Case Report and Literature Review of Giant Cutaneous Malignant Melanoma: What’s Keeping Patients Away?

Giant cutaneous malignant melanoma (MM) is a rare manifestation of melanoma and a term that has previously been used to define lesions that are at least 10 cm in diameter¹ or 48 mm in thickness.² Due to the large size of these lesions, there is a necessary delay in presentation by patients, although there is no substantial body of evidence considering why this might be the case. Furthermore, because of the rarity of these lesions, there is a lack of strong evidence as to whether they may require any specific management in comparison to thinner metastatic melanomas. This case report presents a unique case of giant cutaneous MM, reviews the existing medical literature around this rare condition, and discusses potential factors influencing late presentation.

The patient in this case report was referred to the plastic surgery department and was followed up for a year after the initial operation. The literature review was performed by searching the PubMed database using the term “giant malignant melanoma”. Results were searched for further articles, and any other incidental articles discovered were also included in the analysis.

A 55-year-old male building surveyor with no significant past medical history was referred to the department of plastic surgery with a large mass on his right shoulder. He reported that this lesion had been present and increasing in size for more than 6 months, but he neglected to present to his general practitioner until he was unable to satisfactorily dress the wound in the community. The lesion measured 20 cm x 18 cm in size, was heterogeneous in colour, and was situated on the superior aspect of the shoulder to which it was attached by a stalk of tissue (Figure 1a and 1b). It was also discharging blood-stained fluid.

The lesion was initially treated as a squamous cell carcinoma, and an incision biopsy was taken. However, because of postoperative bleeding, a wide excision with 1-cm peripheral margins down to muscle was performed the following the day with direct wound closure. Maggots were identified macroscopically within the lesion.

Subsequent histology confirmed the lesion to be a T4b MM. Breslow thickness was measured as at least 50 mm, demonstrating ulceration and lymphovascular invasion, and the tissue was positive for BRAF. The surgical margins were clear with 32 mm peripherally and over 1 cm at the deep margin.

His subsequent management was guided by a multidisciplinary team. The patient underwent further staging investigations, with a computed tomography head and subsequent magnetic resonance imagine finding a 2.6-cm mass in the left frontal lobe consistent with a metastatic lesion. This was accompanied with cervical and axillary metastases alongside a suspicious pulmonary nodule. The cerebral metastasis was resected with an image-guided awake craniotomy and stereotactic radiosurgery. He presented with new lesions over the right shoulder near the original site of excision 2 months post diagnosis. These were excised, and subsequent histology demonstrated 2 satellite/in-transit metastases. He then underwent immunotherapy with nivolumab and ipilimumab, initially with 3 cycles and the potential for further treatment.

One year after his initial operation, the patient is alive, well, and showing excellent response to treatment.

MM is the fifth most common cancer in England.³ Giant MMs are rare but potentially devastating manifestations of melanoma, and little is known about whether they require specific management in comparison to smaller melanomas. Furthermore, there is no evidence in the literature as to why patients may delay presentation long enough for giant MM to develop.

A literature review was performed on the presentation, management, and reasons for delay in presentation in all cases of giant MM reported to date. These results are summarised in the Table.^1,2,4–14 The patient in this report had one of the largest cases of giant cutaneous MM to date. He initially self-managed his lesion in the community through dressing care and only presented to primary care after no longer being able to dress and clean it himself. He reports that in hindsight he thought it might have been cancer but was ignoring it and hoped that it would resolve by itself. He also stated concerns about being judged negatively for having neglected it. Reasons for delayed presentation were not systematically reported in the literature but include self-neglect and failure to continue managing the wound in the community, as well as misconceptions about the aetiology of the tumour and associated psychiatric disorders. The most common stimulus for presentation to primary/secondary care was bleeding and increase in size.

Furthermore, this is the first reported case of giant MM demonstrating an excellent response to adjuvant immunotherapy after successful wide excision. This suggests that they can be successfully managed as per more common, thinner metastatic MMs. Previous reports have shown these to be treated with wide local excision/reconstruction, with or without lymph node dissection, radiotherapy, chemoradiotherapy, and the use of drugs against specific chemical targets, including BRAF. Regarding systemic therapies, only few patients to date have been treated with these. Imamura et al¹³ reported a case where the patient received a BRAF inhibitor in the form of Vemurafenib, and this showed partial response. di Meo et al⁹ reported a case where the patient received chemotherapy in the form of dacarbazine with good response. In the article by Grisham et al,⁸ the patient had some immunotherapy in the form of alpha-interferon and enrolment in the ECOG 4697 protocol; however, no response was documented.

This case report presents one of the largest cases of giant cutaneous MM to date and the first in the literature to show an excellent response to adjuvant immunotherapy. In order to reduce the burden of disease from giant MM, there remains a significant need for education on the importance of seeking medical attention, especially among vulnerable patients, and ensuring that when patients do present, they can do so without feeling embarrassed or judged.

Affiliations:¹Department of Plastic Surgery, Salisbury District Hospital, Salisbury, UK

Correspondence: Jamie A Mawhinney BA, BMBCh, MRCS(Eng); jamie.mawhinney@nhs.net

Presented in abstract form at BASO Annual Scientific Virtual Meeting 20th-22nd November 4th, 2021.

Ethics: Signed informed consent was obtained from the patient for publication of this case report and all accompanying clinical information and images.

Disclosures: The authors declare no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.