Primary Nodal Merkel Cell Carcinoma: Rare Presentation

Öz

Merkel cell carcinoma (MCC) is a very rare high-grade neuroendocrine carcinoma that is frequently located in the skin. Although most cases are associated with Merkel cell polyomavirus, there are also cases in which the virus cannot be detected. The purpose of presenting the case of MCC with primary nodal involvement is due to its rare presentation. A 59-year-old male patient presented to the hospital with painless mass in the neck. Imaging analyses revealed necrotic lymphadenopathies on the neck, measuring up to 4.5 cm in size. After an explorative surgery with preliminary diagnoses of lymphoma and squamous cell carcinoma , samples taken from the excised mass showed high-grade neuroendocrine carcinoma morphology. In addition to neuroendocrine markers, CK7 and CK20 positivity were observed in the immunohistochemical tests performed. The patient was diagnosed with primary nodal MCC due to the negativity of the markers performed to exclude other malignancies and the absence of a different focus on PET imaging analysis outside the lymph node. The differential diagnosis of MCC should be kept broad due to the histopathological morphology of small round cell malignant tumors. In high-grade neuroendocrine carcinomas, the possibility of MCC should be ruled out especially if CK20 positivity is present. Although is has been reported that primary nodal MCC cases have a better clinical course compared to nodal metastatic cases with a known primary, there are limited case series studies on this topic. A multisystem approach is recommended for proper clinical management.

Anahtar Kelimeler

• Nodal merkel cell carcinoma
• Merkel cell carcinoma of unknown origin
• High-grade neuroendocrine carcinoma

Primer Nodal Merkel Hücreli Karsinom: Nadir Prezentasyon

Öz

Merkel hücreli karsinom (MHK) sıklıkla deri yerleşimli oldukça nadir görülen yüksek dereceli nöroendokrin karsinomdur. Olguların çoğu Merkel cell polyomavirus ile ilişkilendirilmekle birlikte virusun saptanamadığı olgular da mevcuttur. Bu yazıda oldukça nadir bir prezentasyon olması nedeni ile primeri bulunamayan nodal MHK tanılı olgunun sunulması amaçlandı. 59 yaşında erkek hasta boynunda ağrısız ele gelen kitle varlığı nedeni ile hastaneye başvurdu. Görüntüleme analizlerinde boyunda 4,5 cm’e ulaşan lenfadenopati ile uyumlu nekrotik kitleler saptandı. Lenfoma ve skuamöz hücreli karsinom ön tanıları ile yapılan eksploratif cerrahi sonucunda gönderilen kitleden alınan örnekler yüksek dereceli nöroendokrin karsinom morfolojisinde idi. Yapılan immunhistokimyasal tetkiklerde nöroendokrin belirteçlerin yanısıra CK7 ve CK20 pozitifliği eşlik etmekte idi. Diğer maligniteleri dışlamak amacıyla yapılan belirteçlerin negatifliği ve PET görüntüleme analizinde lenf nodu dışında farklı bir odak saptanmaması nedeni ile olgu primer nodal MHK tanısı aldı. MHK’un histopatolojik olarak küçük yuvarlak hücreli malign tümör morfolojisi nedeni ile ayırıcı tanısı oldukça geniş tutulmalıdır. Yüksek dereceli nöroendokrin karsinomlarda CK20 pozitifliği durumunda MHK olasılığı mutlaka ekarte edilmelidir. Primer nodal MHK olgularının, primeri bilinen nodal metastatik olgulara göre daha iyi klinik seyir gösterdiği bildirilse de bu konuda küçük olgu serili çalışmalar mevcuttur. Doğru klinik yönetim için multisistemik bir yaklaşım önerilmektedir.

Anahtar Kelimeler

• Nodal merkel hücreli karsinom
• Primeri bulunamayan merkel hücreli karsinom
• yüksek dereceli nöroendokrin karsinom

Kaynakça

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