Pagetoid melanocytosis: when is it significant?

Paget cells of the esophagus: A clinicopathologic and immunohistochemical study of 10 cases

OBJECTIVES

Extramammary Paget's disease (EMPD) of the esophagus is very rare and the clinicopathologic features are not well characterized.

DESIGN

We analyzed 10 cases with reported presence of Paget or Pagetoid tumor cells in the esophageal specimens collected between 2005 and 2018 at our institution.

RESULTS

The cohort included 7 males and 3 females with a median age of 67 years. Histologically, 7 cases were secondary Pagetoid spread of tumor cells directly from an underlying invasive adenocarcinoma (pADC) located at the distal esophagus, all CK7 + with variable intracytoplasmic mucin. The clinical course of those secondary cases was dependent on the underlying malignancies. Only 3 cases were primary, including 2 Pagetoid squamous cell carcinoma in-situ (pSqCCis) and 1 Pagetoid adenocarcinoma in-situ (pADCis) with focalstromal invasion. The primary cases showed similar clinical and endoscopic presentations. Immunohistochemically, the singly dispersed Paget or Pagetoid tumor cells frequently showed loss of E-cadherin and gain of vimentin expression. Seven cases, including 5 pADC, 1 pSqCCis and the pADCis showed aberrant p53 expression. Four patients, all pADC, died of disease at a median follow-up of 10 months, while the others were alive.

CONCLUSIONS

Paget or Pagetoid tumor cells in the esophagus can be primary or secondary to an invasive carcinoma. The clinical outcomes depend on the underlying malignancy and extensiveness of disease. Frequent p53 aberrancies and epithelium-mesenchymal transition likely play a role in the pathogenesis.

Dysplastic nevus part I: Historical perspective, classification, and epidemiology

Since the late 1970s, the diagnosis and management of dysplastic nevi have been areas fraught with controversy in the fields of dermatology and dermatopathology. Diagnostic uncertainty and lack of standardized nomenclature continue to propagate confusion among clinicians, dermatopathologists, and patients. In part I of this CME review article, we summarize the historical context that gave rise to the debate surrounding dysplastic nevi and review key features for diagnosis, classification, and management, as well as epidemiology. We discuss essentials of clinical criteria, dermoscopic features, histopathologic features, and the diagnostic utility of total body photography and reflectance confocal microscopy in evaluating dysplastic nevi, with emphasis on information available since the last comprehensive review a decade ago.

Melanocytic Nevi with Site-related Atypia: A Case Series and Characterization of their Immunohistochemical Profile

BACKGROUND

Nevi of special sites (NOSS) are benign melanocytic lesions that occur at particular sites. Although the histological features of NOSS have been described, their immunophenotypic features have not been fully characterized.

AIMS

To present the clinicopathological characteristics of a case series of NOSS and to characterize their immunohistochemical profile.

MATERIALS AND METHODS

Thirty-five NOSS were assessed using immunoperoxidase staining techniques for the melanocytic (S100, Melan-A, and HMB45) and proliferation (Ki-67) markers RESULTS: All of the cases of NOSS showed concerning architectural changes (prominent lentiginous melanocytic proliferation, irregularities, crowdedness, and dyhesiveness of the nests), and cytological atypia (large nevomelanocytes with vesicular nuclei, clear cytoplasm, and dusty melanin pigment) that can lead to a misdiagnosis of atypical nevi or even melanomas. All of the cases of NOSS showed diffuse expression of S100 and Melan-A proteins. Ki-67 labeling index of the nevomelanocytes was extremely low. HMB45 protein expression was limited to the junctional and superficial dermal nevomelanocytes.

CONCLUSIONS

NOSS can show histological features that can easily mimic atypical nevi or melanomas and this diagnostic consideration should be kept in mind to avoid their misdiagnosis. The expression of HMB45 protein in NOSS indicates that their nevomelanocytic cells have an activated phenotype. The decreased HMB45 protein expression following a gradient from junctional to deeper dermal localization in NOSS is indicative of their immunohistochemical maturation.

Clinical and histopathological features of pagetoid Spitz nevi of the thigh

BACKGROUND

Pagetoid Spitz nevus is a rare subtype of Spitz nevus usually found on the lower extremities, particularly on the thigh of women. As a rare and under-recognized entity that can be misdiagnosed as melanoma, further characterization of clinical and histopathological features is needed to improve its recognition.

METHODS

A retrospective analysis of all melanocytic neoplasms from the thigh diagnosed over a 3-year period.

RESULTS

Fifty-five (15.4%) of the 357 melanocytic neoplasms on the thigh were Spitz nevi, the majority of them occurring in women (87.3%). Of the 55 Spitz nevi, 33 (60.0%) were pagetoid Spitz nevi, 14 (25.5%) were Reed nevi, and eight (14.5%) were conventional Spitz nevi. The mean age of patients with pagetoid Spitz nevi was 47.2, the majority being women (84.9%). Pagetoid Spitz nevi were small, with a mean histopathologic diameter of 4 mm, and often junctional (63.6%). Compared to Clark nevi of the thigh, pagetoid Spitz nevi comprised significantly more solitary melanocytes with a greater degree of scatter.

CONCLUSIONS

These results suggest that Spitz nevi and, in particular, pagetoid Spitz nevi constitute a significant percentage of nevi on the thigh. Previously reported benign clinical and histopathological features of pagetoid Spitz nevi are confirmed in this study.

A Practical Approach to the Diagnosis of Melanocytic Lesions

CONTEXT.—

Melanocytic lesions are common in routine surgical pathology. Although the majority of these lesions can be confidently diagnosed using well-established morphologic criteria, there is a significant subset of lesions that can be diagnostically difficult. These can be a source of anxiety for patients, clinicians, and pathologists, and the potential consequences of a missed diagnosis of melanoma are serious.

OBJECTIVE.—

To provide a practical approach to the diagnosis of melanocytic lesions, including classic problem areas as well as suggestions for common challenges and appropriate incorporation of ancillary molecular techniques.

DATA SOURCES.—

Literature search using PubMed and Google Scholar, incorporating numerous search terms relevant to the particular section, combined with contemporaneous texts and lessons from personal experience.

CONCLUSIONS.—

Although a subset of melanocytic lesions can be diagnostically challenging, the combination of a methodical approach to histologic assessment, knowledge of potential diagnostic pitfalls, opinions from trusted colleagues, and judicious use of ancillary techniques can help the pathologist navigate this difficult area.

Langerhans cells and melanocytes share similar morphologic features under in vivo reflectance confocal microscopy: a challenge for melanoma diagnosis

BACKGROUND

Intraepidermal Langerhans cells (ILC) are difficult to differentiate from melanocytes under reflectance confocal microscopy (RCM) and their presence may simulate pagetoid spread of melanocytes on RCM images.

OBJECTIVE

We sought to correlate bright round and dendritic cells in a pagetoid pattern identified on RCM with findings of conventional histopathology and immunohistochemistry for lesions that were falsely diagnosed as melanoma by RCM.

METHODS

This retrospective study included histopathologically proven nevi, imaged by RCM, which displayed bright cells in a pagetoid pattern (BCPP) under RCM, resulting in the incorrect RCM diagnosis of melanoma. Morphological comparisons were made between RCM images of nevi showing BCPP, histopathologically proven melanomas displaying BCPP, and biopsy-proven nevi without BCPP.

RESULTS

We identified 24 nevi that were falsely diagnosed as melanoma by RCM because of the presence of BCPP. These pagetoid cells on RCM corresponded on histopathology to ILC with a high density in 23 of the 24 nevi (95%) and to melanocytes in 7 of the 24 nevi (29%). Among 6 melanomas displaying BCPP on RCM, ILC with high density were observed histopathologically in 5 of the 6 cases (83%) and pagetoid melanocytes were seen in all 6 cases (100%).

LIMITATIONS

The results cannot be generalized to clinically banal-appearing nevi.

CONCLUSIONS

Although the finding of BCPP is a useful RCM feature for the diagnosis of melanoma, it does not always imply the presence of pagetoid melanocytes but may at times represent ILC.

Intraoral Spitz naevus: a case report

Intraoral occurrences of Spitz naevus are very rare, there being only one previously documented case in the literature. Here is reported a case of a young male who presented with a pigmented lesion of the upper labial mucosa which had the clinical appearance of a simple naevus. Excision biopsy confirmed this to be a Spitz naevus. This lesion shares histopathological similarities with malignant melanoma. Spitz naevus is a benign lesion, but malignant transformation has been reported and close monitoring is recommended.

Cutaneous melanoma arising in a burn scar: two recent cases and a review of the literature

Melanoma arising in a burn scar is extremely uncommon. We report two recent cases, including one patient in whom six distinct primary melanomas arose in the setting of an extensive truncal burn scar. Only 27 patients have been reported previously, and only three previous cases of multiple primary melanomas arising in a burn scar have been described.