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Case Reports
. 2024 Apr 18;16(4):e58523.
doi: 10.7759/cureus.58523. eCollection 2024 Apr.

The Utility of Radiologic Imaging and Full Body Skin Examination in Patients With Melanoma of Unknown Primary

Parisa ShamaeiZadeh  1 , Elliott Campbell  2 , Nneka Comfere  3   2
Affiliations
Case Reports

The Utility of Radiologic Imaging and Full Body Skin Examination in Patients With Melanoma of Unknown Primary

Parisa ShamaeiZadeh et al. Cureus. .

Abstract

Although most melanomas have a cutaneous origin, melanomas are rarely discovered without an overt primary site and are found in the metastatic stage. This phenomenon is called melanoma of unknown primary (MUP), which was first recorded in 1963.Melanoma can also rarely present as tumoral melanosis, which has completely regressed. By definition, this does not have viable melanocytes and histologically presents as an infiltration of melanophages and melanin. A 71-year-old female presented for dermatologic evaluation after being found to have melanoma of unknown primary (MUP). The MUP, located in multiple lymph nodes of the left superior and inferior inguinal region, was found on preoperative imaging indicated for surgical management of endometrial carcinoma. After the biopsy, a positron emission tomography-computed tomography (PET-CT) scan was performed to determine the extent of involvement, which noted focal uptake of the left heel of just medial to midline with an SUV max of 2.1. Based on the PET-CT findings, the patient was questioned about the lesion on her heel. She had suspected this was due to friction and stated it had been asymptomatic and present for years. This unique case demonstrates that combined total skin examination and whole-body radiologic imaging (preferably PET-CT) are both critical elements in the evaluation of MUP. Since melanoma of unknown primary is at least American Joint Committee on Cancer (AJCC) 8 Stage III (due to N1 status), imaging is reasonable in these patients.

Keywords: dermatology; melanoma; melanoma of unknown primary; pet-ct; tumoral melanosis.

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Conflict of interest statement

Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. PET-CT scan results noting focal uptake of the left heel just medial to midline
PET-CT: positron emission tomography-computed tomography
Figure 2
Figure 2. The left plantar heel with dermoscopic imaging
A slightly deep, darkened hue can be appreciated under the keratin.
Figure 3
Figure 3. The left plantar heel
Hyperkeratotic plaque with a subtle deep blue hue underlying the keratin.
Figure 4
Figure 4. Panel A: Skin biopsy demonstrating a nodular dermal-based mass with pigmentation on H&E, 1.25x magnification; Panel B: Demonstration of melanophages without viable melanocytes on H&E, 20x magnification; Panel C: Fontana Masson demonstrating pigmentation on 20x magnification; Panel D: Melan A highlights a lack of viable melanocytes on 20x magnification
See this image and copyright information in PMC

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