Clear-Cell Melanocytic Lesions With Balloon-Cell and Sebocyte-like Melanocytes: A Unifying Concept

Apocrine carcinoma with marked sebocyte-like cytological features: A report of two cases

Apocrine carcinoma cases with sebaceous differentiation have not been reported and can be misdiagnosed as sebaceous carcinoma. We present two cases of apocrine carcinoma with marked sebocyte-like cytological features. Tumors were observed in the left axilla of a 68-year-old man (Case 1) and the right axilla of a 72-year-old man (Case 2). Both patients presented with multiple lymph node metastases. Histopathology revealed densely distributed solid nests of tumor cells containing foamy cytoplasm and enlarged round nuclei with prominent nucleoli. The tumor cells diffusely expressed adipophilin, PRAME (cytoplasmic pattern), androgen receptor, BerEP4, and GCDFP15 but did not express p63 in both cases. PIK3CA E726K and H1047R mutations were detected in Cases 1 and 2, respectively. Tumor location in the axilla, the presence of eosinophilic granular cytoplasm, prominent nucleoli, and PIK3CA mutations, immunoreactivity for BerEP4 and GCDFP15, and lack of p63 immunoexpression findings matched apocrine carcinoma characteristics, but not sebaceous carcinoma. Thus, apocrine carcinoma can demonstrate intracytoplasmic lipid accumulation and rarely exhibit sebocyte-like cytological features. Apocrine carcinoma should be distinguished from sebaceous carcinoma due to the former's higher metastatic potential and lack of association with Muir-Torre syndrome.

Metastatic melanoma and rare melanoma variants: a review

The histopathological diagnosis of melanoma is fraught with potential pitfalls. In the setting of cutaneous metastatic melanoma, it is important to recognise the various histological patterns that can be encountered from the more common to the rare, including epidermotropic, folliculotropic, naevoid, and blue naevus-like. In addition, melanoma is notorious for phenotypic plasticity. Thus, there are many different subtypes and cytomorphological variations that can be difficult to recognise as melanoma, particularly in the recurrent or metastatic setting. Select melanoma variants including primary dermal, clear cell, plasmacytoid, signet ring cell, small cell, myxoid, rhabdoid, and dedifferentiated melanoma will be discussed, in addition to composite melanocytic neoplasms. This review is intended to remind the practitioner of key concepts of metastatic disease and select rare melanoma variants, while providing practical guidelines for accurate diagnosis.

A Rare Case of Primary Cutaneous Signet-Ring Cell Melanoma With Discrepant Findings on Gene Expression Profiling and Chromosomal Microarray Analysis

ABSTRACT

Melanoma with signet ring cell features is an exceptionally rare variant of primary cutaneous and metastatic melanoma. The molecular mechanisms underlying this unusual cytologic phenotype in malignant melanocytes are largely unknown. In this report, we aim to add to the literature by describing the histomorphological, immunophenotypic, gene expression, and cytogenetic findings in 1 recently encountered case.

Balloon Cell Melanoma: Presentation of Four Cases with a Comprehensive Review of the Literature

BACKGROUND

balloon cell melanoma represents less than 1% of all histological forms of malignant melanoma and represents a diagnostic challenge for the dermatopathologist.

METHODS

in this paper we present our cases of BCM found in our daily practice from 1 January 2008 to 31 December 2021, and we conduct a review of the literature relating to this entity in the period from the first description, 1970, to early 2022.

RESULTS

four cases of melanoma balloon cell have been extrapolated from our electronic database, while in the review of the literature we have identified 115 cases of patients with primary and/or metastatic BCM.

CONCLUSIONS

we believe that future studies with numerous case series are essential not only to increase the knowledge of the pathophysiology of this neoplasm but also to correctly evaluate the response of BCM patients to new oncological therapies.

Conjunctival Balloon Cell Nevus in a Young Child: A Case Report

Background:

Conjunctival balloon cell nevus is rare and often presents in young adults to middle-aged patients with a longstanding history of melanocytic lesion, suggestive of benign pathology. The main treatment modality is excisional biopsy. Tumor recurrence is very rare. Malignant transformation has never been reported.

Objective:

This study aimed to report a case of conjunctival balloon cell nevus with an atypical presentation in a preschooler.

Methods:

We describe a case of a 5-year-and-9-month-old girl who presented with a rapidly growing melanocytic conjunctival mass, which she had since birth. Ophthalmic examination showed two prominent feeder vessels, and the lesion straddled the limbus to overlie the peripheral part of the cornea. These findings raised an index of suspicion of malignant transformation. The lesion was completely excised with a 2-mm resection margin, superficial keratectomy, ethyl alcohol epitheliectomy, and cryotherapy.

Results and Discussion:

The histopathological examination and immunohistochemical study showed a compound conjunctival nevus of the conjunctiva with most of the cells as balloon cell type. There were no malignant changes found. Moreover, there were no signs of tumor recurrence at the last follow-up of 6 months.

Conclusion:

Clinically malignant characteristics have never been reported in balloon cell nevi in a preschooler of this age. Thorough physical examination, well-planned surgical procedure, and careful pathological examination all play vital roles in the management of patients with these lesions.

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Balloon cell nevus in children: Report of three cases of the scalp and review

Balloon cell nevus (BCN) is a histopathological variant of cutaneous acquired melanocytic nevi characterized by junctional and/or dermal nests of large cells with a clear and foamy cytoplasm which has rarely been described in children. Three cases of BCN firstly reported on the scalp in two pediatric patients are presented along with a literature review. Dermoscopy is particularly indicated in those pigmented lesions showing a yellowish hue, in ruling out in real time those disorders that may clinically be similar such as xanthogranuloma and sebaceous nevus, and to suggest the diagnosis of BCN. The final diagnosis, however, is established by histopathological examination.

BAP1 tumor predisposition syndrome case report: pathological and clinical aspects of BAP1-inactivated melanocytic tumors (BIMTs), including dermoscopy and confocal microscopy

BACKGROUND

BRCA1 associated-protein 1 (BAP1) tumor predisposition syndrome is associated with an increased risk for malignant mesotheliomas, uveal and cutaneous melanomas, renal cell carcinomas, and singular cutaneous lesions. The latter are referred to as BAP1-inactivated melanocytic tumors (BIMTs). When multiple BIMTs manifest, they are considered potential markers of germline BAP1 mutations.

CASE PRESENTATION

Here, we report a novel pathogenic BAP1 germline variant in a family with a history of BIMTs, cutaneous melanomas, and mesotheliomas. We also describe singular pathological aspects of the patient's BIMT lesions and their correlation with dermoscopic and reflectance confocal microscopy findings.

CONCLUSIONS

This knowledge is crucial for the recognition of BIMTs by dermatologists and pathologists, allowing the determination of appropriate management for high-risk patients, such as genetic investigations and screening for potentially aggressive tumors.

Uncommon Histopathological Variants of Malignant Melanoma: Part 1

Despite new horizons opened by recent advances in molecular pathology, histological evaluation still remains the diagnostic gold standard regarding cutaneous melanocytic neoplasms. Several histological variants of melanoma have been described, and their knowledge is crucial for accurate diagnosis and classification of cases with unusual clinicopathological features. Uncommon histological variants of melanoma have been described based on a broad constellation of features, including architectural pattern, stromal alterations, cytological attributes, and other morphological properties. This review is aimed at providing an extensive discussion of unusual but distinctive histopathological variants of melanoma.

Unusual Histopathological Patterns in Melanocytic Nevi With Some Previously Undescribed Patterns

Melanocytic nevi are one of the most common diagnoses in the daily practice of any dermatopathologist. Although in the vast majority of cases the final diagnosis is not difficult, there are certain rare and unusual morphologic variations that can elicit some diagnostic problems. Although some of these variations can be considered as mere morphologic oddities, others might lead to a differential diagnosis with melanoma, or with other tumors, including epithelial or neural tumors. In the current report, we review many of these morphologic variations and discuss the main differential diagnosis, when appropriate.

Clear cell proliferations of the skin

Clear cell proliferations of the skin consist of a diverse group of lesions characterized by the presence of cells with abundant clear cytoplasm. They may arise from primary, metastatic, or non-neoplastic origins, with their distinctive cytoplasmic clearing attributable to causes ranging from artifact to accumulation of materials such as glycogen, mucin, or lipids. Despite the heterogeneity of these lesions, their distinguishing characteristics may be subtle, especially at high power. As such, histologic diagnosis can be challenging, and proper consideration relies on an understanding of the scope of possible origins, etiologies, and key immunohistochemical staining patterns of the various entities. This review categorizes cutaneous clear cell neoplasms by histogenesis, and offers differential diagnostic strategies to aid in their clinicopathologic evaluation.

Clear Cell Melanoma: A Cutaneous Clear Cell Malignancy

Clear cell melanoma is a rare clear cell malignancy. Accurate diagnosis of clear cell melanoma requires integration of immunohistochemical and morphologic findings, with molecular studies to rule out clear cell sarcoma. The differential diagnosis includes melanoma, carcinoma, perivascular epithelioid cell tumor, and epidermotropic clear cell sarcoma. We use a case of a lesion on the helix of an 86-year-old man as an example. Histologic examination revealed an ulcerated clear cell malignant tumor. Tumor cell cytoplasm contained periodic acid-Schiff–positive, diastase-sensitive glycogen. Tumor cells showed positive labeling for S100, HMB-45, and Melan-A, and negative labeling for cytokeratins, p63, and smooth muscle actin. Molecular studies demonstrated BRAF V600E mutation, copy gains at the 6p25 (RREB1) and 11q13 (CCND1) loci, and absence of EWSR1-ATF1 fusion. These findings supported a diagnosis of clear cell melanoma. The rare pure clear cell morphology occurs due to accumulation of intracytoplasmic glycogen. We review the differential diagnosis of clear cell melanoma and describe the utility of immunohistochemical and molecular studies in confirming this diagnosis.