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
Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Pathophysiology | Clinical features | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosis | Additional referencesCite 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
- 36 year old man with lymph node melanosis and metastatic melanoma of unknown primary (Arch Pathol Lab Med 2009;133:1332)
- 83 year old man with melanosis coli involving pericolonic lymph nodes associated with the herbal laxative Swiss Kriss (Arch Pathol Lab Med 2004;128:565)
- Tumoral melanosis involving the sentinel lymph nodes (J Cutan Pathol 2007;34:284)
- Lymph node melanosis from a primary cutaneous lesion combining a nodular (tumoral) melanosis and a congenital dermal melanocytic nevus (Am J Dermatopathol 2012;34:653)
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:
Melanosis Coli in a pericolonic lymph node
H&E, CD68, HMB-45, S100
Pigment in colonic mucosa and colonic lymph nodes
Positive stains
Differential diagnosis
Additional references
