Merkel cell cancer classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Vamsikrishna Gunnam M.B.B.S [2]

Overview

Merkel cell carcinoma is classified into 3 subgroups: trabecular, intermediate, and small cell.

Histologically, MCC has been classified into three distinct subtypes:^[1]^[2]^[3]


Subtype	Pattern	Histology studies
Trabecular type	Classic pattern	Large-cells High density granules Organoid clusters of cells Trabeculae with ribbons Most commonly occurs in hair follicles
Intermediate type	Solid pattern	Most common subtype Compactly arranged cells Cytoplasm is less abundant in the cells Mitotic figures are positive Necrosis is positive Intermediate type may invade the epidermis More aggressive subtype when compared to the trabecular type
Small cell type	Diffuse pattern	Few high density granules Arises in the dermis Sheets of solid and clusters of cells Mimics other small cell tumours

↑ Koljonen V (February 2006). “Merkel cell carcinoma”. World J Surg Oncol. 4: 7. doi:10.1186/1477-7819-4-7. PMC 1382229. PMID 16466578.
↑ Suster S, Ronnen M, Lin E, Shewach-Millet M (June 1986). “Trabecular carcinoma of the skin simulating metastatic disease”. J Surg Oncol. 32 (2): 73–5. PMID 3724197.
↑ Johansson L, Tennvall J, Akerman M (August 1990). “Immunohistochemical examination of 25 cases of Merkel cell carcinoma: a comparison with small cell carcinoma of the lung and oesophagus, and a review of the literature”. APMIS. 98 (8): 741–52. PMID 1698390.