Home   Chapter Home   Jobs   Conferences   Fellowships   Books



Advertisement

Skin - Nonmelanocytic tumors

Carcinoma (non-adnexal)

Merkel cell carcinoma


Reviewer: Christopher Hale, M.D. (see Reviewers page)
Revised: 20 March 2014, last major update June 2012
Copyright: (c) 2001-2012, PathologyOutlines.com, Inc.

General
=========================================================================

● Also called neuroendocrine carcinoma of skin
● Originally called trabecular carcinoma

Clinical features
=========================================================================

● Usually adults or elderly
● 60% women
● Face and extremities
● May be associated with squamous cell carcinoma (in situ or invasive), basal cell carcinoma, eccrine duct-like structures
● Aggressive
● Regional nodal metastases are common
● Distant metastases to liver, lung, bones; also testis or other unusual sites
● Rarely appears to arise initially in lymph node, probably due to regression of primary skin tumor
● May derive from Merkel cell in epidermis, derived from neural crest, important for tactile sensation in lower animals

Treatment
=========================================================================

● Wide local resection, regional lymph node resection
● Radiation therapy and chemotherapy as needed

Case reports
=========================================================================

● 55 year old woman presented with a skin nodule on the chest (Case of the Week #304)
● 65 year old man with FNA solid lesion left neck (See case report by Dr. Tim Bracey)
● 83 year old woman with left cheek lesion (Case Report Med 2010;2010:905414)

Clinical images
=========================================================================


   
Hip lesion

Gross description
=========================================================================

● Nodular or ulcerated red-violet lesion

Gross images
=========================================================================



Hip lesion

Micro description
=========================================================================

● Dermal or subcutaneous centered tumor with monotonous round tumor cells and diffuse infiltration of subcutis
● May have focal trabecular pattern
● Cells have scant eosinophilic cytoplasmic rim, round and vesicular nuclei with finely granular and dusty chromatin and multiple nucleoli
● Also apoptotic nuclei and frequent mitotic figures
● May have vascular stroma with plump endothelial cells
● Epidermis is usually spared
● Rarely has leiomyosarcoma or atypical fibroxanthoma-like areas

Micro images
=========================================================================


           

           

       

       
Various images

Case of the Week #304:



From left to right: Chromogranin, synaptophysin, cytokeratin, CK20, p63 #1 & #2

Cytology images
=========================================================================


Contributed by Dr. Tim Bracey, Plymouth Hospitals NHS Trust, UK: paranuclear blue dots


FNA by anonymous contributor (was CK20+ with perinuclear dot like staining, CD45-, TTF-; flow was CD56+, CD45-)

Positive stains
=========================================================================

● Low molecular weight keratin, CK20 (perinuclear dot like staining), EMA, neurofilament, neuron-specific enolase, CD56 (J Cutan Pathol 2005;32:541)
● Variable chromogranin, synaptophysin and CD117

Negative stains
=========================================================================

● TTF1, CD45/LCA

Electron microscopy
=========================================================================

● Dense core neurosecretory granules and tightly packed intermediate filaments
● Well developed desmosomes

Molecular
=========================================================================

● Abnormalities in #1, #11, #12
● 1p35-36 deletion

Differential diagnosis
=========================================================================

● Lymphoma
● Metastatic small cell carcinoma of lung
● Basal cell carcinoma

End of Skin - Nonmelanocytic tumors > Carcinoma (non-adnexal) > Merkel cell carcinoma


This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).