Metastatic Cancer: Melanoma

Gross Anatomy of Metastatic Melanoma

Lyz Boyd and Jennifer Kong

Learning Objectives

At the end of this section, you will be able to:

  • Name common sites of metastasis.
  • Upon visual inspection, identify key features of metastatic melanoma in organs.

 

Melanoma frequently metastasizes to the liver, lungs, and brain.  However, metastases can also occur in other organs.  The DHPLC collection is fortunate to have specimens (from various patients) of melanoma metastases in the liver, brain, lungs, kidneys and the heart.  Regardless of the metastatic site, the melanoma will look similar to that seen in the primary site (i.e. skin).  In essence, metastases will look like moles in these organs which normally would NOT have any melanocytes present.

Metastatic Melanoma in Liver (DHPLC Specimen: M0935) and Lung (DHPLC Specimen: A0901C) by Lyz Boyd, licensed under All rights reserved

 

Metastatic Melanoma in Brain (DHPLC Specimen: P0932 ) and Heart (DHPLC Specimen: B0901) by Lyz Boyd, licensed under All rights reserved

Melanoma can metastasize to other, less common, sites.  The following images are from different patients, all with metastatic melanoma.

a kidney and adrenal are visible with large, obvious black spots within and on top of the kidney. These black spots are melanoma metastases
Figure 4.17a  DHPLC Specimen: D0913Anterior View of Kidney and Adrenal Gland with Melanoma Metastases, licensed under All rights reserved 
Posterior view of kidney and adrenal with melanoma metastasis. The melanoma is about quarter the size of the kidney
Figure 4.17b DHPLC Specimen: D0913 – Posterior View of Kidney and Adrenal with Melanoma Metastasis, licensed under All rights reserved
Figure 4.18 DHPLC specimen: U0910Melanoma of Small Intestine, licensed under All rights reserved 

Recall that there are melanocytes in the uvea of the eye.  Although less common, melanoma can arise within the eye and metastasize to any of the pre-mentioned locations.

the interior of the eye is visible with the lens/pupil on the right and the optic nerve on the left. A very large brown melanoma "mole' is in the centre of the vitreous chamber, taking up approximately a quarter of the view.
Figure 4.19 DHPLC specimen Y0901Melanoma that Started in the Eye in the Melanocyte-rich Choroid Layer, licensed under All rights reserved 

Section Review

  • Common sites of metastasis are liver, lungs, and brain.
  • Metastasis can occur to other organs, provided that they have blood or lymphatic flow.  These abnormal melanocytes will grow in this new location, regardless of whether melanocytes were previously present. Thus melanoma will visually appear similar to those of the original site, but now in a distant organ:  dark, irregularly shaped and sized moles of varying colours.
  • Melanoma can also arise from tissues which also have melanocytes – the eye being an example of a less common origin of melanoma.

Review Questions

License

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Pathology Copyright © 2022 by Lyz Boyd and Jennifer Kong is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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