<abstract xmlns="http://www.w3.org/1999/xhtml">

<bold>Introduction</bold>: Merkel cell carcinoma is a very rare malignant neoplasm which presents high aggressivity, high recurrence rate and has meta-static potential. Our purpose is to present the histological and immunohistochemical particularities of Merkel Cell Carcinoma while reviewing potential differential diagnoses and challenges that we can encounter in daily practice.
<bold>Case presentation</bold>: We present the case of an 86-year-old female patient who presented with a nodular tumour located in the left forearm, raising suspicion of a soft tissue tumour. The histological appearance of this unique type of cancer is highlighted on the Haematoxylin-eosin stain as a solid tumour composed of nests and chords of monomorphic cells. The nuclei of these tumoral cells appear characteristically as enlarged with dispersed chromatin. The immunohistochemical reactions have been performed and it was observed that the tumoral cells exhibited positivity for synaptophysin, CD56, NSE, EMA, as well as a “dot-like” expression for CK20. These histopathological and immunohistochemical features were consistent with a diagnosis of MCC, stage pT3, based on the assessment of tumour size.
<bold>Conclusions</bold>: Sometimes, differentiating this tumour from other primary malignant neoplasms of the skin or even cutaneous metastases can be difficult. Immunohistochemistry remains the most important tool of diagnosis, especially for differentiating this neoplasm from metastatic neuroendocrine tumours that can affect the skin.
</abstract>

Introduction: Merkel cell carcinoma is a very rare malignant neoplasm which presents high aggressivity, high recurrence rate and has meta-static potential. Our purpose is to present the histological and immunohistochemical particularities of Merkel Cell Carcinoma while reviewing potential differential diagnoses and challenges that we can encounter in daily practice.
Case presentation: We present the case of an 86-year-old female patient who presented with a nodular tumour located in the left forearm, raising suspicion of a soft tissue tumour. The histological appearance of this unique type of cancer is highlighted on the Haematoxylin-eosin stain as a solid tumour composed of nests and chords of monomorphic cells. The nuclei of these tumoral cells appear characteristically as enlarged with dispersed chromatin. The immunohistochemical reactions have been performed and it was observed that the tumoral cells exhibited positivity for synaptophysin, CD56, NSE, EMA, as well as a “dot-like” expression for CK20. These histopathological and immunohistochemical features were consistent with a diagnosis of MCC, stage pT3, based on the assessment of tumour size.
Conclusions: Sometimes, differentiating this tumour from other primary malignant neoplasms of the skin or even cutaneous metastases can be difficult. Immunohistochemistry remains the most important tool of diagnosis, especially for differentiating this neoplasm from metastatic neuroendocrine tumours that can affect the skin.

Merkel cell carcinoma - particularities and morphological aspect of a unique and rare entity

George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures

Acta Marisiensis - Seria Medica

This work is licensed under the Creative Commons Attribution 4.0 International License.

Introduction: Merkel cell carcinoma is a very rare malignant neoplasm which presents high aggressivity, high recurrence rate and has meta-static potential. Our...

Merkel cell carcinoma - particularities and morphological aspect of a unique and rare entity

Published Online: Jul 03, 2024

Page range: 95 - 99

Received: Feb 21, 2024

Accepted: Apr 12, 2024

DOI: https://doi.org/10.2478/amma-2024-0008

Keywords
Merkel Cell Carcinoma, immunohistochemistry, rare neoplasm, malignant

© 2024 Andreea Cătălina Tinca et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Merkel cell carcinoma - particularities and morphological aspect of a unique and rare entity

Published Online: Jul 03, 2024

Page range: 95 - 99

Received: Feb 21, 2024

Accepted: Apr 12, 2024

DOI: https://doi.org/10.2478/amma-2024-0008

KeywordsMerkel Cell Carcinoma, immunohistochemistry, rare neoplasm, malignant

© 2024 Andreea Cătălina Tinca et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
Merkel Cell Carcinoma, immunohistochemistry, rare neoplasm, malignant