and diffuse maturation favored Spitz nevus. The median thickness of the Spitz nevi was 0.7 mm.

Histopathologic diagnosis of pigmented lesions of the skin

The present review deals with the histopathologic diagnosis of the commonest pigmented lesions of the skin with emphasis on melanocytic tumors. The discussed entities are systematized in pigmented lesions with and without an increase in the number of melanocytes, i.e. melanocytic hyperplasia, and in those that actually are melanocytic neoplasias. Histopathological, ultrastructural, and immunohistochemical features of relevance for the differential diagnosis are discussed in depth. One section is dedicated to the immunohistochemical markers of melanocytic lesions, the other one to the electron microscopy of malignant melanoma. Neoplasms simulating malignant melanoma and the less frequent variants of this tumor are also discussed. The diagnosis of pigmented lesions of the skin represents one of the most frequent and difficult challenges in dermatopathology, and useful clues for the differential diagnosis, especially of melanocytic dysplasias and neoplasias, are presented in the present article.

Intradermal Spitz nevus differentiated from reticulohistiocytic granuloma by immunoreactivity to S-100 protein

A firm, dark reddish, smooth surfaced nodule on the forearm of a 16-year-old boy was diagnosed as a Spitz nevus with the aid of a strong positive reactivity to S-100 protein. Histological examination revealed an intradermal epithelioid cell tumor with prominent multinucleated giant cells, suggesting the diagnosis of reticulohistiocytic granuloma. However, immunoperoxidase staining of the tumor cells showed strong positive reactivity to S-100 protein and vimentin; it was negative for lysozyme and alpha-1 antitrypsin. Although a few melanosomes in the tumor cells seen in electron microscopic examination provided crucial proof for the diagnosis of Spitz nevus, the positive reactivity to S-100 protein in ordinary formalin-fixed, paraffin-embedded tissues proved to be very useful in the differentiation of Spitz nevus from tumors of histiocytic origin, especially those of the mononuclear phagocytic system.