Pseudomelanoma Research Articles

Treatment of Nevus Sebaceous with Short-term Photodynamic therapy combined with simple Surgery

SignificanceNevus sebaceous is a benign cutaneous hamartoma involving the epidermis, pilosebaceous units, and other adnexal structures. To avoid or minimize the scar, photodynamic therapy (PDT) is recommended as a non-surgical treatment. ApproachIn this report, we present a successful case of recurrent nevus sebaceous treated with a combination therapy of PDT and surgical excision. The patient was followed-up for a period of 6 months to evaluate the effectiveness of the treatment. ResultsThe patient underwent three sessions of PDT at three-week intervals, followed by surgical resection. Following the procedure, there was no recurrence of the lesion after 6 months, and the achieved a favorable cosmetic outcome. ConclusionsIn cases where the nevus sebaceous affects larger areas, employing a short-term PDT regimen in conjunction with surgical intervention proves to be an effective strategy, reducing the extent of surgical excision and yielding superior cosmetic results for our patients.

Recurrent nevus phenomenon from shave excision

Recurrent nevus phenomenon from shave excision

CLINICAL CASE OF RECURRENT NEVUS

Abstract. Introduction. Recurrent nevus is a benign proliferation of melanocytes that occurs at the site of non-radical removal of a previously existing nevus. Recurrence rates range from 0.3% to 28% and most often occur within 6 weeks to 6 months after removal. Clinically recurrent nevus is characterized by uneven pigmentation with uneven edges in the area of the scar.
 Walton et al. began researching the phenomenon of recurrent nevus in 1957. In 1975, Kornberg and Ackerman reported that a pigmented recurrent nevus can resemble superficially spreading melanoma both clinically and histologically, and proposed the term pseudomelanoma to describe this benign phenomenon. Currently, the term is rarely used, but it motivates a thorough examination of patients with such a problem.
 Case presentation. Patient A. complained about the presence of a formation in the area of the outer surface of the right forearm, which has existed for many years, it was injured several times, but has recently changed the colour. On examination, a nodule up to 0.5 cm in size, heterogeneously pigmented, with peripheral erythema was found in the indicated place. During dermoscopy, chaotic unevenly distributed pigmentation, consisting of dots, globules, forming a cellular structure in a scattered manner is determined, zones of segmental radial lines are present as well. The vascular pattern in the central part of the formation is not defined, on the periphery it is represented by slightly noticeable point vessels. Digital post-processing using machine learning technology was carried out to improve visualization of blood supply. Multiple point, curved, and convoluted vessels with few branches around the formation, and several central vessels in the pigment cells are determined. Surgical removal of the tumor was performed with involvement of the erythema zone, taking into account the peculiarities of pigmentation and vascular pattern. The pathogistological structure is presented in the photomicrograph. The epidermis has a typical structure, with areas of slight acanthosis; hyperpigmentation of the basal layer is also observed. In the dermis, foci of brown pigment deposition, single lymphocytes, there are areas of intradermal lobular-horizontal fibrosis with angiomatosis and scattered lymphocytic infiltration. Taking into account the clinical data, there is a recurrence of a melanocytic nevus on the background of a skin scar (Recurrent neavus).
 Teaching point. Dermoscopy allows obtaining additional data for the differential diagnosis of recurrent nevus and recurrent melanoma. A recurrent nevus is characterized by relative symmetry of formation and a pattern of segmental radial lines. The formation is limited to the area of the scar and does not go beyond it. Also, in the case of recurrent melanoma, a continuous growth in dynamics and a later appearance of recurrence from the moment of intervention will be obvious.
 Conclusions. As clinical practice demonstrates, under certain circumstances, recurrent pigmentation can be observed in cases of nevi that have been traumatized. It will be visible both dermoscopically and pathohistologically. Sometimes it is difficult even for experts to distinguish between a highly irritated nevus and a melanoma.

Recognizing Histopathological Simulators of Melanoma to Avoid Misdiagnosis.

Melanocytic lesions have a wide morphological spectrum, ranging from benign nevi to malignant melanoma. In contrast to a diagnosis of a benign nevus, a diagnosis of melanoma could mean intensive treatment, lifetime monitoring, and a worse prognosis. Therefore, melanocytic tumors are notoriously challenging and associated with a high risk of litigation in surgical pathology. After describing the basic features of nevi and melanoma, this article describes the detailed clinical and histological features of those lesions that share many similar features with melanoma. The entities included are Spitz nevi and atypical Spitz tumors (AST), Reed nevus, dysplastic nevus, cellular blue nevus (CBN), deep penetrating nevus, combined nevus, recurrent nevus, irritated nevus, congenital pattern nevus, acral nevus, and nevi of special sites. Knowledge of these imitators can help pathologists distinguish between benign and malignant cases and avoid misdiagnosis.

TERT and TERT promoter in melanocytic neoplasms: Current concepts in pathogenesis, diagnosis, and prognosis.

Located on chromosome locus 5p15.33, telomerase reverse transcriptase (TERT or hTERT) encodes the catalytic subunit of telomerase which permits lengthening and preservation of telomeres following mitosis. Mutations in TERT promoter (TERT-p) upregulate expression of TERT, allowing survival of malignant cells and tumor progression in wide variety of malignancies including melanoma. The objective of this review is to examine the roles of TERT and TERT-p in the pathogenesis, diagnosis, and prognostication of cutaneous melanoma. All studies of TERT or TERT-p in cutaneous melanocytic neoplasms with the following inclusion criteria were reviewed: publication date between 2010 and 2019, English language, and series of ≥3 cases were reviewed for evidence supporting the role of TERT in pathogenesis, diagnosis, and prognosis. Studies with <3 cases or focused primarily on mucosal or uveal melanocytic tumors were excluded. TERT-p mutations are frequent in chronic and non-chronic sun damage melanoma and correlate with adverse prognosis, inform pathogenesis, and may provide diagnostic support. While TERT-p mutations are uncommon in acral melanoma, TERT copy number gains and gene amplification predict reduced survival. Among atypical spitzoid neoplasms, TERT-p mutations identify biologically aggressive tumors and support the diagnosis of spitzoid melanoma. TERT-p methylation may have prognostic value in pediatric conventional melanoma and drive tumorigenesis in melanoma arising within congenital nevi. Finally, TERT-p mutations may aid in the differentiation of recurrent nevi from recurrent melanoma.

Predictive Value of Positive Margins in Diagnostic Biopsies of Dysplastic Nevi.

Dysplastic nevi (DN) are common and controversial and the best choice for management of DN after diagnosis is not always clear. The presence of positive margins found on diagnostic biopsy is used by many dermatologists when deciding whether to re-excise these lesions. In order to quantify the predictive value of positive margins in diagnostic biopsies of DN, we performed a review and analysis of the concordance between the histological findings of biopsies and their subsequent excisions. A total of 122 pathology reports from diagnostic biopsies of DN with nevus cells present at the tissue margin were reviewed. Within this sample, 68 total postbiopsy excisions had been performed. The excisional pathology reports were reviewed for the presence of residual or recurrent nevus cells. Residual nevus cells were reported in 29 of 63 available excisional pathology reports illustrating a positive predictive value (PPV) of positive margins in diagnostic biopsies of DN of 46.0%. We present this value along with PPVs from the very few existing similar studies. The quantified predictive value of positive margins in diagnostic biopsies is useful information for providers who must make decisions regarding the best treatment options for patients with DN. The low PPV of positive margins lends further evidence that DN of moderate severity or less may simply be monitored.

Pearls and Updates in Dermatopathology for the General Surgical Pathologist: Experts Weigh In on What You Need to Know.

Pearls and Updates in Dermatopathology for the General Surgical Pathologist: Experts Weigh In on What You Need to Know.

Recurrent Nevus After Burn Injury.

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Pseudomelanoma (with Cataract) in a Child Caused by Amniocentesis

Pseudomelanoma (with Cataract) in a Child Caused by Amniocentesis

Clinical and dermoscopic (in vivo and ex vivo) predictors of recurrent nevi.

Recurrent nevi occur following removal of melanocytic nevi mainly after shaving excision. Due to its differential diagnosis with melanoma, its recognition can be challenging. To evaluate clinical and dermoscopic predictors of recurrent nevi. Clinical data on 224 melanocytic nevi were collected, together with dermoscopic images. Shave biopsy was performed and the underside of the surgical specimen was examined using ex vivo dermoscopy. A total of 195 lesions were followed for six months. Recurrent nevi were observed in 59 lesions. The occurrence of recurrent nevi was inversely associated with increased patient age. Darker skin phototypes and the compound nevus type were more associated with recurrence. Regarding dermoscopic features, the presence of dark brown colour, multiple colours, dots, terminal hair, and an annular-distributed pigmentation around adnexal structures were associated with recurrent nevi. Ex vivo dermoscopy showed that visible hyperpigmentation on the underside of the surgical specimen was correlated with recurrence. Multivariable analysis showed that annular hyperpigmentation and age were the most relevant predictors of recurrence. Individuals with dark skin type and young adults are at increased risk of recurrent nevi. Dermoscopy of the primary lesion and the underside of the surgical specimen are helpful in predicting recurrence after shave biopsy.

The role of TERT promoter mutations in differentiating recurrent nevi from recurrent melanomas: A retrospective, case-control study

Repigmentation at previous biopsy sites pose a significant diagnostic dilemma given clinical and histologic similarities between recurrent nevi and locally recurrent melanoma. Though common in melanoma, the role of TERT promoter mutations (TPMs) in recurrent nevi is unknown. We investigated the role of TPMs in recurrent nevi and whether the presence of hotspot TPM distinguishes recurrent nevi from locally recurrent melanoma. We also characterized clinical and histologic features differentiating these lesions. We analyzed 11 locally recurrent melanomas, 17 recurrent nevi, and melanoma and nevus controls to determine TPM status. We also assessed clinical and histologic features of the recurrent groups. Hotspot TPMs were more common in recurrent melanomas than recurrent nevi (P=.008). Recurrent melanomas were more likely to have solar elastosis (P=.0047), multilayering of melanocytes in the epidermis (P=.0221), adnexal involvement (P=.0069), and epidermal consumption (P=.0204). Recurrent nevi had intra-epidermal atypia limited to the area above the scar (P<.0001) and occurred earlier after the original biopsy (P<.0008). Solar elastosis, months to recurrence, and hotspot TPMs were independently associated with recurrent melanoma in multivariate analysis. This was a retrospective study. Hotspot TPMs are significantly more frequent in recurrent melanomas and could serve as a diagnostic clue in histologically ambiguous cases.

Une forme pagétoïde de pseudomélanome d’Ackerman secondaire à un naevus congénital dans l’enfance : à propos d’un cas

Recurrent nevus (RN) is a cutaneous benign tumour with similarities with malignant lesions. Typically, it occurs after a partial resection of commun-acquired nevus. Its incidence varies from 0.3to 27% according to the studies. We present here a pediatric case of a pagetoid form of a recurrent nevus occurring from a congenital nevus. A congenital nevus was removed from a 9-month-old girl. Pathologists concluded to a commun-acquired nevus of complete exeresis. Two other cutaneous lesions appeared and we decided to realise a total removal. Analysis showed a recurrent nevus with some atypical histological features. No recurrence has occurred during the three post-operative of follow-up. It is an interesting case because of the occurrence of a RN after the removal of a congenital nevus in a child. Furthermore, it displayed some atypical histological features. Practicians, such as surgeons, dermatologists or pathologists, have to be aware of the risk of misdiagnosis with this lesion, which presents some similarities with SSM melanoma. It would be interesting to determinate some markers to statuate about its benign feature. There is no management recommendation about this lesion but it seems to be necessary to remove it to eliminate a malignant tumour.

The limitations of dermoscopy: false-positive and false-negative tumours.

Dermoscopy has been documented to increase the diagnostic accuracy of clinicians evaluating skin tumours, improving their ability to detect skin cancer and better recognize benign moles. However, dermoscopically 'false-positive' and 'false-negative' tumours do exist. False-positive diagnosis usually leads to unnecessary excisions. False-negative diagnosis is much more dangerous, as it might result in overlooking a cancer, with severe undesirable consequences for the patient and the physician. Therefore, management strategies should mainly focus on addressing the risk of dermoscopically false-negative tumours. The most frequent benign tumours that might acquire dermatoscopic characteristics suggestive of malignancy are seborrhoeic keratosis (SK), including solar lentigo, melanoacanthoma, irritated, clonal and regressive SK, angioma (mainly thrombosed angioma and angiokeratoma), dermatofibroma, benign adnexal tumours and naevi (Clark, Spitz, recurrent, combined, sclerosing). The most useful clues to recognize these tumours are the following: solar lentigo - broad network; melanoacanthoma - sharp border; irritated SK - regularly distributed white perivascular halos; clonal SK - classic SK criteria; regressive SK - remnants of SK; targetoid haemosiderotic haemangioma - dark centre and reddish periphery; thrombosed angioma - sharp demarcation; angiokeratoma - dark lacunae; atypical dermatofibromas - palpation; follicular tumours - white colour; sebaceous tumours - yellow colour; Clark naevi - clinical context; Spitz/Reed naevi - age; combined naevi - blue central area; recurrent naevi - pigmentation within the scar; sclerosing naevi - age and location on the upper back; blue naevi - history. Malignant tumours that might mimic benign ones and escape detection are melanoma (insitu, nevoid, spitzoid, verrucous, regressive, amelanotic), squamous cell carcinoma (mainly well-differentiated variants) and rarely basal cell carcinoma (non-pigmented variants). The most useful clues to recognize the peculiar melanoma subtypes are as follows: melanoma insitu - irregular hyperpigmented areas; nevoid melanoma - history of growth; spitzoid melanoma - age; verrucous melanoma - blue-black sign; regressive melanoma - peppering or scar-like depigmentation; amelanotic melanoma - pink colour, linear irregular vessels, dotted vessels. In this article, we summarized the most frequent dermoscopic variations of common skin tumours that are often misinterpreted, aiming to assist clinicians to reduce the number of false diagnoses.

Recurrent nevus arising in a halo nevus: Dermoscopy and confocal microscopy features

Recurrent nevus arising in a halo nevus: Dermoscopy and confocal microscopy features

Recurrent nevi in graft following excision of giant congenital nevus

Recurrent nevi in graft following excision of giant congenital nevus

Atypical recurrent nevus mimicking an epidermolysis bullosa nevus in a patient with Hailey–Hailey disease (HHD)

Atypical recurrent nevus mimicking an epidermolysis bullosa nevus in a patient with Hailey–Hailey disease (HHD)

Recurrent Melanocytic Nevi and Melanomas in Dermoscopy

IMPORTANCE Differentiating recurrent nevi from recurrent melanoma is challenging. OBJECTIVE To determine dermoscopic features to differentiate recurrent nevi from melanomas. DESIGN, SETTING, AND PARTICIPANTS Retrospective observational study of 15 pigmented lesion clinics from 12 countries; 98 recurrent nevi (61.3%) and 62 recurrent melanomas (38.8%) were collected from January to December 2011. MAIN OUTCOMES AND MEASURES Scoring the dermoscopic features, patterns, and colors in correlation with the histopathologic findings. RESULTS In univariate analysis, radial lines, symmetry, and centrifugal growth pattern were significantly more common dermoscopically in recurrent nevi; in contrast, circles, especially if on the head and neck area, eccentric hyperpigmentation at the periphery, a chaotic and noncontinuous growth pattern, and pigmentation beyond the scar's edge were significantly more common in recurrent melanomas. Patients with recurrent melanomas were significantly older than patients with recurrent nevi (mean [SD] age, 63.1 [17.5] years vs 30.2 [12.4] years) (P<.001), and there was a significantly longer time interval between the first procedure and the second treatment (median time interval, 25 vs 8 months) (P<.001). In a multivariate analysis, pigmentation beyond the scar's edge (P=.002), age (P<.001), and anatomic site (P=.002) were significantly and independently associated with the diagnosis of recurrent melanoma in dermoscopy. CONCLUSIONS AND RELEVANCE Dermoscopically, pigmentation beyond the scar's edge is the strongest clue for melanoma. Dermoscopy is helpful in evaluating recurrent lesions, but final interpretation requires taking into account the patient age, anatomic site, time to recurrence, growth pattern, and, if available, the histopathologic findings of the first excision.

Melanocytic nevi with special features: clinical‐dermoscopic and reflectance confocal microscopic‐findings

Histopathology is considered the 'gold' standard for the diagnosis and classification of melanocytic nevi, but the widespread use of in vivo diagnostic technologies such as dermoscopy and reflectance confocal microscopy (RCM), has enriched profoundly the knowledge regarding the morphological variability in nevi. This is because most morphological observations made via these in vivo tools are closely correlated with features seen in histopathology. Dermoscopy has allowed for a more detailed classification of nevi. As such, dermoscopy identifies four main morphologic groups (i.e. globular, reticular, starburst and structureless blue nevi), one group of nevi located at special body sites (i.e. face, acral, nail) and one group of nevi with special features. This latter category consists of nevi of the former categories, which are typified by peculiar clinical-histopathological findings. They can be subdivided into 'melanoma simulators' including combined nevi, recurrent nevi and sclerosing nevus with pseudomelanomatous features, 'targetoid' nevi (i.e. halo, cockade, irritated targetoid haemosiderotic and eczematous nevus) and uncommon histopathological variants such as desmoplastic, white dysplastic or ballon cell nevus. While the dermoscopic and RCM patterns of the former categories have been studied in detail, little is currently known about the clinical morphology of the heterogeneous group of 'special' nevi. In this article, we describe the clinical, dermoscopic and RCM features of 'special' nevi and review the current literature on this group of melanocytic proliferations.

Pitfalls in the evaluation of melanocytic lesions

The pathology of melanocytic tumours remains one of the most challenging and controversial fields in diagnostic histopathology, and it is one of the leading causes for litigation against pathologists. This is due largely to the wide morphological spectrum and often only subtle differentiating features with potential for both under- as well as overdiagnosis of melanoma. Particular pitfalls include the diagnosis of rare and unusual melanoma variants and melanoma resembling naevi. Furthermore, a subset of benign naevi may show concerning features associated more typically with a diagnosis of melanoma. These features include irregular junctional components with pagetoid spread, melanocyte atypia, lack of dermal maturation, dermal mitotic activity, intense melanin pigmentation, a desmoplastic stromal response and dermal regression. This paper focuses on a selected group of benign melanocytic lesions that are notoriously difficult to diagnose, and includes halo naevi, recurrent naevi, mitotically active naevi, desmoplastic naevi, clonal and deep penetrating naevi as well as cellular and plaque type blue naevi. The clinical and histological presentation is discussed with emphasis on clues to the correct diagnosis and distinguishing features from melanoma. Awareness of these entities and their distinguishing clinical and morphological characteristics is essential, as they present major diagnostic pitfalls.

The Recurrent Nevus Phenomenon: A History of Challenge, Controversy, and Discovery

The diagnosis of recurrent nevus poses a potential challenge to practicing pathologists. Although most recurrent nevi show uniform microscopic findings and pose no great diagnostic difficulty, a few cases exhibit some histopathologic features similar to, and in some cases indistinguishable from, melanoma. Historically, the term pseudomelanoma has been used in the literature to describe such recurrent nevi, although this label has the potential for confusion and is no longer the favored term for recurrent pigmented melanocytic nevi. To describe historical, histopathologic, and immunohistochemical features of recurrent pigmented melanocytic nevi and to review briefly the literature surrounding the mechanism of recurrence. Published peer-reviewed literature and the authors' personal experience. Recognition of the histopathologic pattern of recurrent nevi leads the pathologist to the correct diagnosis in most cases; however, in particularly challenging specimens or in circumstances in which there is insufficient clinical history, immunohistochemical studies have proved helpful in distinguishing recurrent nevi from melanoma.