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Abstract: Merkel cell carcinoma (MCC) is an uncommon highly aggressive cutaneous neuroendocrine neoplasm with high mortality. Rarer still is nasopharyngeal metastasis of MCC. Herein, we report the 68Ga-DOTATATE PET/CT findings of MCC with metastasis to the nasopharynx in a 53-year-old man who underwent surgery for MCC in his thigh 2 years ago., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Localization of non-palpable melanoma, Merkel cell carcinoma (MCC) and soft tissue sarcoma (STS) lesions can be difficult due to size, location, and obesity of patients or fibrosis due to previous treatments. Magnetic seed localization (MSL) is a common method to localize non-palpable breast lesions, but the feasibility of MSL for non-palpable melanoma, MCC and STS lesions has not yet been described., Methods: In this retrospective single center cohort study, all consecutive patients between January 2021 and October 2023 who had a resection of a non-palpable melanoma, MCC or STS lesion guided by Sirius Pintuition, a MSL technique, were included. The primary endpoint was successful lesion localization during surgery and the secondary endpoints were seed migration, negative resection margins, and complications., Results: Seventy-nine seeds were placed for 76 lesions, which were resected during 68 surgeries in 61 patients. All lesions (100 %) were localized and resected. Median time of surgery was 44 min. No seed migration was observed. A negative resection margin was achieved for 60 (78.9 %) lesions. Clavien Dindo grade ≥2 complications occurred in 7.4 %., Conclusion: Magnetic seed localization with Sirius Pintuition is feasible for both non-palpable melanoma, MCC, and STS lesions., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: WJ Van Houdt reports financial support was provided by Sirius Medical Systems B.V. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background: Merkel cell carcinoma (MCC) is a rare, aggressive, cutaneous tumour with high mortality and frequently delayed diagnosis. Clinically, it often manifests as a rapidly growing erythematous to purple nodule usually located on the lower extremities or face and scalp of elderly patients. There is limited available data on the dermoscopic findings of MCC, and there are no specific features that can be used to definitively diagnose MCC., Aim of the Study: Here, we aimed to summarize existing published literature on dermatoscopic and reflectance confocal microscopy (RCM) features of MCC., Materials and Methods: To find relevant studies, we searched the PubMed and Scopus databases from inception to April 12, 2023. Our goal was to identify all pertinent research that had been written in English. The following search strategy was employed: (" dermoscopy" OR " dermatoscopy" OR " videodermoscopy" OR " videodermatoscopy" OR " reflectance confocal microscopy") AND " Merkel cell carcinoma". Two dermatologists, DK and GE, evaluated the titles and abstracts separately for eligibility. For inclusion, only works written in English were taken into account., Results: In total 16 articles were retrieved (68 cases). The main dermoscopic findings of MCC are a polymorphous vascular pattern including linear irregular, arborizing, glomerular, and dotted vessels on a milky red background, with shiny or non-shiny white areas. Pigmentation was lacking in all cases. The RCM images showed a thin and disarranged epidermis, and small hypo-reflective cells that resembled lymphocytes arranged in solid aggregates outlined by fibrous tissue in the dermis. Additionally, there were larger polymorphic hyper-reflective cells that likely represented highly proliferative cells., Conclusion: Dermoscopic findings of MCC may play a valuable role in evaluating MCC, aiding in the early detection and differentiation from other skin lesions. Further prospective case-control studies are needed to validate these results., (© 2024. The Author(s).)

A 67-year-old female presented with 2 weeks of right eye pain, redness, and diplopia. An orbital mass was found on magnetic resonance imaging (MRI), and biopsy revealed Merkel cell carcinoma (MCC). She had no primary head or neck lesion and no previous history of MCC. Positron emission tomography (PET) scan showed hypermetabolic subcutaneous lesions of the lower extremity andmultiple osseous lesions of the axial and appendicular skeleton. She received palliative external radiation of 20 Gy in 5 fractions to the orbit. After discussing immunotherapy, she opted for comfort care and expired 1 month later. To the best of our knowledge, this is only the third case of MCC with distant metastasis to the orbit and the first case in which the patient had no previous diagnosis of MCC and no known primary tumor.

Abstract: Cutaneous Merkel cell carcinoma with local nodal metastasis is a rare entity. A 56-year-old man presented with a nontender left inguinal mass, and ultrasound-guided biopsy of this nodal mass confirmed nodal metastasis with strong neuroendocrine differentiation from cutaneous Merkel cell carcinoma. Staging 18 F-FDG PET/CT showed a solitary 3.9 × 6.8-cm hypermetabolic left groin mass with no other suspicious lesions elsewhere. To confirm the patient's eligibility for radical curative treatment, taking into consideration of its neuroendocrine differentiation, a subsequent 18 F-AIF-NOTA-octreotide PET/CT was performed, which demonstrated only solitary somatostatin receptor-positive left inguinal mass. The patient underwent radical treatment., Competing Interests: Conflicts of interest and sources of funding: none declared. This article was supported by Key Research and Development Program of Shanxi Province (201903D321187)., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Immune checkpoint inhibitor treatment of patients with metastatic Merkel cell carcinoma (mMCC) has shown high response rates, ranging from 33% to 73%. The ideal duration of treatment, however, is currently unknown. The aim of this study was to evaluate if avelumab treatment for mMCC can be safely stopped after 1 year of treatment and a complete response (CR) confirmed by fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) imaging., Methods: Patients who received more than one dose of avelumab treatment for mMCC between November 2017 and February 2022 were included in this study. Treatment was discontinued in case of a FDG-PET/CT confirmed CR after 1 year (26 cycles) of avelumab or a CR and unacceptable toxicity earlier. The primary end point was recurrence-free survival (RFS)., Results: Sixty-five patients were included: 25 (38%) had a FDG-PET/CT-confirmed CR at discontinuation of avelumab. In those 25 patients, reasons for discontinuation of treatment were completion of 1 year of treatment in 13 (52%), toxicity in five (20%), and patient preference in seven (28%). Median duration of treatment in this group was 11 months (interquartile range, 6.1-11.7). Median follow-up was 27 months (interquartile range, 15.8-33.8). The 12-month RFS was 88% (95% CI, 0.74-1) and median RFS was not reached. Two patients (8%) had a recurrence at 4 and 7 months after discontinuation of treatment., Conclusions: Patients with mMCC who acquire a CR on PET/CT imaging appear to have durable responses after discontinuation of treatment after 1 year., (© 2023 American Cancer Society.)

Merkel cell carcinoma (MCC) is a rare and very aggressive skin cancer. An 83-year-old female presented with a 1.5 cm-sized non-tender mass on her left cheek and was diagnosed with MCC. The margin of MCC was well-defined and there was no cervical node metastasis on pre-operative computed tomography. Three weeks after the first visit, the mass rapidly increased in size. We checked the magnetic resonance imaging, a rapid-growing 2.5 cm sized nodular region and metastatic cervical lymph node were found. We performed wide excision of the MCC and neck lymph need dissection with multidisciplinary cooperation. The soft tissue defect was about 6.0×5.0 cm 2 in size and reconstructed with radial forearm free flap. On permanent biopsy, the size of MCC was 3.0×2.3 cm 2 . There was no recurrence of MCC with radiation therapy during an 18-month follow-up. We experienced an older patient with a rapid - growing MCC and cervical lymph node metastasis in a brief time. With our experience, we discuss the evaluation and treatment plan of the rapid-growing MCC for good results., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

Background: Merkel cell carcinoma (MCC) is a cutaneous tumor with a high tendency to metastasize, and a significant proportion of patients have metastases at first presentation. This study aims to determine the value of baseline ultrasound (US) and  18 fluorodeoxyglucose-positron emission tomography/computed tomography ( 18 FDG-PET/CT) imaging in both patients with clinically localized MCC (Stage I/II) and patients who present with palpable lymph nodes (Stage III)., Methods: This retrospective cohort included 135 MCC patients who underwent baseline US (with fine needle aspiration cytology (FNAC)) and/or FDG-PET/CT imaging between 2015 and 2021., Results: Of the 104 patients with clinically localized disease, 48% were upstaged to Stage III and 3% to Stage IV by imaging or sentinel lymph node biopsy (SLNB). FDG-PET/CT imaging identified regional metastases in 23%, while US with FNAC identified regional metastases in 19%. SLNB was performed in 56 patients, of whom 57% were upstaged to Stage III. Of the 31 patients who presented with palpable lymph nodes, 16% were upstaged to Stage IV by FDG-PET/CT imaging., Conclusion: Baseline imaging frequently upstages Stage I/II MCC patients to Stage III, both by US and FDG-PET/CT, Stage IV disease is rarely identified. Patients who present with palpable nodes are frequently upstaged to Stage IV by FDG-PET/CT imaging., (© 2022 The Authors. Journal of Surgical Oncology published by Wiley Periodicals LLC.)

Objective: The purpose of the current study was to evaluate the diagnostic accuracies of 18 F-FDG PET or PET/CT for diagnosis of Merkel cell carcinoma (MCC) through a systematic review and meta-analysis., Methods: The PubMed, Cochrane database, and EMBASE database, from January 1990 to January 31, 2022, were searched for studies evaluating diagnostic performance of 18 F-FDG PET or PET/CT for MCC. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves., Results: Across 9 studies (259 patients), the pooled sensitivity of 18 F-FDG PET or PET/CT was 0.91 (95% confidence interval [CI], 0.85-0.95) and a pooled specificity of 0.93 (95% CI, 0.86-0.97). Likelihood ratio syntheses gave an overall LR+ of 14.0 (95% CI, 6.6-29.6) and LR- of 0.09 (95% CI, 0.05-0.17). The pooled diagnostic odds ratio was 153 (95% CI, 57-416)., Conclusion: 18 F-FDG PET/CT showed an excellent performance for diagnosis of MCC. The likelihood ratio scattergram indicated that 18 F-FDG PET or PET/CT is useful for exclusion and confirmation of MCC. Further large multicenter studies would be necessary to substantiate the diagnostic accuracy of 18 F-FDG PET or PET/CT for MCC patients., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

The purpose of this study was to investigate the diagnostic and prognostic value of 18 F-FDG PET/CT for surveillance imaging in patients treated for stage III Merkel cell carcinoma (MCC). Methods: This retrospective study included 61 consecutive stage III MCC patients who were clinically asymptomatic and underwent surveillance 18 F-FDG PET/CT. Findings were correlated with either pathology or clinical/imaging follow-up. The median follow-up period was 4.8 y. Statistical analyses were performed. Results: 18 F-FDG PET/CT detected unsuspected recurrences in 33% patients (20/61) with lesion-based sensitivity, specificity, and accuracy of 92%, 93%, and 93%, respectively. The mean ± SD SUV for malignant and benign lesions was 7.5 ± 3.9 and 3.8 ± 2.0, respectively. Unknown distant metastases, as first recurrence site, were noted in 12 of 61 patients. Those with positive disease on 18 F-FDG PET/CT within 1 y of definitive treatment had relatively worse overall survival ( P < 0.0001). After adjustment on stage, risk of death increased with a higher SUV max (hazard ratio for 1 unit = 1.17; P = 0.006) and with a higher number of positive lesions on 18 F-FDG PET/CT (hazard ratio for 1 additional lesion = 1.60; P < 0.001). Conclusion: Postdefinitive treatment surveillance 18 F-FDG PET/CT scanning detects unsuspected recurrences and has prognostic value. Inclusion of 18 F-FDG PET/CT within the first 6 mo after definitive treatment would be appropriate for surveillance and early detection of recurrence. Our data merit further studies to evaluate the prognostic implications., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: The purpose of this study was to report the prevalence and imaging features of abdominal metastases from Merkel cell carcinoma (MCC) on computed tomography (CT) examinations., Materials and Methods: A total of 111 patients with MCC from two institutions were initially identified. Of these, 27 patients (27/111; 24.3%) had abdominal metastases from MCC present on CT examination. There were 19 men and 8 women with a mean age of 75  ± 10.8 (SD) years (age range: 46-92 years). CT examinations were retrospectively reviewed by two radiologists and analyzed quantitatively for the number and dimensions of abdominal metastases from MCC and qualitatively in terms of location, margins, contours, homogeneity, patterns of enhancement, vascular involvement and extension of metastases from MCC., Results: Fifteen patients (15/27; 56%) had abdominal metastatic disease at initial diagnosis and twelve (12/27; 44%) developed abdominal metastases during the course of the disease. The mean number of locations of abdominal metastases was 2.1 ± 1.12 (SD) (range: 1-5). Abdominal metastases involved abdominal lymph nodes (16/27; 59%), adrenal glands/kidneys/retroperitoneum (14/27; 52%), mesentery/peritoneum (13/27; 48%), liver (7/27; 26%) and pancreas (7/27; 26%). Vascular involvement was found in association with peritoneal/mesenteric metastases in 6/13 (46%) patients with intraperitoneal metastases or in association with abdominal lymph nodes in 4/16 (25%) patients. Ureteral encasement and/or dilatation was found in 4/14 (28%) patients with retroperitoneal metastases and 3/16 (19%) patients with abdominal lymph nodes. Metastases to the liver, pancreas, peritoneum, retroperitoneum and adrenal glands displayed internal enhancement during the arterial phase in 1/2 (50%), 4/5 (80%), 4/7 (57%) and 5/8 (62%) patients for whom arterial phase was available, respectively., Conclusion: Metastases from MCC have a prevalence of 24.3% on CT examination and may involve a variety of abdominal organs, mainly lymph nodes, peritoneal and retroperitoneal structures, but also the liver and pancreas. CT features of abdominal metastases from MCC include hypervascularity during the arterial phase of enhancement and eventually vascular and ureteral involvement., Competing Interests: Disclosure of interests The authors declare that they have no competing interest., (Copyright © 2021 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Merkel cell carcinoma (MCC) of the breast is a very rare and aggressive type of neuroendocrine carcinoma of the breast (NECB) that typically occurs in older and immunocompromised individuals often presenting as a large palpable mass (Albright et al., 2018 1 ). Imaging features of MCC are similar to other NECBs, typically appearing as an oval circumscribed mass on mammography and as an irregular mass with increased vascularity on sonography (Jeon et al., 2014 2 ). While both MCC and primary NECB demonstrate positive immunostaining for synaptophysin, obtaining immunohistochemical stains for specific markers, such as CK7 and CK20 is imperative to confirm the diagnosis of MCC (Albright et al., 2018 1 ). We present a case of a 57-year-old female patient with no personal or family history of breast cancer, who presented for evaluation of a palpable abnormality in her left breast. Initial diagnostic mammogram demonstrated a circumscribed mass in the upper outer quadrant of the left breast corresponding to the palpable area of concern, which correlated to an irregular mass with increased vascularity on targeted ultrasound, similar to other NECBs. Pathologic results after tissue sampling yielded poorly differentiated primary NECB. Following neoadjuvant chemotherapy, the patient underwent a lumpectomy and further immunohistochemical stains of the lumpectomy specimen demonstrated diffusely positive synaptophysin, negative CK7, and positive CK20, consistent with MCC of the breast., (Copyright © 2021. Published by Elsevier Inc.)

Introduction: Merkel cell carcinoma (MCC) is a highly aggressive skin cancer with no survival benefit demonstrated using palliative cytotoxic chemotherapy in the setting of metastatic MCC. Recently, immune checkpoint inhibitors (anti-PD-L1/PD1) have been approved in this setting after durable clinical response was demonstrated in several clinical trials. In this series, we present a multicentre real-world experience in using anti-PD-L1/PD1 in advanced MCC., Methods: A retrospective review was performed of all patients with metastatic MCC who were treated with at least one dose of anti-PD-L1/PD1 presenting to Sydney West Cancer Network (Westmead, Nepean and Blacktown hospitals) was performed between 2016 and 2020. Treatment response was assessed based on morphologic and/or metabolic changes of the disease on FDG-PET/CT scans. Primary end point investigated was objective response rate. Secondary outcomes included therapy toxicity, disease control and overall survival., Results: Thirteen patients received anti-PD-L1/PD1 with a median age of 82 (range 62-89). Two patients had undergone prior palliative chemotherapy. The median follow-up time was 17 months (range 2-34). The overall, complete and partial response rates were 77% (10), 54% (7) and 23% (3), respectively. Treatment-related grade 1 or 2 toxicity was experienced by 69% with only 2 cases of greater severity. The median progression-free survival and overall survival were 18 months (95% CI 10-26 months) and 33 months (95% CI range 7.6-58.4 months), respectively., Conclusions: Consistent with clinical trial results, anti-PD-L1/PD1 therapy in this small series demonstrated efficacy and safety in patients with metastatic MCC., (© 2021 The Royal Australian and New Zealand College of Radiologists.)

Merkel cell carcinoma (MCC) is an aggressive skin cancer associated with a high risk of local recurrence and distant metastasis. Optimal care of this potentially life-threatening cancer is critical but challenging because: physicians are often unfamiliar with its management due to rarity, and MCC management remains controversial, in part because it is rapidly evolving across multiple specialties. While guidelines offer a broad overview of management, they are often not sufficient when making decisions for individual patients. Herein, we present a literature review as well as practical approaches adopted at our institutions for staging, surveillance and therapy of MCC. Each of these areas are discussed in light of how they can be appropriately customized for prevalent but challenging situations. We also provide representative examples of MCC patient scenarios and how they were managed by a multidisciplinary team to identify suitable evidence-based, individualized treatment plans.

OBJECTIVE. Whole-body imaging extending from the vertex of the head to the toes is considered the standard 18 F-FDG PET/CT protocol for Merkel cell carcinoma, though the evidence establishing this standard is scant. The purpose of this study was to investigate the clinical impact of PET/CT of the lower extremities in patients with Merkel cell carcinoma, a rare aggressive neuroendocrine tumor of the skin. MATERIALS AND METHODS. A total of 101 patients with Merkel cell carcinoma (mean age, 70.9 years) who underwent whole-body PET/CT were included. PET/CT findings in the lower extremities were evaluated on a per-patient basis, and the results were compared between patients with the primary lesion in the lower extremities (lower extremity primary) and those with the primary lesion located between the head and inguinal regions (body primary). Subsequent clinical evaluation and follow-up imaging were used as the reference standard. RESULTS. In the lower extremity ( n = 22) and body ( n = 79) primary groups, five and eight patients had true metastases in the lower extremities ( p = .15). In the body primary group, all metastases in the lower extremities were part of widespread metastases in the body. In contrast, three of five patients (60%) in the lower extremity primary group had isolated metastases in the lower extremities, which differed significantly from the rate in the body primary group ( p = .04). Subgroup analysis that included 48 patients who underwent initial staging examinations showed no metastases in the lower extremities regardless of primary location. CONCLUSION. PET/CT of the lower extremities for patients with body primary lesions of Merkel cell carcinoma should be considered of limited clinical utility.

Background: Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy with a propensity for regional and distant spread. Because of the relative infrequency of this disease, the patterns of metastasis in MCC are understudied., Methods: Patients with American Joint Committee on Cancer (8th edition) stage I-IV MCC treated at our institution were identified (1/1/2008-2/28/2018). The first site of metastasis was classified as regional [regional lymph node (LN) basin, in-transit] or distant. Distant metastasis-free (DMFS) and MCC-specific (MSS) survival were estimated., Results: Of 133 patients, 64 (48%) had stage I, 13 (10%) stage II, 48 (36%) stage III, and 8 (6%) stage IV disease at presentation. The median follow-up time in patients who remained alive was 36 (interquartile range 20-66) months. Regional or distant metastases developed in 78 (59%) patients. The first site was regional in 87%, including 73% with isolated LN involvement, and distant in 13%. Thirty-seven (28%) patients eventually developed distant disease, which most commonly involved the abdominal viscera (51%) and distant LNs (46%) first. The lung (0%) and brain (3%) were rarely the first distant sites. Stage III MCC at presentation was significantly associated with worse DMFS (hazard ratio 4.87, P = 0.001) and stage IV disease with worse MSS (hazard ratio 6.30, P = 0.002)., Conclusions: Regional LN metastasis is the most common first metastatic event in MCC, confirming the importance of nodal evaluation. Distant disease spread appears to have a predilection for certain sites. Understanding these patterns could help to guide surveillance strategies.

Only 2-3.9% of pancreatic malignancies represent metastases from other sites, the most common origins being the lungs, kidneys, and gastrointestinal tract. Differentiating between primary and secondary lesions may be challenging with imaging techniques but EUS-guided FNA is a safe, accurate procedure for obtaining a tissue diagnosis. We report the case of a 70-year-old male who, following satisfactory treatment for a Merkel-cell carcinoma in the right groin, presented with jaundice and an indurated, vascularized, adherent nodule on the right thigh. Endoscopic ultrasound identified a mass at the pancreatic head as well as a perilesional adenopathy with no evidence of vascular involvement. FNA revealed cell proliferation, which was immunohistochemically positive for CD56, synaptophysin, and chromogranin, these findings being consistent with poorly-differentiated neuroendocrine carcinoma. Given the patient's history we considered this lesion to be a pancreatic metastasis of Merkel-cell carcinoma, which represents a rare finding.

Introduction: The incidence of malignant melanoma has been rising steadily over the past decades and Merkel cell carcinoma is a highly aggressive neuroendocrine skin tumor with a high mortality rate. Sentinel lymph node (SLN) biopsy is a recommended prognostic tool in primary cutaneous malignant melanomas of intermediate thickness and in all clinically node-negative Merkel cell carcinomas. The gold standard method for identification of SLNs is lymphoscintigraphy, which involves radioactive tracers. Indocyanine green-based near-infrared fluorescence imaging (NIRFI) has been also used for intraoperative SLN identification. We aim to evaluate the diagnostic sensitivity of the VisionSense VS3 NIRFI device for SNL identification. This device uses stereoscopic 3D high definition for both fluorescence and visible light imaging. Our hypothesis is that SLNs may be identified transcutaneously using fluorescent dye injections and NIRFI; therefore, obviating the need for lymphoscintigraphy in the future. METHODS AND ANALYSIS:: lymph node identification in skin malignancy using indocyanine green transcutaneously is a prospective diagnostic sensitivity study conducted at the Department of Plastic and Hand Surgery at the University Hospital Berne, Inselspital, Switzerland. The study aims at recruiting 93 patients (start date September 2017) to compare the accuracy of VisionSense VS3 camera at identifying SLNs transcutaneously with the current gold standard, lymphoscintigraphy. Moreover, a secondary objective is to determine if anatomical location of the SLN and patient factors (eg, body mass index, age) have an impact on the ability of VisionSense to detect SLNs when compared with the same gold standard., Trial Registration Number: ClinicalTrials.gov NCT03545334.

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine tumor with a higher mortality rate than melanoma. Approximately 40% of MCC patients have nodal or distant metastasis at initial presentation, and one-third of patients will develop distant metastatic disease over their clinical course. Although MCC is rare, its incidence has been steadily increasing. Furthermore, the immunogenicity of MCC and its diagnostic and therapeutic application have made MCC one of the most rapidly developing topics in dermatology and oncology. Owing to the aggressive and complex nature of MCC, a multidisciplinary approach is necessary for management of this tumor, including dermatologists, surgeons, radiation oncologists, medical oncologists, pathologists, radiologists, and nuclear medicine physicians. Imaging plays a crucial role in diagnosis, planning for surgery or radiation therapy, and assessment of treatment response and surveillance. However, MCC is still not well recognized among radiologists and nuclear medicine physicians, likely owing to its rarity. The purpose of this review is to raise awareness of MCC among imaging experts by describing the epidemiology, pathophysiology, and clinical features of MCC and current clinical management with a focus on the role of imaging. The authors highlight imaging findings characteristic of MCC, as well as the clinical significance of CT, MRI, sentinel lymph node mapping, fluorine 18 fluorodeoxyglucose PET/CT, and other nuclear medicine studies such as bone scintigraphy and somatostatin receptor scintigraphy. © RSNA, 2019.

Purpose: To detect the expression of programmed death-ligand 1 (PD-L1) in Merkel cell carcinoma (MCC) and to determine the prognostic influence of the PD-L1 expression., Methods: A total of 13 patients with MCC were retrospectively evaluated (12 patients with primary skin lesion, one patient was diagnosed as unknown primary MCC). All patients underwent surgical resection. PD-L1 was determinated by imunohistochemistry. Immunostaining results were evaluated semiquantitatively. The prognostic influence of the expression of PD-L1 on overall survival (OS) was calculated with the Kaplan-Meier method and log-rank test., Results: PD-L1 positivity was detected in 8 patients (61.5%), in all cases the result was 1+. PD-L1 negativity was shown in the remaining 5 patients. In patients with PD-L1 positivity median OS was 42.1 months (95% CI 9.3-42.1) compared with median OS of 9.4 months (95% CI 2.1-80.9) in the group of patients without PD-L1 positivity (p=0.417)., Conclusions: PD-L1 positivity was found in 61.5% of patients with MCC. No prognostic significance of PD-L1 expression for OS was demonstrated.

A 77-year-old man with a history of metastatic Merkel cell carcinoma and debilitating painful cutaneous lesions was referred to our nuclear medicine department for peptide receptor radionuclide therapy with Lu-DOTATATE as ultimate therapeutic option. Post-treatment whole body scan showed multiple zones of Lu-DOTATATE uptake in the metastatic regions, which revealed significant improvement within the next 10 days of therapy. Peptide receptor radionuclide therapy in metastatic Merkel cell carcinoma is an effective therapeutic option that should be considered in earlier stages of the disease.

Merkel cell carcinoma (MCC) of the skin is a rare but aggressive cutaneous neuroendocrine-derived malignancy that predominantly affects elderly white males. The presence of distant nodal metastases significantly impacts survival. Typical metastatic sites of MCC are liver, bone, brain and skin. Gastrointestinal metastases are uncommon and small bowel is the most common site followed by stomach. We report a case of symptomatic MCC jejunal metastasis.

Merkel cell tumour is a rare skin tumour of high malignancy, poor prognosis and low survival. It is characterized by its tendency to lymph node and vascular invasion and by a high percentage of locoregional recurrence in the year following surgical removal. It affects adults between 60 and 80 years of age and often occurs in the head and neck. We present the case of an 85-year-old man presenting with an ulcerated gluteal mass of 4 months' evolution. Diagnosis was by histopathological and immunohistochemical study. Early diagnosis and appropriate treatment are important to improve the prognosis of these patients., (Copyright © 2019 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.)

Merkel cell carcinoma (MCC) is a rare malignant tumor with a neuroendocrine phenotype. The authors report a case of MCC of the left cheek region in an 85-year-old Caucasian woman who also received sentinel node biopsy using both Technectium-99m-labeled (99mTc) lymphoscintigraphy and indocyanine green lymphography.

Competing Interests: Competing interests: None declared.

The authors present the case of a woman in the seventh decade of life with medical history of: left nephrectomy for renal tuberculosis and non-Hodgkin's lymphoma treated with chemotherapy (QT) and radiotherapy. She presented with a 2-month history of non-tender, left inguinal lymph node enlargement. Positron Emission Tomography (PET) - CT -scanshowed hypermetabolic inguinal and retroperitoneal lymphadenopathies, no primary tumour. On the second dermatological examination a pink, 2 cm plaque on the anterior left knee was noted. The histopathological analysis revealed Merkel cell carcinoma. The patient underwent two lines of systemic QT, with life-threatening toxicities limiting treatment. Followed overwhelming disease progression with lymphoedema and numerous skin metastases in the left lower limb. The patient received palliative care until death. The rare incidence of such neoplasia and its uncommon clinical presentation justifies reporting this case and highlights the importance of multidisciplinary teams in the management of cancer patients., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background/objectives: Amelanotic nodular melanomas are notoriously difficult to diagnose and are responsible for a disproportionate burden of melanoma mortality. It is important to distinguish them from other amelanotic nodules. This study aimed to describe the dermoscopic features of a series of nodular melanomas and other amelanotic nodules and to determine whether dermoscopy improves diagnostic accuracy., Method: Retrospective analysis of 150 clinically amelanotic nodules with macroscopic and dermoscopic images., Results: In terms of classifying the nodules as malignant, dermoscopy was superior to unaided eye (specificity 89%; 95% CI 71-98% vs 67%; 95% CI 46-83%, P = 0.03). Dermoscopy enhanced sensitivity for the diagnosis of both amelanotic melanoma and SCC. In 19% of cases, using dermoscopy, the most likely diagnosis was changed from incorrect to correct. This included 26% of amelanotic melanomas which had a macroscopic misdiagnosis overturned to the correct diagnosis. Polymorphous vascular structures were more common in malignant nodules. 76% of amelanotic melanomas/Merkel cell carcinomas had polymorphous vessels compared with 38% of SCCs/KAs/BCCs and 22% of benign nodules (P < 0.001)., Conclusion: Dermoscopy improves diagnostic accuracy for amelanotic melanomas and other amelanotic nodules. Although dermoscopy improves diagnostic accuracy for amelanotic melanomas, these aggressive melanomas remain diagnostically difficult., (© 2018 The Australasian College of Dermatologists.)

Background: Ischiorectal fossa tumors are rare., Objective: This study reviews a single institution's series of ischiorectal tumors with comparison against presacral tumors and assesses the utility of preoperative biopsy and angioembolization., Design: This is a retrospective study., Settings: This study was conducted at a quaternary referral center., Patients: All patients with ischiorectal tumor treated between February 1995 and April 2017 were retrospectively reviewed. Tumors extending secondarily into the ischiorectal fossa and inflammatory pathologies were excluded., Interventions: Preoperative biopsy, neoadjuvant therapy, angioembolization, and surgical excision of these tumors were reviewed., Main Outcome Measures: Demographic, perioperative, pathological, and oncologic outcomes were evaluated., Results: Twenty-four patients (15 female; median age 54) were identified. Two-thirds were symptomatic. Forty-six percent had a palpable mass. All patients had CT and/or MRI. Fifty percent had a preoperative biopsy, of which 83% were diagnostic, and management was altered in 50%. All patients underwent surgical excision. Fifty-five percent had local excision, 38% had radical pelvic excision, and 8% had total mesorectal excision. Two patients had preoperative angioembolization. Both had successful R0 local excision. Morbidity occurred in 25%, with 1 major complication. There was no 30-day mortality. Histopathology demonstrated 17 soft tissue tumors (3 malignant), 2 GI stromal tumors, 1 neuroendocrine tumor, 1 Merkel cell carcinoma, 1 basaloid carcinoma, 1 epidermal cyst, and 1 lipoma. R0 resection was achieved in 75%. All patients were alive after a median follow-up of 33 months. Four patients developed recurrence at a median 10 months postoperatively. All recurrences were malignant, and 75% had had a R1 resection., Limitations: This study is limited by its small numbers. The quaternary institution source may introduce bias., Conclusions: Ischiorectal fossa tumors are heterogeneous and more likely to be malignant than presacral tumors. Biopsy can be useful if a malignant diagnosis is suspected and changes management in 50% of cases. Preoperative embolization may be useful for large vascular tumors. R0 resection is important to minimize recurrence. See Video Abstract at http://links.lww.com/DCR/A779.

Merkel cell carcinoma (MCC) is a rare malignant tumor of the skin. The development of MCC on non-sun-exposed skin is extremely rare, with few cases reported in the literature. The present authors aimed to highlight the characteristic features and treatment options of this tumor. The present authors present a 50-year-old man who developed MCC on the left gluteal region (non-sun-exposed skin). After surgery with clear margins, adjuvant radiotherapy was given. Three months after radiotherapy, lymphatic recurrence was observed and he was treated with chemotherapy. On follow-up, systemic metastases were found and palliative treatment was planned., (© 2018 Wiley Periodicals, Inc.)

Background: Merkel cell carcinoma (MCC) is a relatively rare skin cancer with high rates of regional lymph node involvement and metastatic spread. National Comprehensive Cancer Network guidelines recommend sentinel lymph node biopsy (SLNB) for staging purposes. The goal of this study is to report our experience utilizing indocyanine green (ICG) fluorescence-based technology to aid in SLNB detection in MCC., Methods: Consecutive MCC patients who underwent SLNB with radioisotope lymphoscintigraphy, with intraoperative handheld gamma probe, and ICG-based fluorescence imaging from 2012 to 2017 were prospectively studied (Cohort A). A group of historical controls that underwent SLNB for MCC with radioisotope lymphoscintigraphy and vital blue dye (VBD) (lymphazurin or methylene blue dye) was also analyzed (Cohort B)., Results: Twenty-four consecutive patients underwent SLNB with lymphoscintigraphy and ICG-based fluorescence and 11 controls underwent SLNB with lymphoscintigraphy and VBD. The localization rate by node with VBD was 63.6% and ICG-based fluorescence was 94.8%. For two patients, a positive sentinel lymph node (SLN) was detected only by ICG-based fluorescence and the nodes were not detected by gamma probe and one patient's only positive node was identified via ICG fluorescence only. VBD or gamma probe did not identify any unique positive SLNs in either cohort B or either cohort, respectively., Conclusions: In this study, we indicate that ICG-based fluorescence is not only feasible to augment SLN identification, but it has a higher node localization rate as compared to blue dye and it was able to identify positive SLNs otherwise missed by gamma probe. This study suggests the importance of utilizing two modalities to augment SLN identification and that ICG-based fluorescence may be able to identify nodes that would have been otherwise missed by gamma probe. We will continue to follow these patients and enroll more patients in this prospective study to further determine the role that ICG-based fluorescence has in identifying sentinel lymph nodes in MCC., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: No imaging algorithms for diagnostic imaging in patients suffering from Merkel cell carcinoma (MCC) have been established so far and thus staging work-up is challenging. Long presentation-to-treatment intervals determine further treatment course and, consequently, have an impact on clinical outcome in patients with MCC., Methods: In this retrospective study, diagnostic imaging of 37 MCC patients was analyzed. CT, ultrasound, and PET/PET-CT imaging for primary staging work-up with time frames from patients´ initial presentation and imaging until completion of tumor staging were analyzed., Results: Tumor staging could be completed earlier when (1) less examinations (35 vs. 42 days) were carried out or (2) computed tomography was used as the initial imaging modality (28 vs. 35 days). Furthermore, CT imaging, when used as the initial imaging study, was linked to less follow-up imaging (3 vs. 6)., Conclusion: Computed tomography as the first-staging imaging technique in MCC patients leads to less follow-up studies and fastest completion of tumor staging.

Aim: Real-world evidence of charted treatment responses to cancer drug therapy was compared with medical record derived radiographic measurements of target lesions per Response Evaluation Criteria in Solid Tumors (RECIST)., Materials & Methods: 15 physicians treating 59 metastatic Merkel cell cancer (mMCC) patients contributed patient-level data. A comparison of medical record reported best response with radiographic measurements per RECIST of pre- and post-treatment target lesions., Results: RECIST response rates were significantly lower compared with medical record reported with a concordance of 43.2% (95% CI: 28.0-58.4%)., Conclusion: Subjective assessment of tumor response collected via traditional chart abstraction may overestimate benefit and limit the potential role of real-world evidence in value-based care research. The use of target lesion measurements presents an attractive alternative that better aligns with trial results.

Introduction Merkel cell carcinoma (MCC) is a rare cutaneous tumour that is clinically aggressive with a high local, regional, and distant metastatic potential. Cases Three male patients presented to University Hospital Limerick (UHL) in 2015 with cutaneous lesions of the thorax, buttock and forearm. Once MCC was confirmed, management included surgical wide local excision (WLE) with regional lymph node dissection followed by adjuvant radiotherapy. One patient is in remission. The second has residual locoregional lymph node disease and is undergoing annual CT surveillance. The third had distant metastatic disease and is deceased from an unrelated condition. Discussion This case series highlights the presentation and management of MCC. We also discus relevant guidelines. The management of MCC is complex and there is a need to establish local or national databases to identify and monitor patients with MCC.

Introduction: TROG 09.03 prospectively studied the utility of Fluorine-18 Fluorodeoxyglucose (18-FDG) PET in the management of Merkel cell carcinoma of skin., Methods: Following consent and registration, a pre-treatment FDG-PET/CT was performed. Sites of avid disease were confirmed by cytology where practicable. Following surgery, patients with AJCCv7 Stages IIA-IIIB disease were treated with chemo-radiotherapy and reassessed with a post-treatment PET., Results: Fifty-eight subjects (45 males and 13 females, median age 68 years) were enrolled between 2011 and 2015, 43 patients of whom went on to receive chemo-radiotherapy. An occult primary was present in 22 (37.9%), T1 in 22 (37.9%) and T2 disease in 14 (24.1%). Nodal disease was present in 69% of cases. Fifty per cent of subjects had gross residual disease at the primary site and/or nodal site at the time of registration. 18-FDG PET/CT had a sensitivity of 94.74% (95% CI 82-99.3%) and a specificity of 88.24% (95% CI 63.56-98.54). The positive predictive value was 94.74% (83.01-98.51) and the negative predictive value was 88.24% (95% CI 65.81-96.69). The pre-treatment PET influenced a treatment decision in 27.6% of cases. Upstaging occurred in 15 (25.9%), with no down staging. Other diseases were identified in 4 (6.9%) patients. Univariate analysis failed to demonstrate that pre-treatment SUV levels or a negative post-treatment PET had any impact on overall survival. PET staged patients had 89% 3-year in-field loco-regional control and 76% 3-year overall survival., Conclusion: Staging 18-FDG-PET significantly influenced treatment decisions in approximately one-third of cases of MCC and should be considered in the routine pre-treatment work-up. Post-treatment PET was not found to be prognostic. Funding through the Medicare Benefits Schedule needs to be considered for high risk MCC., (© 2018 The Royal Australian and New Zealand College of Radiologists.)