Pigmented primary cutaneous balloon cell melanoma demonstrating balloon cells in the dermoepidermal junction: a brief case report with dermatoscopy and histopathology

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.

Balloon cell melanoma: a systematic review

Balloon cell melanoma (BCM) is a rare presentation of malignant melanoma characterized by large, foamy melanocytes lacking pigmentation. This is a comprehensive review of the clinical, dermoscopic, and histological features among BCM cases reported in the literature. A systematic review of all case reports and series published since 1970 was conducted via MEDLINE, Embase, and Web of Science, using "balloon cell melanoma" and synonymous search terms. Our systematic search identified 76 cases (49% male, 51% female) of BCM in the literature. The mean age at presentation was 57.81 years. Prior skin cancer, particularly melanoma (47%), accounted for 58% of pertinent medical history. Prominent clinical exam findings included raised (46%), ulcerated (73%) lesions larger than 1 cm (68%) in the lower extremities (35%). Median Breslow thickness of primary BCM cases was 2.5 mm. Hairpin vessels (75%) and structureless architecture (75%) were predominant on dermoscopy. Notable histopathology included large (47%), vacuolated (58%) cells with foamy cytoplasm (62%) and conspicuous nucleoli (27%). Positive S-100 immunohistochemistry (73%) was most frequently employed to diagnose BCM. We observed 47% primary and 53% metastatic BCM cases. Of metastatic BCMs, balloon cells in the primary lesion were unknown in 48%, devoid in 33%, and present in 20% of cases. All metastases displayed predominant balloon cell morphology. BCM may represent an advanced phase in the progression of malignant melanoma. Improved awareness of BCM characteristics among clinicians may reduce the risk of misdiagnoses.

Clinical and Dermoscopic Features Associated With Difficult-to-Recognize Variants of Cutaneous Melanoma: A Systematic Review

Importance

The clinical and dermoscopic features of the vast majority of uncommon variants of cutaneous melanoma have been rarely reported, leading to difficulty in making accurate diagnoses.

Objective

To define the main clinical and dermoscopic features of the most frequently reported but uncommon histologic variants of cutaneous melanoma.

Evidence Review

A 2-step systematic review of the literature was performed (from inception to November 2018) using PubMed, Embase, and Cochrane Central Register of Controlled Trials databases. The first step identified those uncommon variants of melanoma for which at least 1 case reporting dermoscopy was described in the literature. The keywords searched were melanoma, uncommon, rare, dermoscopy, and dermatoscopy. In the second step, each previously identified uncommon variant was searched for in the same databases by combining the following terms with melanoma, dermoscopy, and dermatoscopy: amelanotic, hypopigmented, animal, melanocytoma, balloon, desmoplastic, follicular, nested, nevoid, dermal, spitz*, spindle, and verrucous. The institution's database was also searched from January 2012 to September 2019 for histopathologically confirmed cases of the same melanoma variants. Each reviewer also assessed the quality of reporting in the included articles based on previously described guidelines.

Findings

In total, 62 articles met the inclusion criteria, reporting 433 melanoma cases. An additional 56 cases of uncommon melanoma variants were retrieved from the institution's database for a total of 489 cases: 283 cases of amelanotic superficial spreading melanoma, 18 cases of animal-type and pigmented epithelioid melanocytoma, 7 cases of balloon cell melanoma, 71 cases of desmoplastic melanoma, 3 cases of follicular melanoma, 10 cases of nested melanoma, 33 cases of nevoid melanoma, 2 cases of primary dermal melanoma, 57 cases of spitzoid melanoma, and 5 cases of verrucous melanoma. These variants of melanoma occurred more frequently in women than men (147 cases vs 132 cases). Clinically, these tumors were mainly palpable (162 of 217 [74.7%]) or amelanotic (283 of 489 [57.9%]) lesions that could resemble other benign or malignant skin conditions; dermoscopy typically revealed a homogeneous pinkish background, white structures, and polymorphic vessels. The mean age of all included was 58 years (range, 1-89 years).

Conclusions and Relevance

Uncommon melanoma variants may resemble both inflammatory disorders and other cutaneous neoplasms, representing a diagnostic pitfall even for the most experienced dermatologist. The purpose of this systematic review was to provide an extensive and detailed overview of specific clinical and dermoscopic features of each uncommon melanoma variant, highlighting the main criteria for differentiating these variants from other benign or malignant skin lesions.

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.

Association of Clinical, Dermoscopic, and Histopathologic Findings With Gene Expression in Patients With Balloon Cell Melanoma

Importance

Balloon cell melanoma is a rare subtype of melanoma that is underrecognized clinically and is challenging to diagnose on histologic studies.

Objective

To further characterize the clinical, dermoscopic, and histopathologic features of balloon cell melanomas and their correlation to gene expression.

Design, Setting, and Participants

Case series of 2 patients with balloon cell melanoma whose medical records were retrieved from the database of Thomas Jefferson University Dermatopathology Center in Philadelphia, Pennsylvania. Both cases had been referred to the institution's dermatopathology laboratory and provided complete data on clinical, dermoscopic, and histopathologic findings and gene-expression profiles.

Main Outcomes and Measures

Dermoscopic findings, histopathologic findings, and results of gene expression tests.

Results

In the 2 patients included, translucent hypopigmented areas on gross examination and a translucent white-gray veil and dull yellow globules on dermoscopic examination correlated with the balloon cell melanocytic region demonstrated on histologic studies with hematoxylin-eosin stain. Specifically, dull yellow globules corresponded to the balloon cell melanocytic nests. Both lesions presented with a second, morphologically distinct population of melanocytes, common in balloon cell melanocytic neoplasms. In both cases, a prominent junctional component that consisted of cells demonstrating ample clear-to-granular cytoplasm and a central nucleus were present. Cytologic atypia was minimal to lacking in both cases, and architectural disorder served as a better clue to the diagnosis. Findings of a gene expression profiling test corroborated the diagnosis in both cases.

Conclusions and Relevance

Balloon cell melanomas may present with characteristic clinical and dermoscopic findings, and a gene expression profiling test may provide additional useful diagnostic information in cases that are difficult to interpret.