Primary merkel cell carcinoma clinically presenting as deep oedematous mass of the groin

Map of thrombogenesis in viral infections and viral-driven tumours

Viruses are pathogenic agents responsible for approximately 10% of all human cancers and significantly contribute to the global cancer burden. Until now, eight viruses have been associated with the development of a broad range of malignancies, including solid and haematological tumours. Besides triggering and promoting oncogenesis, viral infections often go hand-in-hand with haemostatic changes, representing a potential risk factor for venous thromboembolism (VTE). Conversely, VTE is a cardiovascular condition that is particularly common among oncological patients, with a detrimental impact on patient prognosis. Despite an association between viral infections and coagulopathies, it is unclear whether viral-driven tumours have a different incidence and prognosis pattern of thromboembolism compared to non-viral-induced tumours. Thus, this review aims to analyse the existing evidence concerning the association of viruses and viral tumours with the occurrence of VTE. Except for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection, which are associated with a high risk of VTE, little evidence exists concerning the thrombogenic potential associated with oncoviruses. As for tumours that can be induced by oncoviruses, four levels of VTE risk are observed, with hepatocellular carcinoma (HCC) and gastric carcinoma (GC) associated with the highest risk and nasopharyngeal carcinoma (NPC) associated with the lowest risk. Unfortunately, the incidence of cancer-related VTE according to tumour aetiology is unknown. Given the negative impact of VTE in oncological patients, research is required to better understand the mechanisms underlying blood hypercoagulability in viral-driven tumours to improve VTE management and prognosis assessment in patients diagnosed with these tumours.

Merkel cell carcinoma: A systematic review of the demographic and clinical characteristics of 847 cases in Japan

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine carcinoma of the skin associated with Merkel cell polyomavirus and immunosuppression. Although MCC incidence is rising worldwide, MCC has not been sufficiently investigated in Japan. This study aimed to determine MCC demographics in Japan, including incidence, age, sex, location, spontaneous regression, and pure/combined MCC. Using PubMed and Igaku Chuo Zasshi, 847 MCC cases between 1985 and 2015 were extracted, and the main epidemiological characteristics were described. The mean age of all patients was 77.5 years. Regarding the characterized lesions, 63.0% were located on the head and neck, 5.2% on the trunk, 12.6% on the upper limb, 15.1% on the lower limb, 3.5% on the buttocks, and 0.6% on the genitals. Histopathological information regarding the presence of other malignancies could be retrieved in 611 cases, and a coexisting malignancy, mainly squamous cell carcinoma and Bowen's disease, was present in 14.2%. Subcutaneous MCC was observed in 31 patients with a male : female ratio of 1.07 (16 men/15 women). Nodal lesions with unknown primary tumor location were described in 19 patients with a male : female ratio of 0.9 (nine men/10 women) and a mean age of 77.7 years. Of 640 evaluable cases, spontaneous regression developed in 9.1%. Among those 58 patients, the male : female ratio was 1:2.1 in 56 evaluable cases (18 men/38 women). Merkel cell polyomavirus was assessed in 180 patients, and the virus was detected in 31.1% and not detected in 68.9% of the patients. MCC is a rare disease in Japan, with incidence rates and male : female ratios differing from those in the USA and European countries. Besides, this study reveals the high frequency of subcutaneous MCC and MCC with divergent differentiation patterns and spontaneous regression in Japan compared to other countries.

Primary retroperitoneal Merkel cell carcinoma: Case report and literature review

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma that affects elderly patients and typically arises in sun-exposed skin. The disease is very rare and only few cases present with no apparent skin lesion. In the retroperitoneum there are only two cases reported in the literature.

CASE PRESENTATION

We report a case of a 54-year-old Mexican male with MCC, which presented as a large retroperitoneal mass. Pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen revealed a MCC. The patient underwent preoperative chemotherapy followed by a laparotomy and the mass was successfully excised.

DISCUSSION

There are two possible explanations for what occurred in our patient. The most plausible theory is the retroperitoneal mass could be a massively enlarged lymph node where precursor cells became neoplastic. This would be consistent with a presumptive diagnosis of primary nodal disease. Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin. The less probable theory is the non-described "regression" phenomena of a cutaneous MCC, but we are not found a primary skin lesion.

CONCLUSION

Preoperative chemotherapy and excision of the primary tumor is the surgical treatment of choice for retroperitoneal MCC. We propose that further studies are needed to elucidate the true efficacy of chemotherapy in conventional and unconventional patients with MCC.

Merkel cell carcinoma - recent advances in the biology, diagnostics and treatment

Merkel cell carcinoma (MCC) is an uncommon primary cutaneous carcinoma with neuroendocrine differentiation. Since recent discovery of MCCs strong association with Merkel cell polyomavirus (MCPyV), there has been a rapid increase in the understanding of the carcinomas genetics, molecular biology and pathogenesis. In our study, we reviewed recent advances and controversies concerning MCC histogenesis, epidemiology, diagnostic and prognostic markers. We analyzed the association of MCPyV with MCC and the possible new targets for therapy. We also examined English-based literature regarding MCC pathogenesis published between 2008 and 2013, which lead to a deeper understanding of the topic. Our study showed that the association of MCPyV strongly influences the course of MCC. Additionally, it has been shown that a immunological response to MCPyV may in the future give hope to identify new therapeutic strategies in treatment of this fatal malignancy. This article is part of a Directed Issue entitled: Rare Cancers.

Merkel cell carcinoma of the retroperitoneum with no identifiable primary site

Merkel cell carcinoma (MCC) is an extremely rare primary neuroendocrine neoplasm of the skin that shows aggressive behavior and a poor prognosis. We report a case of a 67-year-old male with a Merkel cell carcinoma which initially presented itself as a large retroperitoneal mass. Pathological and immunohistochemical analysis revealed tissue consistent with neuroendocrine carcinoma. Despite complete medical workup, no other primary MCC could be detected. While being an atypical presentation, the tumor mass showed an excellent response to the combination of chemotherapy followed by radiotherapy.

C-terminal deletions of Merkel cell polyomavirus large T-antigen, a highly specific surrogate marker for virally induced malignancy

In 67-100% of cutaneous Merkel cell carcinomas (MCC) the Merkel cell polyomavirus (MCPyV) integrates into the host genome. Mutations and deletions truncating the C-terminal helicase domain of the T-antigen (TAg) protein have been detected in these MCCs, but not in healthy skin specimens. C-terminal deletions of the TAg nucleic acid sequences are characteristic for about 38% of these cases. While the association of MCPyV with MCC has been proven, it is unknown whether MCPyV may play a similar role in other tumor entities. We describe in detail the development and validation of a novel Merkel cell polyomavirus TAg C-terminus deletion assay (MCPyV ΔC-TAg). The triplex real-time PCR quantifies the N- and C-terminal part of the MCPyV TAg gene and the cellular β-globin gene. By comparing the copy numbers of the N- and C-terminal part, deletions of the MCPyV TAg C-terminus are rapidly identified. MCPyV ΔC-TAg was used to assess the physical state of MCPyV TAg in a large series of 55 MCCs, 15 cutaneous lymphomas and 47 forehead smears of healthy individuals. Neither DNA positivity nor viral load was able to discriminate MCCs from the other different types of samples. However, deleted TAg C-terminus sequences were detected only in MCPyV positive MCCs (39%). Consequently, detection of deleted C-terminal TAg sequences appears to be a highly specific surrogate marker for virally induced malignancy and should be used to support novel assumed MCPyV-tumor associations. The study further supports the notion that MCPyV does not play a role in cutaneous lymphoma pathogenesis.