10.5826/dpc.1304a213
text/xml
2160-9381
2967
en
Simonetta Piana
https://creativecommons.org/licenses/by-nc/4.0
Dermatology Practical & Conceptual
Merkel Cell Carcinoma: Mind The Genital Metastatic Sites!
Text.Serial.Journal
https://dpcj.org/index.php/dpc
Letter to the Editor
2023-10-31
2022-11-15
2023-10-31
2024-01-15
e2023213
Dermatol Pract Concept
Simonetta Piana
2023/10/31
10.5826/dpc.1304a213
e2023213
Pathology Unit, Arcispedale Santa Maria Nuova, Azienda USL Reggio Emilia-IRCCS, Reggio Emilia, Italy
2160-9381
en
e2023213
Laffi A, Cozzi G, Spada F, et al. Metachronous testicular metastases from Merkel cell Carcinoma (MCC): a case report and literature review. Am J Case Rep. 2022; 23:e936552. doi: 10.12659/AJCR.936552. PMID: 36031755
Merkel Cell Carcinoma: Mind The Genital Metastatic Sites!
https://dpcj.org/index.php/dpc/article/download/2967/2359
               Merkel Cell Carcinoma: Mind the Genital
                           Metastatic Sites!
            Giacomo Santandrea1,4, Stefania Borsari2, Angelina Filice3, Simonetta Piana1


1 Pathology Unit, Arcispedale Santa Maria Nuova, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
2 Centro Oncologico ad Alta Tecnologia Diagnostica-Skin Cancer Center, Azienda USL– IRCCS di Reggio Emilia, Reggio Emilia, Italy
3 Nuclear Medicine Unit, Arcispedale Santa Maria Nuova, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
4 Clinical and Experimental Medicine PhD Program, University of Modena and Reggio Emilia, Modena, Italy



Citation: Santandrea G, Borsari S, Filice A, Piana S. Merkel Cell Carcinoma: Mind The Genital Metastatic Sites! Dermatol Pract Concept.
2023;13(4):e2023213. DOI: https://doi.org/10.5826/dpc.1304a213
Accepted: April 26, 2023; Published: October 2023
Copyright: ©2023 Santandrea et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-
NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use,
distribution, and reproduction in any medium, provided the original authors and source are credited.
Funding: None.
Competing Interests: None.
Authorship: All authors have contributed significantly to this publication.
Corresponding Author: Dr. Simonetta Piana, Pathology Unit, Azienda USL-IRCCS Reggio Emilia, Viale Risorgimento 80, Reggio Emilia,
Italy. TEL +39 0522 295919 FAX +39 0522 296945 E-mail: Simonetta.Piana@ausl.re.it




To the Editor,                                                           However, rare metastatic sites may occur, and they can be
                                                                         overlooked; genitourinary tract and specifically testes can
Merkel cell carcinoma (MCC) is a rare neuroendocrine                     represent a neglected metastatic localization.
tumor of the skin, presenting mostly in sun-exposed site                      A man, aged 50 years, was diagnosed with a skin MCC
of Caucasian elderly patients. The median age is 75 years,               of left knee. The lesion was located in the deep dermis and
with less than 5% of patients younger than 50 years. MCC                 measured 1 cm in the greatest axis. As expected, MCC re-
is associated with immunosuppression and its incidence is                sulted immunohistochemically positive with chromogranin
increasing worldwide. Merkel cell polyomavirus (MCPyV),                  and keratin 20, but it was also immunoreactive with MCPyV
demonstrated either immunohistochemically or by PCR in                   antibody. He underwent a tumor excision, followed by a
a subset of MCC, and the UV damage are probably inter-                   negative sentinel lymph node procedure and a Computed
related etiopathogenetic agents. Even if, in the past, it was            Tomography (CT) scan, which ruled out any metastases.
considered almost indolent, now it is classified as a high-              Nine months later, on the Positron Emission Tomography–
grade malignancy, especially because it often disseminates               Computed Tomography scan with 2-deoxy-2-[ 18F]
distantly. After lymph nodes, the most common sites of dis-              fluoro-D-glucose (2-[ 18F]FDG PET/CT), performed for rou-
tant metastases are skin/soft tissue (25%), liver (23%), bone            tine follow-up, a 4-centimeter solid mass with a high uptake
(21%), pancreas (8%), lung (7%) and brain (5%) [1]. As a                 (­SUVmax 10), was found in the right testis (Figure 1). A right
result, during staging procedures, the aforementioned body               radical orchiectomy was performed, with the suspicion
sites must be evaluated carefully as regional lymph nodes.               of a germ cell tumor. At histology, the mass was composed




Letter to the Editor | Dermatol Pract Concept. 2023;13(4):e2023213                                                                        1
Figure 1. (A) [18F]F-FDG PET/CT transaxial images with low-dose CT. (B) PET. (C) Image fused PET/CT. (D) Maximum intensity projection
(MIP). The red arrows in images B, C and D, shows a focal uptake (SUVmax 10) in the right testis.




of neoplastic epithelial cells with fine granular chromatin         single testis metastasis does not necessarily mean a systemic
and nuclear molding (Figure 2A), immunohistochemically              disease as the patients without other extra-testicular local-
positive with keratin 20 (Figure 2B) and chromogranin. Anti         ization experimented a survival longer than 1 year [6].
MCPyV antibody was positive as well (Figure 2C). Overall,               In MCC, the main prognostic factors are regional and
morphological findings were suggestive of a metastasis from         distant metastases. If localized, MCC carries the best prog-
a MCC. A subsequent total body CT scan excluded any fur-            nosis (50.6% 5-year overall survival [OS] rate ). In regional
ther localization.                                                  and distant disease, 5-year OS was estimated to be 35.4%
    Testis is a very rare metastatic site from MCC [2-6]. In a      and 13.5%, respectively [1]. The surveillance strategies
recent review [6], only eleven cases of testicular MCC metas-       during follow up are therefore crucial. As examination of
tases are reported in literature. At variance with the present      the genitals is not usually included in routine follow-up of
cases, most patients presented with already advanced or lo-         MCC, dermatologists should at least advice patients on
cally advanced stage at diagnosis. According to the authors,        self-examination.




2                                                                    Letter to the Editor | Dermatol Pract Concept. 2023;13(4):e2023213
                  Figure 2. (A) MCC growing through the seminiferous tubules of the testicular parenchyma. (B) MCC
                  immunohistochemical positivity with cytokeratin 20. (C) MCPyV is detected in neoplastic cells.




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Letter to the Editor | Dermatol Pract Concept. 2023;13(4):e2023213                                                                    3
