Lymph nodes & spleen, nonlymphoid
Lymph nodes-inclusions, pigment, ectopic cells or tissue
Melanosis


Topic Completed: 1 June 2014

Minor changes: 1 April 2020

Revised: 1 February 2019, last major update June 2014

Copyright: 2003-2020, PathologyOutlines.com, Inc.

PubMed Search: Melanosis [title] lymph node


Jayalakshmi Balakrishna, M.D.
Abdelsalam Sharabi, M.D.
Page views in 2019: 1,035
Page views in 2020 to date: 560
Cite this page: Balakrishna J. Melanosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lymphnodesmelanosiscoli.html. Accessed August 3rd, 2020.
Definition / general
  • A rare manifestation of a completely regressed melanoma
Terminology
  • Tumoral melanosis
  • Nodular melanosis
  • Nodal melanosis
Epidemiology
  • Very rare in lymph nodes
Sites
  • Sentinel lymph nodes of regressed melanoma
  • Mesenteric lymph nodes
Pathophysiology
  • Possibilities include:
    • A regressed focus of metastatic melanoma
    • Melanophages migrating to the lymph node from the primary lesion
Clinical features
  • Enlarged lymph nodes
  • Yellow brown spindle bodies in mesenteric nodes may be due to melanosis coli (Histopathology 1978;2:47)
  • The paucity of cases precludes adequate evaluation of long term implications and treatment outcomes
Case reports
Gross description
  • Enlarged lymph nodes with or without brown pigment deposition
Microscopic (histologic) description
  • Subcapsular and sinusoidal accumulation of pigmented cells with vesicular chromatin and inconspicuous nucleoli
  • The cells may be spindle shaped or epithelioid
Microscopic (histologic) images

Images hosted on other servers:
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Melanosis Coli in a pericolonic lymph node

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H&E, CD68, HMB-45, S100

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Pigment in colonic mucosa and colonic lymph nodes

Positive stains
Negative stains
Differential diagnosis
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